Patent Publication Number: US-9846440-B2

Title: Valve controller configured to estimate fuel comsumption

Description:
RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. application Ser. No. 13/326,691, entitled “Gas Valve with Fuel Rate Monitor,” filed on Dec. 15, 2011 and which is incorporated by reference herein in its entirety for all purposes. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates generally to systems and methods for determining energy consumption and more particularly, to controllers configured to determine energy consumption based at least in part on a control signal. 
     BACKGROUND 
     Commercial and industrial facilities consume large quantities of energy. One of the largest areas of energy consumption is fuel used for heating and processing. These commercial and industrial facilities often have multiple combustion appliances operating simultaneously. Examples of such appliances include boilers, direct/in-direct make-up air heaters, and power/jet burners. 
     Due to the large amount of energy consumed, it may be useful for facility management to estimate energy usage in various sectors of the facility and/or estimate the energy usage as it relates to specific processes. Such information may be necessary to document energy usage to meet emission requirements, anticipate the monthly energy bill, and to associate energy costs to specific departments and/or processes. Additionally, such information may also facilitate continual monitoring and assessment of facility energy consumption, and may also enable detection of unusual patterns of energy consumption indicative of non-optimum operation. 
     SUMMARY 
     The present disclosure relates generally to systems and methods for determining energy consumption and more particularly, to controllers configured to determine energy consumption based at least in part on a control signal. 
     In one illustrative embodiment, a fuel valve for controlling a firing rate of a combustion appliance, includes: a valve body having an inlet port and an outlet port and a fluid channel extending between the inlet port and the outlet port; a valve member situated within the fluid channel between the inlet port and the outlet port, the valve member configured to be moved between a first position and a second position to control a flow rate of fuel through the fluid channel and thus a firing-rate of a downstream combustion appliance; a valve actuator for moving the valve member between the first position and the second position; and a valve control module operatively coupled to the valve actuator for controlling the position of the valve member. In some instances, the valve control module includes: an input for receiving a firing rate control signal, wherein the firing rate control signal is indicative of a desired firing rate; a memory module storing a relationship between a desired firing rate and a resulting flow rate of fuel through the fuel valve; and a processing module configured to use the relationship stored in the memory module, along with the firing rate control signal, to determine and then store in the memory module one or more of a measure of cumulative fuel flow through the fuel valve over a predetermined period of time and a measure of instantaneous fuel flow through the fuel valve. 
     In another illustrative embodiment, a method of determining energy consumption includes: sending a firing rate control signal to a fuel valve, wherein the fuel valve has an outer housing; referencing one or more parameters that at least partially define a relationship between a firing rate and a resulting flow rate of fuel through the fuel valve, where the one or more parameters are stored in a memory module located within the outer housing of the fuel valve, to determine a measure of fuel flow through the fuel valve; and calculating a measure of fuel consumption of a combustion appliance based on the determined measure of fuel flow through the fuel valve. 
     In another illustrative embodiment, a building controller, includes: an output for providing a firing rate signal to each of two or more fuel valves, wherein the fuel valves are spaced from the building controller; an input terminal for receiving a measure of fuel consumption from each of the fuel valves, wherein the measure of fuel consumption is based on the firing rate signal provided to the corresponding fuel valve; and a display for displaying an indication of fuel consumption for each of the two or more fuel valves. The preceding summary is provided to facilitate an understanding of some of the innovative features unique to the present disclosure and is not intended to be a full description. A full appreciation of the disclosure can be gained by taking the entire specification, claims, drawings, and abstract as a whole. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure may be more completely understood in consideration of the following description of various illustrative embodiments in connection with the accompanying drawings, in which: 
         FIG. 1  is a schematic perspective view of an illustrative fluid valve assembly; 
         FIG. 2  is a schematic first side view of the illustrative fluid valve assembly of  FIG. 1 ; 
         FIG. 3  is a schematic second side view of the illustrative fluid valve assembly of  FIG. 1 , where the second side view is from a side opposite the first side view; 
         FIG. 4  is a schematic input side view of the illustrative fluid valve assembly of  FIG. 1 ; 
         FIG. 5  is a schematic output side view of the illustrative fluid valve assembly of  FIG. 1 ; 
         FIG. 6  is a schematic top view of the illustrative fluid valve assembly of  FIG. 1 ; 
         FIG. 7  is a cross-sectional view of the illustrative fluid valve assembly of  FIG. 1 , taken along line  7 - 7  of  FIG. 4 ; 
         FIG. 8  is a cross-sectional view of the illustrative fluid valve assembly of  FIG. 1 , taken along line  8 - 8  of  FIG. 2 ; 
         FIG. 9  is a schematic diagram showing an illustrative fluid valve assembly in communication with a building control system and an appliance control system, where the fluid valve assembly includes a differential pressure sensor connect to a valve controller; 
         FIG. 10  is a schematic diagram showing an illustrative fluid valve assembly in communication with a building control system and an appliance control system, where the fluid valve assembly includes multiple pressure sensors connected to a valve controller; 
         FIG. 11  is a schematic diagram showing an illustrative schematic of a low gas pressure/high gas pressure limit control; 
         FIG. 12  is a schematic diagram showing an illustrative schematic valve control and combustion appliance control, where the controls are connected via a communication link; 
         FIG. 13  is a schematic diagram showing an illustrative valve control and proof of closure system in conjunction with a combustion appliance; 
         FIGS. 14-17  are various illustrative schematic depictions of different methods for sensing a position and/or state of a valve within an illustrative valve assembly; and 
         FIGS. 18-21  show several graphs illustrating the effect of a correction factor on the relationship between firing rate and flow rate. 
     
    
    
     While the disclosure is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit aspects of the disclosure to the particular illustrative embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure. 
     DESCRIPTION 
     The following description should be read with reference to the drawings wherein like reference numerals indicate like elements throughout the several views. The detailed description and drawings show several illustrative embodiments which are meant to be illustrative of the claimed disclosure. 
     Gas valves may be added to fluid path systems supplying fuel and/or fluid to appliances (e.g., burners, etc.) or may be used individually or in different systems. In some instances, gas safety shutoff valves may be utilized as automatic redundant valves. Redundancy is achieved, and often times required by regulatory agencies, by placing at least two safety shutoff valves in series. The aforementioned redundant valves may be separate valves fitted together in the field and/or valves located together in a single valve body, these redundant valves are commonly referred to as double-block valves. In accordance with this disclosure, these and other gas valves may be fitted to include sensors and/or switches and/or other mechanical or electronic devices to assist in monitoring and/or analyzing the operation of the gas valve and/or connected appliance. The sensors and/or switches may be of the electromechanical type or the electronic type, or of other types of sensors and/or switches, as desired. 
     In some cases, a gas valve assembly may be configured to monitor and/or control various operations including, but not limited to, monitoring fluid flow and/or fluid consumption, electronic cycle counting, overpressure diagnostics, high gas pressure and low gas pressure detection, valve proving system tests, valve leakage tests, proof of valve closure tests, diagnostic communications, and/or any other suitable operation as desired. In addition, a gas valve assembly may be configured to calculate the instantaneous and/or cumulative fluid consumption of a connected combustion appliance. 
     Valve Assembly 
       FIG. 1  is a schematic perspective view of an illustrative fluid (e.g., gas, liquid, etc.) valve assembly  10  for controlling fluid flow to a combustion appliance or other similar or different device. In the illustrative embodiment, the gas valve assembly  10  may include a valve body  12 , which may generally be a six sided shape or may take on any other shape as desired, and may be formed as a single body or may be multiple pieces connected together. As shown, valve body  12  may be a six-sided shape having a first end  12   a , a second end  12   b , a top  12   c , a bottom  12   d , a back  12   e  and a front  12   f , as depicted in the various views of  FIGS. 1-6 . The terms top, bottom, back, front, left, and right are relative terms used merely to aid in discussing the drawings, and are not meant to be limiting in any manner. 
     The illustrative valve body  12  includes an inlet port  14 , an outlet port  16  and a fluid path or fluid channel  18  extending between inlet port  14  and outlet port  16 . Further, valve body  12  may include one or more gas valve ports  20  (e.g., a first valve port  20   a  and a second valve port  20   b , shown in  FIGS. 7 and 8 ) positioned or situated in fluid channel  18 , one or more fuel or gas valve member(s) sometimes referred to as valve sealing member(s)  22  movable within gas valve ports  20  (e.g., a first valve sealing member  22   a  within first valve port  20   a  and a second valve sealing member  22   b  within second valve port  20   b , as shown in  FIG. 7 ), one or more pressure sensor assemblies  24  (as shown in  FIG. 8 , for example), one or more position sensors  48 , and/or one or more valve controllers  26  (as shown in  FIG. 8 , for example) affixed relative to or coupled to valve body  12  and/or in electrical communication (e.g., through a wired or wireless connection) with pressure sensor assemblies  24  and position sensor(s)  48 . 
     Valve assembly  10  may further include one or more actuators for operating moving parts therein. For example, valve assembly  10  may have actuators including, but not limited to, one or more stepper motors  94  (shown as extending downward from bottom  12   d  of valve body  12  in  FIG. 1 ), one or more solenoids  96  (shown as extending upward from top  12   c  of valve body  12  in  FIG. 1 ), and one or more servo valves  98  (a servo valve  98  is shown as extending upward from top  12   c  of valve body  12  in  FIG. 1-3 , where a second servo valve has been omitted), where servo valve  98  may be a 3-way auto-servo valve or may be any other type of servo valve. In one illustrative embodiment, the one or more solenoids  96  control whether the one or more gas valve ports  20  are open or closed. The one or more stepper motors  94  determine the opening size of the gas valve ports  20  when the corresponding gas valve sealing member  22  is opened by the corresponding solenoid  96 . Of course, the one or more stepper motors  94  would not be provided when, for example, the valve assembly  10  is not a “modulating” valve that allows more than one selectable flow rate to flow through the valve when the valve is open. 
     As shown, valve body  12  may include one or more sensor and electronics compartments  56 , which in the illustrative embodiment, extend from back side  12   e  as depicted in  FIGS. 1, 2 and 4-6 . Sensor and electronics compartments  56  may be coupled to or may be formed integrally with valve body  12 , and may enclose and/or contain at least a portion of valve controllers  26 , pressure sensors assemblies  24  and/or electronics required for operation of valve assembly  10  as described herein. Although compartments  56  may be illustratively depicted as separate structures, compartments  56  may be a single structure part of, extending from, and/or coupled to valve body  12 . 
     In the illustrative embodiment, the one or more fluid valve ports  20  may include first gas valve port  20   a  and second gas valve port  20   b  situated along and/or in communication with fluid channel  18 . This is a double-block valve design. Within each gas valve port  20 , a gas valve sealing member  22  may be situated in fluid channel  18  and may be positioned (e.g., concentrically or otherwise) about an axis, rotatable about the axis, longitudinally and axially translatable, rotationally translatable, and/or otherwise selectively movable between a first position (e.g., an open or closed position) and a second position (e.g., a closed or open position) within the corresponding valve port  20 . Movement of the valve sealing member  22  may open and close valve port  20 . 
     It is contemplated that valve sealing member  22  may include one or more of a valve disk  91 , a valve stem  92  and/or valve seal  93  for sealing against a valve seat  32  situated in fluid channel  18 , as best seen in  FIGS. 14-17 , and/or other similar or dissimilar components facilitating a seal. Alternatively, or in addition, valve sealing member  22  may include structural features and/or components of a gate valve, a disk-on-seat valve, a ball valve, a butterfly valve and/or any other type of valve configured to operate from a closed position to an open position and back to a closed position. An open position of a valve sealing member  22  may be any position that allows fluid to flow through the respective gas valve port  20  in which the valve sealing member  22  is situated, and a closed position may be when valve sealing member  22  forms at least a partial seal at the respective valve port  20 , such as shown in  FIG. 7 . Valve sealing member  22  may be operated through any technique. For example, valve sealing member  22  may be operated through utilizing a spring  31 , an actuator  30  to effect movement against the spring  31 , and in some cases a position sensor  48  to sense a position of the valve sealing member  22 . 
     Valve actuator(s)  30  may be any type of actuator configured to operate valve sealing member  22  by actuating valve sealing member  22  from the closed position to an open position and then back to the closed position during each of a plurality of operation cycles during a lifetime of the gas valve assembly  10  or of actuator  30 . In some cases, valve actuator  30  may be a solenoid actuator (e.g., a first valve actuator  30   a  and a second valve actuator  30   b , as seen in  FIG. 7 ), a hydraulic actuator, magnetic actuators, electric motors, pneumatic actuators, and/or other similar or different types of actuators, as desired. In the example shown, valve actuators  30   a ,  30   b  may be configured to selectively move valves or valve sealing members  22   a ,  22   b  of valve ports  20   a ,  20   b  between a closed position, which closes the fluid channel  18  between inlet port  14  and the outlet port  16  of valve body  12 , and an open position. The gas valve assembly of  FIGS. 1-8  is an example of a gas safety shutoff valve, or double-block valve. In some cases, however, it is contemplated that the gas valve assembly  10  may have a single valve sealing member  22   a , or three or more valve sealing members  22  in series or parallel, as desired. 
     In some cases, valve assembly  10  may include a characterized port defined between inlet port  14  and outlet port  16 . A characterized port may be any port (e.g., a fluid valve port  20  or other port or restriction through which fluid channel  18  may travel) at or across which an analysis may be performed on a fluid flowing therethrough. For example, if a flow resistance of a valve port  20  is known over a range of travel of the valve sealing member  22 , the one of the one or more gas valve ports  20  may be considered the characterized port. As such, and in some cases, the characterized port may be a port  20  having valve sealing member  22  configured to be in an open position and in a closed position. Alternatively, or in addition, a characterized port may not correspond to a gas valve port  20  having valve sealing member  22 . Rather, the characterized port may be any constriction or feature across which a pressure drop may be measured and/or a flow rate may be determined. 
     In some cases, the characterized port may be characterized at various flow rates to identify a relationship between a pressure drop across the characterized port and the flow rate through the fluid channel  18 . Additionally or alternatively, the characterized port may be characterized at various firing rates to identify a relationship between a firing rate and a pressure drop across the characterized port. In both examples cases, the pressure drop may be measured directly with one or more pressure sensors  42 ,  43 ,  44 , and/or  38 . In other cases, the pressure drop may be inferred from, for example, the current position of the valve member(s). In still other cases, the characterized port also may be characterized at different firing rates to identify a relationship between firing rate and flow rate through the fluid channel  18 . In some cases, the relationship(s) may be stored in a memory  37 , such as a RAM, ROM, EEPROM, other volatile or non-volatile memory, or any other suitable memory of the gas valve assembly  10 , but this is not required. For example, the memory  37  may store one or more data tables or look-up tables recording the different relationships (e.g. pressure drop vs. flow rate; pressure drop vs. firing rate; and firing rate vs. flow rate). The memory  37  may also store a Wobbe Index associated with the fuel flowing through the fluid channel. The Wobbe Index may be used to determine cumulative and/or instantaneous fuel consumption in units of energy per unit time (e.g. BTU/hour) based on fluid flow rates or the volume of flow through the fluid channel  18 . 
     In some cases, gas valve assembly  10  may include a flow module  28  for sensing one or more parameters of a fluid flowing through fluid channel  18 , and in some cases, determining a measure related to a gas flow rate of the fluid through the fluid channel  18 . In some instances, flow module  28  may include a pressure block or pressure sensor assembly  24 , a temperature sensor  34 , a valve member position sensor  48  and/or a valve controller  26 , among other assemblies, sensors and systems for sensing, monitoring and/or analyzing parameters of a fluid flowing through fluid channel  18 , such as can be seen in  FIGS. 9 and 10 . 
     It is contemplated that flow module  28  may utilize any type of sensor to facilitate determining a measure related to a flow rate of a fluid through fluid channel  18 , such a pressure sensor, a flow sensor, a valve position sensor, and/or any other type of sensor, as desired. In one example, the flow module  28 , which in some cases may be part of a valve controller  26 , may be configured to monitor a differential pressure across a characterized port, and in some cases, a position of one or more valve sealing members  22  of the gas valve assembly  10 . The information from monitoring may be utilized by the flow module  28  to determine and monitor the flow rate of fluid (liquid or gas) passing through the fluid channel  18 . In some cases, the flow module  28  may determine a measure that is related to a gas flow rate through the fluid channel  18  based, at least in part, on the measure that is related to the pressure drop across the characterized port along with the pre-stored relationship in the memory  37 . Additionally, the flow module  28  may further determine a relationship between a desired firing rate and the measure related to a gas flow rate based, at least in part, on a previously established relationship stored in the memory  37 . In some cases, the current position of one or more valve sealing members  22  of the gas valve assembly  10  may also be taken into account (e.g. is the valve 30% open, 50% open or 75% open). 
     The different relationships described herein may be generated during installation and/or calibration of the valve assembly  10 , and may be stored as data tables or curves in the memory  37 . Using the previously established relationship(s) between flow rate and firing rate and/or flow rate and pressure drop across the characterized port stored in the memory  37  and a firing rate control signal received at the valve assembly  10  from another device (e.g. building controller, system level controller or combustion appliance controller) within the system, the flow module  28  may be further configured to determine a measure of fuel flow through the valve assembly  10 . In some instances, the flow module  28  may be configured to determine a measure of cumulative fuel flow through the fluid channel  18  over a predetermined period of time. Additionally, or alternatively, the flow module  28  may be configured to determine a measure of instantaneous fuel flow through the fluid channel  18  in real time. Cumulative fuel consumption and/or instantaneous fuel consumption may be calculated from the fuel flow based, at least in part, on the Wobbe Index associated with the fluid flowing through the fluid channel  18 , which also may be stored in the memory  37  of the valve assembly  10 . 
     In some instances, the flow module  28  may be configured to output the flow rate of fluid passing through the fluid channel  18  to a display or a remote device. In some cases, the flow module  28  may maintain a cumulative gas flow amount passing through the fluid channel  18  (e.g. over a predetermined time period), if desired. The measure related to a gas flow may include, but is not limited to, a measure of fuel consumption by a device or appliance that is connected to an output port  16  of the gas valve assembly  10 . As such, in some cases, the flow module  28  may output a measure of an instantaneous fuel consumption and/or cumulative fuel consumption by a device or appliance that is connected to an output port  16  of the valve assembly  10  over a predetermined period of time. The measure of fuel consumption may be based, at least in part, on a stored relationship between a desired firing rate and the flow rate of fuel through the valve. Fluid consumption, which is based on flow rate, may be converted to units of energy based, at least in part, on the Wobbe Index associated with the fluid flowing through the fluid channel  18 . The Wobbe Index associated with the fluid flowing through the fluid channel  18  may be stored in the memory  37  of the valve assembly  10 . This is just one example. 
     It is contemplated that electronic valve controller or valve control block  26  (see,  FIG. 8-10 ) may be physically secured or coupled to, or secured or coupled relative to, valve body  12 . Valve controller  26  may be configured to control and/or monitor a position or state (e.g., an open position and a closed position) of valve sealing members  22  of valve ports  20  and/or to perform other functions and analyses, as desired. In some cases, valve control block  26  may be configured to close or open gas valve member(s) or valve sealing member(s)  22  on its own volition, in response to control signals from other systems or appliances (e.g., a system level controller, central building controller, or combustion appliance controller), and/or in response to received measures related to sensed pressures upstream, intermediate, and/or downstream of the characterized valve port(s), measures related to a sensed differential pressure across the characterized valve port(s), measures related to temperature sensed upstream, intermediate, and/or downstream of the characterized valve port(s), and/or in response to other measures, as desired. In one example, the valve control block  26  may be configured to close or open gas valve member(s) or valve sealing member(s)  22  in response to receiving a firing rate control signal from a system or building level controller or an appliance controller (e.g. burner controller) to control a rate of flow of a fluid through the valve assembly  18  and to a connected appliance. 
     The memory  37 , which in some cases may be part of valve controller  26 , may be configured to record data related to sensed pressures, sensed differential pressures, sensed temperatures, and/or other measures. The valve controller  26  may access this data, and in some cases, communicate (e.g., through a wired or wireless communication link  100 ) the data and/or analyses of the data to other systems (e.g., a system level or central building control) as seen in  FIGS. 9 and 10 . The memory  37  and/or other memory may be programmed and/or developed to contain software to affect one or more of the configurations described herein. 
     In some instances, valve controller  26  may be considered a portion of flow module  28 , flow module  28  may be considered part of valve controller  26 , or the flow module  28  and valve controller  26  may be considered separate systems or devices. In some instances, valve controller  26  may be coupled relative to valve body  12  and one or more gas valve ports  20 , where valve controller  26  may be configured to control a position (e.g., open or closed positions, including various open positions) of valve sealing member  22  within valve port  20 . In some cases, the valve controller  26  may be coupled to pressure sensor assembly  24 , temperature sensor  34 , position sensor  48 , and/or other sensors and assemblies, as desired. 
     In the illustrative embodiment of  FIG. 8 , valve controller  26  may be configured to monitor a differential pressure across a characterized port. In some instances, valve controller  26  may monitor a differential pressure across fluid valve port  20  and/or monitor a measure related to a pressure upstream of a fluid valve port  20  (e.g., first valve port  20   a ) and/or a measure related to a pressure downstream of a fluid valve port  20  (e.g., second valve port  20   b ). The valve controller  26  may also be configured to monitor an axial position of the valve sealing member  22  in valve port  20 . As a result, valve controller  26  may determine a flow rate of fluid passing through the characterized port, where valve controller  26  may determine the flow rate (and in some cases, fluid consumption) based, at least in part, on the monitored differential pressure and/or monitored upstream and downstream pressures in conjunction with a pre-characterized relationship between the pressure drop across the characterized port and the flow rate. Valve controller  26  may also determine fluid consumption based on a known relationship between a desired firing rate and the flow rate through the valve. Flow rate may be converted to units of energy based, at least in part, on the Wobbe Index associated with the fluid flowing through the fluid channel  18 , which may be stored in the memory  37  of the valve assembly  10 . In some cases, the monitored axial positioning of valve sealing member  22  may also be taken into account, particularly when the valve sealing member  22  may assume one or more intermediate open positions between the fully closed and fully opened positions. When so provided, the pre-characterized relationship between the pressure drop across the characterized port and the flow rate may depend on the current axial positioning of valve sealing member  22 . 
     In some instances, valve controller  26  may include a determining block, which may include a microcontroller  36  or the like, which may include or be in communication with a memory, such as a non-volatile memory  37 . Alternatively, or in addition, determining block (e.g. microcontroller  36 ) may be coupled to or may be configured within valve control block or valve controller  26 . Determining block may be configured to store and/or monitor one or more parameters, which may be used when determining a measure that is related to a fluid flow rate through fluid channel  18 . Determining block (e.g. microcontroller  36 ) may be configured to use the stored and/or monitored parameters (e.g. the relationship between a pressure drop across a characterized port and the flow rate through the fluid channel  18  or the relationship between a desired firing rate and the flow rate through the channel  18 ) stored in the memory  37  to help determine a measure that is related to a fluid flow rate through fluid path or fluid channel  18 . 
     Illustratively, determining block (e.g. microcontroller  36 ) may be configured to determine and/or monitor a measure (e.g., a flow rate of fluid passing through the characterized port or other similar or different measure, as desired) based, at least in part, on stored and/or monitored measures including, but not limited to, measures related to pressure drop across a characterized valve port or other pressure related measures upstream and downstream of the characterized valve port, an ambient pressure at the valve assembly  10 , a temperature of the fluid flowing through fluid channel  18 , and/or a measure related to a current position of valve sealing member  22  at gas valve port  20  or the size of an opening at the characterized port. In some cases, the relationships between flow rate and differential pressure and/or flow rate and a desired firing rate stored in the memory  37  may be dependent, at least in part, on the sensed temperature of the fuel flowing through the fluid channel  18 , a sensed ambient pressure at the valve assembly  18  and/or other factors. In one example, a determining block (e.g. microcontroller  36 ) may include non-volatile memory  37  that is configured to store opening curves of valve assembly  10 , where the opening curves may characterize, at least in part, a flow rate as a function of a sensed axial position of valve sealing member  22 , and a sensed differential pressure across a characterized valve port  20  or an otherwise determined pressure at or adjacent a characterized valve port  20  (e.g., knowing a set-point of an upstream pneumatic pressure reducing valve (PRV), as the set-point pressure of the PRV may be substantially equal to the pressure at an inlet of the characterized valve port). The opening curves stored in the memory  37  of the valve assembly  10  may facilitate determining an instantaneous and/or cumulative fluid (e.g., fuel) flow in fluid channel  18  and/or consumption by an appliance in fluid communication with valve assembly  10 . In another example, the determining block (e.g. microcontroller  36 ) may include a memory  37  storing calibration curves of valve assembly  10 . The calibration curves may be generated by a technician at the time of commissioning of the valve assembly  10 . The calibration curves may characterize a relationship between flow rate and a sensed differential pressure across a characterized valve port  20  and/or flow rate as a function of firing rate. Also, in some embodiments, an installer may measure differential pressure across the burner orifice. Using burner manufacturer&#39;s data (e.g. a pressure drop at a certain flow through the burner), the measured differential pressure at a given firing rate may be converted to a calculated flow at a given firing rate and stored in the memory  37  of the valve assembly  10 . 
     In some cases, a sensed temperature of the fuel flowing through the fluid channel  18  and/or the sensed ambient pressure at the valve assembly  10  may be used to adjust the opening curves and/or calibration curves accordingly. Other corrective factors such as, for example, a measured excess air ratio, flue gas oxygen, flue gas temperature, altitude, ambient pressure, gas temperature, gas pressure, and/or the like also may be used to adjust the opening curves (e.g. firing rate vs. flow rate curve) stored in the memory  37 . Using different correction factors, not limited to the sensed temperature of the fuel and/or the ambient pressure, to adjust the curves may facilitate a more accurate determination of an instantaneous and/or cumulative fluid (e.g., fuel) flow in fluid channel  18  and/or consumption by an appliance in fluid communication with valve assembly  10 . This may be useful when determining an amount of energy (i.e. fuel) consumed by an appliance and consequently, an energy cost associated with fuel consumption. 
     It is contemplated that determining block (e.g. microcontroller  36 ) may continuously or non-continuously control, store, and/or monitor a position (e.g., an axial or rotary position or open/closed state or other position) of valve sealing member  22  within valve port  20 , monitor a differential pressure across the characterized port, and/or monitor a temperature upstream and/or downstream of the characterized port. In addition, microcontroller  36  may continuously or non-continuously determine the flow rate of the fluid passing through the characterized port, where microcontroller  36  may be configured to record in its memory or in another location, a desired firing rate, an instantaneous flow rate of fluid flowing through the characterized port, a cumulative flow volume, and/or a determined instantaneous or cumulative (e.g., total) fluid consumption based on the positions of valve sealing member(s)  22 , the desired firing rate, and the determined flow rates at an instant of time or over a specified or desired time period. In addition, determining block (e.g. microcontroller  36 ) may be configured to report out the instantaneous flow rate, cumulative flow volume and/or total or cumulative fluid consumption over a given time period. Fluid consumption may be converted to units of energy based, at least in part, on the Wobbe Index associated with the fluid flowing through the fluid channel  18 . The Wobbe Index associated with the fluid flowing through the fluid channel  18  may be stored in the memory  37  of the valve assembly  10 . 
     Determining block (e.g. microcontroller  36 ) may report the instantaneous flow rate, cumulative flow rate, and/or total or cumulative consumption of the fluid flowing through the characterized port to system display  52  of an overall system controller  50  (e.g., a building/industrial automation system (BAS/IAS) controller), an appliance display  62  of an appliance controller  60  where the appliance may be configured to receive the flowing fluid, a display adjacent gas valve assembly  10 , or any other display, device, controller and/or memory, as desired. 
     In some cases, the overall system controller  50  may receive a measure of fuel consumption from each of two or more fuel valves  10  in a system. As discussed herein, in one example, the measure of fuel consumption may be based on a firing rate signal provided to the corresponding fuel valve from the system controller  50  or another controller (e.g. appliance controller  60 ). The system display  52  may display an instantaneous or cumulative fuel consumption for each individual valve from which it receives a signal indicative of a measure of fuel consumption. In some cases, if the indication of fuel consumption falls above or below a predetermined specification or falls outside the boundaries of a predetermined range for a selected valve, the display (system display  52  or appliance display  62 ) may visually emphasize or otherwise indicate that the fuel consumption for a given valve is out of the specified limits. A visual indication that the fuel consumption for a selected valve is outside of specified limits may also be displayed on the display of the individual valve. In some cases, the valve controller  36  or the system controller  50  may be configured to transmit a message or other alarm over a communications network to a remote device indicating that the fuel consumption has fallen outside specified limits. 
     In some instances, valve controller  26  may include or be in communication with a valve actuator  30 , which in conjunction with stepper motor  94  or other device is configured to position valve sealing member  22  in valve port  20 . Valve actuator  30  and/or stepper motor  94  may be in communication with microcontroller  36  of valve controller  26 , and microcontroller  36  may be configured to control, monitor, and/or record the position (e.g., axial position, radial position, etc.) of valve sealing member  22  within valve port  20  through valve actuator  30  (e.g., valve actuator  30  may be configured to effect the locking (e.g., valve actuator  30  OFF) or the unlocking (e.g., valve actuator  30  ON) of the valve sealing member  22  in a particular position) and stepper motor  94  (e.g., stepper motor  94  may be configured to adjust the position of valve sealing member  22  when it is not locked in a particular position), or through only stepper motor  94 . Alternatively, or in addition, microcontroller  36  may be configured to monitor and record the position of valve sealing member  22  within valve port  20  through a connection with a position sensor  48  or through other means. 
     Microcontroller  36  may continuously or non-continuously monitor and record the position (e.g., axial position, radial position, etc.) of valve sealing member  22  within valve port  20  through valve actuator  30  and stepper motor  94 , and microcontroller  36  may indicate the sensed and/or monitored position of valve sealing member  22  within valve port  20  as a prescribed position of valve sealing member  22 . The prescribed position of valve sealing member  22  may be the position at which valve sealing member  22  was and/or is to be located, whereas a position of valve sealing member  22  sensed by position sensor system  48  may be considered an actual position of valve sealing member  22  within valve port  20 . 
     In some instances, valve controller  26  may be configured to perform electronic operational cycle counting or may include an electronic counter configured to count each operational valve cycle of valve sealing members  22  during, for example, the lifetime of gas valve assembly  10  or during some other time period. In some cases, microprocessor  36  of valve controller  26  may be configured to monitor a total number of operational cycles (e.g., the number of times fuel valve sealing members  22  are operated from a closed position to an open position and back to a closed position) of valve ports  20  and measures related thereto. In some cases, microprocessor  36  may store such data in a non-volatile memory, such as memory  37 , sometimes in a tamper proof manner, for record keeping and/or other purposes. Microprocessor  36  may monitor the number of cycles of valve sealing members  22  in one or more of several different manners. For example, microprocessor  36  may monitor the number of cycles of valve sealing members  22  by monitoring the number of times first main valve switch  72  and/or second main valve switch  74  are powered or, where one or more control signals may be provided to fuel valve actuator(s)  30  controlling when fuel valve actuator(s)  30  selectively moves (e.g., opens or closes) valve sealing member(s)  22 , microprocessor  36  may monitor the one or more control signals. 
     Valve controller  26 , in some cases, may monitor main valve switches  72 ,  74  by receiving signals directly from a device located remotely from valve assembly  10  on which main valve switches  72 ,  74  may be located (e.g. see  FIGS. 11-12 ). Switches ((main valve switches  72 ,  74  and safety switch  70  (discussed below)) may be any mechanism capable of performing a switching function including, but not limited to, relays, transistors and/or other solid state switches and circuit devices and/or other switches. Valve controller  26  may include an electrical port, sometimes separate from a communications interface  110  (discussed below), for receiving one or more control signals from the device located remotely from valve assembly  10 . The one or more control signals received via the electrical port may include, but are not limited to: a first valve port  20   a  control signal that, at least in part, may control the position of first valve sealing member  22   a  via first valve actuator  30   a , and a second valve port  20   b  control signal that, at least in part, may control the position second valve sealing member  22   b  via second valve actuator  30   b.    
     As an alternative to monitoring control signals, or in addition, microprocessor  36  may monitor the number of cycles of valve sealing members  22  by monitoring data from a position sensor  48 . For example, microprocessor  36  of valve controller  26  may monitor position sensor  48  and record the number of times valve sealing members  22  are in an open position after being in a closed position and/or the number of times valve sealing members  22  are in a closed position after being in an open position and/or the number of times valve sealing members are operated from a close position to an open position and back to a closed position. These are just some examples. Further, if valve controller  26  is operating valve sealing members  22 , valve controller  26  may monitor the number of operational cycles by counting its own control signals sent to valve actuators  30  and/or stepper motors  94 . 
     The non-volatile memory  37 , which may maintain and/or store the number of operational valve cycles, may be positioned directly on, or packaged with, valve body  12  (e.g., on or within memory of microcontroller  36 ) and/or may be accessible by valve controller  26 . Such storage, placement and/or packaging of valve cycle data may allow for replacement of components in the overall system (e.g., an appliance control  60 , etc.) without losing the valve cycle data. In an illustrative instance, valve cycle data may be securely stored, such that it may not be tampered with. For example, the valve cycle data may be stored the non-volatile memory  37  of valve controller  26  and the valve cycle data may be password protected. 
     Microcontroller  36  of valve assembly  10  may be configured to compare a count of a total number of operational cycles of valve sealing members  22  to a threshold number of operational cycles. In an instance where the counted number of operational cycles of the valve sealing member(s)  22   t  approaches, meets, or exceeds the threshold number of cycles, microcontroller  36  may initiate a warning and/or request a switch  69  in a limit string  67  to open and thus, remove or cut power to valve switches  72 ,  74  and fuel valve actuator(s)  30 . Alternatively, or in addition, microcontroller  36  may send a signal to initiate an alarm and/or put the system in a safety lockout, or microcontroller  36  may be configured to take other action as desired. Illustratively, microcontroller  36  may be configured to prevent fuel valve actuator(s)  30  from allowing valve sealing member(s)  22  to open after the total number of operational cycles meets and/or exceeds the threshold number of operational cycles. In some instances, the threshold number of cycles may be related to the number of cycles for which valve assembly  10  is rated (e.g., a maximum number of cycles before failures might be expected, etc.) or related to any other benchmark value. In addition, microcontroller  36  may be configured to perform other diagnostics based on analyzing captured operational cycle data, where the other diagnostics may include number of cycles, time duration of cycles, and similar or different diagnostics, as desired. 
     Valve controller  26  may include an I/O or communications interface  110  with a communication protocol for transmitting data to and/or otherwise communicating with one or more remote device(s) that may be located remotely from valve assembly  10  (e.g., a combustion appliance including controller  60  located remotely from valve assembly  10 ). Communications interface  110  may be a wired or wireless communication interface, where the wired or wireless communication interface  110  may be configured to be compatible with a predetermined communication bus protocol or other communication protocol. A wired link may be low voltage (e.g. 24V, 5V, 3V, etc.), which may reduce certain issues related to line-voltage wiring schemes. Illustratively, communications interface  110 , using the predetermined communication bus protocol or other communication protocol, may be configured to output and/or communicate one or more valve conditions, one or more measures related to valve conditions, one or more conditions related to a fluid flow through fluid channel  18 , and/or one or more diagnostic parameters, conditions or events, to a device located adjacent or remote from valve assembly  10 . 
     As discussed, valve controller  26  may be configured to determine one or more valve conditions based on one or more diagnostic parameters related to fluid channel  18  sensed by one or more sensor(s) (e.g., a pressure sensor, etc.) in communication with fluid channel  18 . The diagnostic parameters may be determined by valve controller  26  and stored in a non-volatile memory  37  or other memory accessible by valve controller  26 . The diagnostic parameters may include, but are not limited to, a total number of operational cycles, a fuel usage parameter, one or more fault history parameters, one or more user or factory or other setting parameters, self diagnostic check parameters, fault parameters and/or other similar or dissimilar parameters, as desired. The communicated valve condition(s) or measure(s) related to the valve condition(s) may be determined by valve controller  26  or one or more remote devices. Illustrative valve conditions and measures related to valve conditions may include, but are not limited to: high fuel pressure conditions, low fuel pressure conditions, valve closure conditions, valve leak conditions, safety event condition, and/or other similar or dissimilar valve conditions and/or outputs. 
     In addition to communication interface  110  being configured to output information to a device located adjacent or remote from valve assembly  10 , communication interface  110  may be configured to receive one or more inputs from the remote device or an adjacently positioned device. Illustrative inputs may include, but are not limited to: an acknowledgement of reception of one or more of the valve conditions, a user setting, a system setting, a valve command, control signals (e.g. firing rate control signals) and/or other similar or dissimilar input. 
     In some instances, valve controller  26  may communicate through the I/O interface or communication interface  110  with a remotely located output block  46 , where output block  46  may display and/or output a determined measure related to fluid flow rate through fluid channel  18 , sometimes along with other data, information and controls sent from valve controller  26  (see, for example,  FIGS. 9 and 10 ). For example, the output block  46  may display a measure of cumulative fuel flow over a predetermined period of time and/or instantaneous fuel flow through the valve assembly  10 . Output block  46  may include a display and/or other remote systems, and microcontroller  36  may be configured to send measures to a device control system  60  or building automation system or overall system controller  50  of output block  46  for further monitoring and/or analysis. As discussed, the I/O interface may include a wired and/or wireless interface between valve controller  26  (e.g., microcontroller  36 ) and output block  46  systems (e.g., building automation system or overall system controller  50 , combustion appliance management system  60 , handheld device, laptop computer, smart phone, etc.), where the connection between valve controller  26  may or may not be made with communication link  100  (e.g., communication link  100  could, but need not be, the one and only one communication link). 
     In an illustrative operation, valve controller  26  may be utilized in a method for communicating information between valve assembly  10  and a combustion appliance controller  60 , where the combustion appliance controller  60  may be associated with a combustion appliance (e.g., a device separate from, and possibly remotely relative to valve assembly  10 ) for which valve assembly  10  may control a flow of fuel. In some cases, the valve controller  26  may receive one or more control signals such as, a firing rate control signal indicative of a desired firing rate, from the combustion appliance controller  60 . The valve controller  26  may store the firing control signals in a non-volatile memory  37 , or other memory, of valve controller  26 , and, in some cases, may compare the firing rate control signals to a data table storing a relationship between firing rate and flow rate stored in the memory. The valve controller  26  may use the firing rate control signal and the relationship previously stored in the memory  27  to determine a measure related to fuel flow through the valve assembly  10 . For example, the valve controller  26  may determine a cumulative fuel flow over a predetermined period of time and/or an instantaneous fuel flow over time. In some cases, the valve controller may output this information to the combustion appliance controller  60  (or other controller or device) across a communication link or bus  100  connected to a communications interface  110 . 
     In addition to or alternatively, valve controller  26  may detect, with one or more sensors (e.g., pressure sensor assembly  24 ), one or more sensed parameters within fluid channel  18  of valve assembly  10 . The sensed parameter may be stored in a non-volatile memory  37 , or other memory, of valve controller  26 . Valve controller  26  may determine one or more valve conditions (e.g., a safety event condition) based on the one or more sensed parameters. For example, valve controller  26  may compare the one or more sensed parameters to a threshold parameter to determine one or more valve conditions. If one or more valve conditions have been determined, valve controller  26  may be configured to send information that may be related to the one or more determined valve conditions from valve assembly  10  to the combustion appliance controller  60  (or other controller or device) across a communication link or bus  100  connected to a communications interface  110 . 
     In one example, upon receiving one or more determined valve conditions, such as a safety event condition, combustion appliance controller  60  (or other controller or device) may be configured to open safety switch  70 , such that power to a valve control signal that is coupled to one or more valve actuators  30  is cut, thereby automatically closing one or more valve ports  20  (e.g., closing valve sealing member(s)  22  of valve port(s)  20 ). In some cases, safety switch  70  may be controlled by an algorithm in combustion appliance controller  60 , where an output of the algorithm is affected by information passed via the communication link  100 . Additionally, or in the alternative, other feedback signals may affect an output of the algorithm, where the other feedback signals may or may not be passed via the communication link  100  and may or may not originate from valve assembly  10 . 
     In other illustrative operations, a low gas pressure/high gas pressure event may be reported from valve controller  26  to combustion appliance controller  60 . In response to receiving a reported low gas pressure/high gas pressure event, combustion appliance controller  60  may be configured to open safety switch  70 . Further, in cases where a proof of closure event is reported to combustion appliance controller  60  prior to ignition of the combustion appliance, an ignition sequence may not be started. In certain other instances where a Valve Proving System (VPS) sequence test is being performed, a combustion appliance controller  60  may use reported results of the VPS sequence test to make an evaluation. For example, if in the evaluation of the VPS test it were determined that a valve was leaking, the appliance controller  60  might be programmed to open safety switch  70 , to initiate a safety lockout, to initiate an alarm, and/or to take any other similar or dissimilar measure. 
     In other scenarios, valve assembly  10  may be used as a control valve and in that case, valve controller  26  may send a signal to combustion appliance controller  60  indicative of a valve position, and combustions appliance controller  60  may respond accordingly. For example, the valve assembly may actuate a valve member between a first position and a second position to control a flow rate of fluid through the fluid channel and thus, ultimately, a firing rate of the combustion appliance  60 . These other scenarios, for example, may be applied in parallel positioning system applications, low fire switch applications, auxiliary switch applications, etc. Additionally, it is contemplated that valve controller  26  may interact with remote devices in other similar and dissimilar manners within the spirit of this disclosure. 
     Pressure block or pressure sensor assembly  24  may be included in flow module  28 , as seen in  FIGS. 9 and 10 , and/or pressure sensor assembly  24  may be at least partially separate from flow module  28 . Pressure sensor assembly  24  may be configured to continuously or non-continuously sense pressure or a measure related to pressure upstream and/or downstream of a characterized port and/or along other portions of fluid channel  18 . Although pressure sensor assembly  24  may additionally, or alternatively, include a mass or volume flow meter to measure a flow of fluid through fluid channel  18 , it has been contemplated that such meters may be more expensive and difficult to place within or outside the valve assembly  10 ; thus, a useful, relatively low cost alternative and/or additional solution may include placing pressure sensors  38 ,  42 ,  43 ,  44  and/or other pressure sensors within, about and/or integrated in valve body  12  of valve assembly  10  to measure the fluid flow through fluid channel  18 , the pressures at the input and output ports, and/or other similar or different pressure related measures. Pressure sensors  38 ,  42 ,  43 ,  44  may include any type of pressure sensor element. For example, the pressure sensor element(s) may be MEMS (Micro Electro Mechanical Systems) pressure sensors elements or other similar or different pressure sensor elements such as an absolute pressure sense element, a gauge pressure sense element, or other pressure sense element as desired. Example sense elements may include, but are not limited to, those described in U.S. Pat. Nos. 7,503,221; 7,493,822; 7,216,547; 7,082,835; 6,923,069; 6,877,380, and U.S. patent application publications: 2010/0180688; 2010/0064818; 2010/00184324; 2007/0095144; and 2003/0167851, all of which are hereby incorporated by reference. 
     In some cases, pressure sensor assembly  24  may include a differential pressure sensor  38  for measuring a differential pressure drop across a characterized valve port  20 , or across a different characterized port, as seen in  FIG. 9 . A pressure sensor assembly  24  including a differential pressure sensor  38 , may be exposed to both a first pressure  38   a  upstream of a characterized valve port and a second pressure  38   b  downstream of the characterized valve port. Differential pressure sensor  38  may send a measure related to the sensed differential pressure to the microcontroller  36  of valve controller  26 , as seen from the diagram of  FIG. 9 . Microcontroller  36  may be configured to monitor the differential pressure across the characterized port with the differential pressure measures sensed by differential pressure sensor  38 . 
     Alternatively, or in addition, an illustrative pressure sensor assembly  24  may include one or more first pressure sensors  42  upstream of a characterized valve port and one or more second pressure sensors  43  downstream of the characterized valve port, where first and second pressure sensors  42 ,  43  may be in fluid communication with fluid channel  18  and may be configured to sense one or more measures related to a pressure upstream and a pressure downstream, respectively, of the characterized valve port, as seen in  FIG. 10 . Where a second valve port (e.g., second valve port  20   b ) may be positioned downstream of a first characterized valve port (e.g. first valve port  20   a ) and forming an intermediate volume  19  between first and second valve ports, pressure sensor assembly  24  may include one or more third pressure sensors  44  in fluid communication with the intermediate volume  19 , which may sense one or more measures related to a pressure in the intermediate volume  19 . Where two characterized ports are utilized, first pressure sensors  42  may be upstream of both characterized ports, second pressure sensors  43  may be downstream of both characterized ports, and third pressure sensors  44  may be downstream from the first characterized port and upstream from the second characterized, but this is not required (e.g., first and second pressure sensors  42 ,  43  may be used to estimate the pressure drop across the valves). Additionally, or in the alternative, one or more differential pressure sensors  38  may be utilized to estimate the pressure drop across the first characterized port and/or the second characterized port. It is further contemplated that valve ports  20  may not be characterized ports. 
     Pressure sensors  42 ,  43 ,  44  may be configured to send each of the sensed measure(s) directly to microcontroller  36 . Microcontroller  36  may be configured to save the sensed measures and/or related information to a non-volatile memory  37 , and may perform one or more analyses on the received sensed measures. For example, microcontroller  36 , which may be a portion of flow module  28  and/or valve controller  26 , may determine a measure that is related to a fluid flow rate through the fluid path based, at least in part, on the received sensed measures related to pressure upstream of the characterized port and on the received sensed measures related to pressure downstream of the characterized port. In some cases, microcontroller  26  may determine a measure that is related to a fluid flow rate through the fluid path based, at least in part, on a previously determined relationship between two or more flow rates and the sensed measures stored in the memory  37  during calibration. 
     Where a valve assembly  10  includes one or more valve ports  20 , pressure sensor assembly  24  may include first pressure sensor  42  positioned upstream of first valve port  20   a  at or downstream of inlet port  14 , as seen in  FIG. 11 . In addition, or alternatively, pressure sensor assembly  24  may include a second pressure sensor  43  positioned downstream of second valve port  20   b  at or upstream from outlet port  16 . Valve assembly  10  may further include one or more third pressure sensors  44  downstream of first valve port  20   a  and upstream of second valve port  20   b . Pressure sensors  42 ,  43 ,  44  may be configured to sense a pressure and/or a measure related to the pressure in fluid channel  18 , and to communicate the sensed measures to valve controller  26 , which is physically coupled to or positioned within valve body  12 . Where multiple pressure sensors  42 ,  43 ,  44  exist at or near one or more location (e.g., upstream of valve ports  20 , intermediate of valve ports  20 , downstream of valve ports  20 , etc.) along fluid channel  18 , at least one of the multiple pressure sensors may be configured to sense pressures over a pressure sub-range different from a sub-range over which at least one other of the multiple pressure sensors at the location may be configured to sense pressure, but this is not required. In some cases, and as shown in  FIG. 8 , the various pressure sensors may be mounted directly to a corresponding circuit board, such that when the circuit board is mounted to the valve body  12 , the pressure sensor is in fluid communication with a corresponding fluid port in the valve body  12 . 
     In some instances, such arrangements of pressure sensors  38 ,  42 ,  43 ,  44  within valve assembly  10 , along with the connection between valve controller  26  and pressure sensors  38 ,  42 ,  43 ,  44  may be used to emulate functions of high gas pressure (HGP) and low gas pressure (LGP) switches, which traditionally require wires and further housings extending to and from and/or attached to valve body  12 . When the electronics and elements of valve assembly  10  are configured to emulate LGP/HGP switches, gas-valve wiring connections and interactions may be at least partially avoided, eliminated or simplified. In some instances, such configuration of valve controller  26  and pressure sensors  38 ,  42 ,  43 ,  44  may reduce manual operations (e.g., manually adjusting a mechanical spring or other device of conventional high gas pressure (HGP) and low gas pressure (LGP) switches), and allow for a more precise fitting with the electronics of valve assembly  10 . 
     In some cases, pressure sensor assembly  24  may include one or more absolute pressure sensors  54  in communication with microcontroller  36 . Absolute pressure sensor  54  may sense an atmospheric pressure adjacent gas valve assembly  10 , and may be configured to communicate and transfer data related to the sensed atmospheric pressure to microcontroller  36 . Microcontroller  36  may take into account the atmospheric pressure from the absolute pressure sensor  54  when determining the flow rate of fluid flowing through the characterized port and/or an estimate of fuel consumption by an attached appliance and/or when determining threshold values. Other sensors may be included in valve assembly  10 , for example, one other type of sensor may be a barometric pressure sensor. 
     As discussed, valve assembly  10  and the flow module  28  thereof may include temperature sensor(s)  34 , as seen in  FIGS. 9-11 . Temperature sensor  34  may be positioned within valve body  12  so as to be at least partially exposed to fluid channel  18  and configured to sense a temperature of a fluid (e.g., gas or liquid) flowing through fluid channel  18  and/or any other temperature in fluid channel  18 . Temperature sensor  34  may have a first temperature sensor  34   a  at least partially exposed to fluid channel  18  upstream of a characterized valve port, and/or a second temperature sensor  34   b  at least partially exposed to fluid channel  18  downstream of the characterized valve port, as seen in  FIGS. 9 and 10 . When there is a first valve port and a second valve port (e.g., valve ports  20   a ,  20   b ), there may be a third temperature sensor  34   c  in fluid communication with intermediate volume  19  between the first and second characterized valve ports, if desired. The sensed temperature measure may be used by flow module  28  to, for example, compensate, correct, or modify a determined measure (e.g., a density of a fluid) that is related to, for example, a fluid flow rate of fluid flowing through fluid channel  18 , which may help improve the accuracy of the flow rate calculation which, in turn, may improve the accuracy of an fuel consumption determination. In operation, temperature sensor  34  (e.g., any or all of temperatures sensors  34   a ,  34   b ,  34   c ) may communicate a sensed temperature measure directly or indirectly to valve controller  26  and/or a non-volatile memory  37  of valve controller  26  (e.g., memory in a microcontroller  36  or memory in another location) and/or flow module  28 . Valve controller  26  may, in turn, utilize the sensed temperature to help increase the accuracy of a determined flow rate of fluid passing through a characterized port and/or increase the accuracy of a calculated fluid and/or fuel consumption quantity, as desired, and store the calculated flow rate of fluid passing through a characterized port and/or the calculated fluid and/or fuel consumption quantity in the non-volatile memory  37 . Additionally, or in the alternative, in some instances pressure sensors  38 ,  42 ,  43 ,  44  may utilize built-in temperature sensors that are used to internally compensate the pressure sensor over the operating temperature range. In such instances, the temperature reading may be accessible at the pressure sensor output (e.g., a digital communication bus) or at another location. 
     Flow module  28  of valve assembly  10  may further include a position sensor system that may be configured to continuously or discontinuously sense at least one or more of an axial position, a rotary position, and/or a radial position, of valve sealing member  22  within or about fluid valve port  20 . In some cases, position sensor system may include more than one position sensors  48 , such that each position sensor  48  may monitor a sub-range of a valve&#39;s total travel. Moreover, position sensor system may be utilized as a proof of closure switch system. Position sensor(s)  48  of the position sensor system may be situated or positioned in valve body  12  at or about a valve port  20 . For example, and in some instances, position sensor(s)  48  may be fluidly isolated from fluid channel  18  (e.g., fluidly isolated from fluid channel  18  by valve body  12 ), and radially spaced from an axis upon which a valve sealing member(s)  22  may axially and/or rotationally translate between a closed position and an open position, as seen in  FIGS. 14-17 . 
     An illustrative gas valve assembly  10  may include a first valve port  20   a  and a second valve port  20   b  (see  FIG. 7 ), and a first position sensor  48   a  monitoring first valve sealing member  22   a  and a second position sensor  48   b  monitoring second valve sealing member  22   b , where position sensors  48   a ,  48   b  may be separate devices or may share an enclosure and/or other parts. In the illustrative instance, the first position sensor  48   a  may be fluidly isolated from fluid channel  18  and radially spaced from a first axis of first valve port  20   a , and the second position sensor  48   b  may be fluidly isolated from fluid channel  18  and radially spaced from a second axis of second valve port  20   b  (see  FIGS. 14-17 ). 
     As discussed above, position sensor  48  may be configured to detect a measure that is related to whether valve sealing member  22  is in an open or closed position and/or a measure related to an intermediate position of valve sealing member  22  within fluid valve port  20 . In one example, position sensor(s)  48  may be configured to provide a proof of closure (POC) sensor(s) for valve port(s)  20  (e.g., first valve port  20   a  and/or second valve port  20   b ). 
     Where valve sealing member(s)  22  have a range of travel (e.g., rotationally and/or axially) within valve port(s)  20 , position sensor(s)  48  may be configured to sense a current position of valve sealing member(s)  22  anywhere along the range of travel of valve sealing member(s)  22 . Position sensor  48  may then send (e.g., through electronic or other communication) sensed positioning data of the measure related to the position of valve sealing member  22  to determining block and/or microcontroller  36  and/or a non-volatile memory  37  of valve controller  26  and/or flow module  28 , where microcontroller  36  may be configured to monitor the axial position of valve sealing member  22  within valve port  20  through position sensor system  48 . In some cases, valve sealing member  22  may be moved between a first position and a second position to control a flow rate of the fluid through the fluid channel  18  and thus, a firing rate of a downstream combustion appliance fluidly connected to the valve assembly  10 . The valve controller  26  may receive a feedback control signal from the combustion appliance that is indicative of a firing rate and may store the control signal in the memory  37 . 
     In some instances, valve controller  26  may include an electronic circuit board and a wired or wireless communication link  100  may facilitate communication between position sensor(s)  48  and the electronic circuit board or other device of valve controller  26 . Valve controller  26  may be configured to further pass on positioning information to remote devices through communication lines (e.g., communication link  100 ) and/or display positioning data of valve sealing member  22  on one or more displays  76  attached to valve assembly  10  and/or remote devices, as seen in  FIG. 13 . Valve controller  26  may indicate a closed or open position of valve sealing member  22  or a degree (e.g., 10%, 20%, 30%, etc.) of an opening of valve sealing member  22  with one or more visual indicators on or comprising display(s)  76 , as seen in  FIG. 13 , such as one or more light emitting diodes (LEDs) acting as a visual indication of a valve state and/or position, liquid crystal displays (LCDs), a touch screen, other user interfaces and/or any other display interfacing with or displaying information to a user. 
     In some instances, the position sensor system may include one or more switches  64  (e.g., a first switch  64   a  and a second switch  64   b , where switch(es)  64  may be or may include relays or other switch types such as FETs, TRIACS, etc.) having one or more switched signal paths  66  and one or more control inputs  68  (e.g., a first control input  68   a  and a second control input  68   b ), as seen in  FIG. 13 . Illustratively, one switch  64  may be utilized for multiple position sensors  48 , or more than one switch  64  may be utilized for multiple position sensors (e.g., in a 1-1 manner or other manner), as desired. Control input  68  may set the state of switched signal paths  66  to a first state or a second state or another state, as desired. As depicted in  FIG. 13 , valve controller  26  may be coupled to position sensor(s)  48 , and may control input  68  of switch  64 , where both valve controller  26  and position sensors  48  may be isolated from fluid communication with fluid channel  18 . In some instances, valve controller  26  may be configured to set the state of switched signal path  66  to the first state when first position sensor  48   a  senses that a first valve port  20   a  is not closed or first valve sealing member  22   a  is not in a closed position, and to a second state when position sensor  48  senses that a first valve port  20   a  is closed or first valve sealing member  22   a  is in a closed position. Similarly, valve controller  26  may be configured to set the state of switched signal path  66  to the first state when second sensor  48   b  senses that second valve port  20   b  is not closed or second valve sealing member  22   b  is not in a closed position, and to a second state when position sensor  48  senses that a second valve port  20   b  is closed or second valve sealing member  22   b  is in a closed position. In the alternative, valve controller  26  may be configured to set the state of switched signal path  66  to the first state when at least one of the first and second sensors valve ports  20   a ,  20   b  are not closed or at least one of the first and second valve sealing members  22   a ,  22   b  are not in a closed position, and to a second state when position sensor  48  senses that both first and second valve ports  20   a ,  20   b  are closed or both first and second valve sealing members  22   a ,  22   b  are in closed positions. Similar or identical or different processes, as desired, may be utilized for each position switch  64  and control input  68 . 
     Illustratively, valve sealing member(s)  22  may include a sensor element  80 , and position sensor(s)  48  may include one or more transducer or field sensors  82 . For example, valve sealing member(s)  22  may include a sensor element  80  (e.g., a magnet when using a field sensor  82 , a ferrous core when using a linear variable differential transformer (LVDT)  84 , or other sense element, and/or similar or dissimilar indicators) secured relative to and translatable with valve sealing member(s)  22 . Position sensor(s)  48  may include one or more field sensors  82  (e.g., magnetic field sensors, a LVDT  84 , Hall Effect sensors or other similar or dissimilar sensors), as seen in  FIGS. 14-15 . Field sensor  82  may be positioned within valve body  12  or may be positioned exterior to valve body  12  and radially spaced from a longitudinal axis of valve port(s)  20  and/or valve sealing member(s)  22 . Position sensor(s)  48  may be positioned so as to be entirely exterior to fluid channel  18 . The meaning of entirely exterior of fluid channel  18  may include all position sensors  48  and all electronics (e.g., wires, circuit boards) connected to position sensor(s)  48  being exterior to fluid channel  18 . Where position sensor(s)  48  includes an LVDT, the LVDT may be positioned concentrically around and radially spaced from valve sealing member(s)  22 , as shown in  FIG. 15 , and/or the axis of LVDT may be spaced radially and parallel from the valve sealing members  22 . 
     In some cases, a strain gauge  86 , as depicted in  FIG. 16 , or other electromechanical sensor may also be utilized to sense a position of valve sealing member  22  within an interior of fluid channel  18  from a position fluidly exterior of fluid channel  18  by sensing a strain level applied by spring  31  in communication with valve sealing member  22 . Alternatively, or in addition, valve sealing member(s)  22  may include one or more visual indicators  88  (e.g., a light reflector or other visual indicators), and position sensor(s)  48  may include one or more optical sensors  90 , as seen in  FIG. 17 , where visual indicators may be any indicators configured to be viewed by optical sensors through a transparent window  87  sealed with an o-ring or seal  89  or through another configuration, such that optical sensors  90  may determine at least whether valve sealing member(s)  22  is/are in a closed or open position. Where a visual position indicator  88  is utilized, and in some cases, a user may be able to visually determine when valve sealing member(s)  22  is not in a closed position. 
     As may be inferred from the disclosure, position sensor  48  may in some instances operate by detecting a position of a valve sealing member  22  and/or optionally valve stem  92  or the like within a valve assembly  10  having a valve body  12 , where valve sealing member  22  may be translatable with respect to valve port  20  of valve body  12  along a translation or longitudinal axis “A” within a valve port  20 . In some cases, sensor element  80 , affixed relative to valve sealing member  22 , may be positioned within the interior of valve body  12  and may optionally fluidly communicate with fluid channel  18 ; however, position sensor  48  may be isolated from fluid channel  18  and/or positioned exterior to valve body  12 . In an illustrative embodiment, valve sealing member  22  may be positioned at a first position within an interior of valve port  20  along translation axis A. The first position of the valve sealing member  22  may be sensed with position sensor  48  by sensing a location of a sensor element  80  secured relative to valve sealing member  22  with position sensor  48 . Then, position sensor  48  may automatically or upon request and/or continuously or discontinuously, send the sensed location and/or open or closed state of valve sealing member  22  to the valve controller  26 . 
     It is contemplated that valve controller  26  may electronically calibrate the closed position of valve sealing member  22  and/or valve stem  92 . Such a calibration may store the position of the valve sealing member  22  and/or valve stem  92  when the valve sealing member  22  and/or valve stem  92  is in a known closed position (e.g. such as during installation of the valve assembly  10 ). During subsequent operation, the position of the valve sealing member  22  and/or valve stem  92  can be compared to the stored position to determine if the valve sealing member  22  and/or valve stem  92  is in the closed position. A similar approach may be used to electronically calibrate other positions of the valve sealing member  22  and/or valve stem  92  (e.g. fully open position, or some intermediate position), as desired. 
     Fuel Rate Monitor 
     In operation, valve assembly  10  may be utilized to measure a flow rate of fluid flowing through a characterized port (e.g., valve port  20  or other port). As discussed above, the measuring method may include utilizing a microcontroller  36  or the like to monitor (e.g., monitoring sensed measures, monitoring control signals, set-points, and user settings, etc.) a differential pressure across a characterized valve port which may be continuously or discontinuously monitored by pressure sensor assembly  24 , monitoring (e.g., monitoring sensed/feedback measures, monitoring control signals (e.g. firing rate control signals), set-points and user settings, etc.) a position of a valve sealing member  22  within the characterized valve port which may be continuously or discontinuously monitored by position sensor  48 , and/or determining a flow rate of the fluid flowing through the characterized port with the microcontroller  36  from the monitored differential pressure, and in some cases, the monitored position of the valve sealing member  22 . 
     To facilitate determining the flow rate of fluid flowing through the characterized port, microcontroller  36  may utilize a valve&#39;s opening curves stored in a memory  37 . In some cases, the characterized port may be characterized at various flow rates and/or across various valve positions, including fully open and fully closed and multiple valve positions in between fully open and fully closed, to identify a relationship between a measured pressure drop across the characterized port and the flow rate through the gas valve. Of course, when the valve only switches between a fully closed position and a fully open position, the characterized port need not be characterized over various open positions; just over the fully open position and fully closed position. In some cases, the relationship may be stored in a non-volatile memory  37  of the gas valve assembly  10 . 
     Through the use of valve opening curves, calibration curves, and/or other similar or different data and/or algorithms, microcontroller  36  may determine a flow rate for any combination of sensed pressure drop and sensed valve sealing member  22  positions. As further detailed herein, it is contemplated that temperature, atmospheric pressure, inlet pressure, outlet pressure, excess air ratio, flue gas oxygen concentrations, and/or other sensed parameters may be used to help increase the accuracy of the determined flow rate, if desired. 
     Microcontroller  36  may be configured to continuously monitor the differential pressure across the characterized port, and in some cases continuously monitor the position of the valve sealing member  22 , in such a manner as to be configured to continuously determine the flow rate of the fluid flowing through the valve port. Continuously monitoring the differential pressure(s) and in some cases the positioning of the valve sealing member  22 , and continuously determining the flow rate of fluid flowing through the characterized port, may facilitate the microcontroller  36  continuously tracking, reporting, and/or outputting an instantaneous flow rate of the fluid flowing through the characterized port and/or to continuously tracking, reporting, and outputting a cumulative flow volume of the fluid (integral of the flow rate over time) flowing through the characterized port over a given period of time. An average flow rate of fluid flowing through the characterized port may be determined from the instantaneous flow rates of the fluid over time. In addition, microcontroller  36  may send one or more of the tracked and reported instantaneous flow rates and/or the cumulative flow volume from microcontroller  36  to a system controller  50  and/or an appliance controller  60  via a communication link  100 , if desired, and the reported instantaneous flow rates and/or the cumulative flow volume and/or other data may be read out at the local valve controller display  76 , appliance display  62  and/or system display  52 . 
     In addition to taking into consideration differential pressure across a characterized port, and in some cases the positioning of valve sealing member  22  (e.g. when intermediate open positions are used), microcontroller  36  may consider measures from one or more other sensors that sense characteristics within or about fluid channel  18  or other resources. For example, microcontroller  36  may consider one or more measures related to a temperature in fluid channel  18  sensed by temperature sensor(s)  34  (e.g., temperature may be used to correct/calculate a fluid flow rate), one or more measures related to an absolute pressure about fluid channel  18  sensed by an absolute pressure sensor  54  (e.g., absolute pressure may be used to correct/calculate flow rate of a fluid), and/or other measures sensed by other sensors or received from other sources, as desired. 
     It is also contemplated that microcontroller  36  may take into consideration the altitude of the fluid channel  18  with respect to sea level or another baseline measure when determining a flow rate of fluid through fluid channel  18 . Altitude may be continuously or discontinuously sensed by an altimeter on or adjacent or remotely located from valve assembly  10  and/or an altitude may be preset within microcontroller  36  or entered at any time prior to or during or after installation of the valve assembly  10 . Also, it is contemplated that a Wobbe index associated with the fluid flowing through fluid channel  18  may be stored and utilized. Utilization of a Wobbe index may facilitate reporting out of fluid flow rates through fluid channel  18  by microcontroller  36  in units of energy per time (e.g., BTU/hour for indicating fuel consumption), rather than reporting a volumetric or mass flow measure. Such consideration of further characteristics (including characteristics not listed) related to fluid channel  18  may allow for determining more accurate flow rate measures of the fluid flowing through fluid channel  18 , as the utilizing of further characteristics may have the ability to reduce assumptions in known flow equations/algorithms utilized by microcontroller  36 . 
     Additionally, or alternatively, valve assembly  10  may be utilized to determine an instantaneous and/or cumulative flow of fluid through the characterized port based on one or more monitored control signals such as, for example, a firing rate signal received at the valve controller  36  indicative of a desired firing rate. The microcontroller  36  can determine fuel consumption and hence, an estimate of energy consumption, based on firing rate and flow rate. For example, in some cases, during calibration of the valve assembly  10 , a relationship may be established between flow rate and firing rate. The relationship may be calibrated using a measured flow rate of fuel through the characterized port (e.g. valve port  20  o other port) at each of two or more desired firing rates over a range of firing rates. In some instances the firing rate may correspond to ON and OFF if the combustion appliance is not modulating. Additionally, in certain cases, the relationship my include interpolating between two or more desired firing rates at which the flow rates of fuel through the characterized ports were measured. The relationship is stored in the memory  37  from which it may be retrieved by the microcontroller  36  and utilized to determine a measure related to fuel consumption of a combustion appliance fluidly connected to and located downstream of the valve assembly  10 . The microcontroller  37  may monitor the firing rate signals, and using the relationship previously stored in the memory  37 , may determine the flow rate through the valve assembly  10  by interpolating the flow rate between two or more firing rates. The fluid flow rate can be reported in units of energy/time using the Wobbe index associated with the fluid flowing through the valve assembly  10  stored in the memory  37 . As such, the valve assembly  10  can monitor, track and report the instantaneous and cumulative fuel consumption over a predetermined period of time. 
     As discussed herein, microcontroller  36  may consider measures from one or more other sensors that sense characteristics within or about fluid channel  18  or other resources. For example, microcontroller  36  may consider one or more measures related to a fluid pressure in fluid channel  18  sensed by a fluid pressure sensor sensor(s)  34 , one or more measures related to an absolute pressure about fluid channel  18  sensed by an absolute pressure sensor  54  (e.g., absolute pressure may be used to correct/calculate flow rate of a fluid), one or more measures related to an ambient pressure in the fluid channel sensed by an ambient pressure sensor, temperature in the fluid channel  18  as measured by a temperature sensor, flue gas oxygen concentration, excess air ratio (λ), and/or other measures sensed by other sensors or received from other sources, as desired. Such consideration of further characteristics may allow for determining more accurate flow rate measures of the fluid flowing through fluid channel  18  and as a result, fuel consumption by an appliance fluidly coupled to the valve assembly  10 , as the utilizing of further characteristics may have the ability to reduce assumptions and enhance the accuracy in known flow equations/algorithms utilized by microcontroller  36 . 
     In some instances, the determination of fuel consumption by microcontroller  36  may be enhanced or improved by correcting for lambda (λ) also referred to herein as excess air ratio. The correction factor for excess air ratio may be applied to data supplied by the valve manufacturer and stored in the memory  37  or to the flow rate vs. firing rate relationship data generated during commissioning and/or calibration of the valve assembly  10  and also stored in the memory  37 . In some cases, lambda measured in the field (λ actual ) may differ from lambda assumed by the appliance manufacturer (λ referential ), which may be a known value and which may be stored in the memory  37  at the time of manufacture of the valve assembly  10  or during commissioning. In some cases, lambda measured in the field (λ actual ) may be derived from flue gas oxygen concentration if a flue gas oxygen sensor is present in the system. Lambda measured in the field (λ actual ) may be then used to determine a corrected volume of fuel consumed for a more accurate determination of fuel consumption. 
     Exemplary equations for determining a corrected fuel consumption V fuel   _   corrected , are provided below, where: V fuel   _   corrected , is the total volume of fuel consumed corrected for lambda; V fuel   _   actual  is the volume of fuel consumed (as discussed herein, this may be determined based on a relationship of flow rate vs. differential pressure across the valve port  20  and/or firing rate vs. flow rate); M fuel  is the molar weight of the fuel flowing through the fluid channel  18 ; ρ air , is the density of air; p air  is the absolute pressure of air; p fuel  is the absolute pressure of the fuel; T air  is the temperature of air; T gas  is the temperature of the gas R is the universal gas constant; AF stoch   _   molar  is the stoichiometric air/fuel ratio; λ actual  is the excess air ratio measured in the field; λ referential  is the excess air ratio referential value; and ρ_   fuel    is the density of the fuel. 
     For a solid or liquid fuel, Equation 1 may be utilized to determine a corrected volume of fuel consumed by a combustion appliance fluidly connected to the valve assembly  10 . 
     
       
         
           
             
               
                 
                   
                     
                       V 
                       . 
                     
                     fuel_corrected 
                   
                   = 
                   
                     
                       
                         ( 
                         
                           
                             
                               M 
                               fuel 
                             
                             · 
                             
                               p 
                               air 
                             
                           
                           + 
                           
                             R 
                             · 
                             
                               AF 
                               stoch_molar 
                             
                             · 
                             
                               λ 
                               actual 
                             
                             · 
                             
                               T 
                               air 
                             
                             · 
                             
                               ρ 
                               fuel 
                             
                           
                         
                         ) 
                       
                       
                         ( 
                         
                           
                             
                               M 
                               fuel 
                             
                             · 
                             
                               p 
                               air 
                             
                           
                           + 
                           
                             R 
                             · 
                             
                               AF 
                               stoch_molar 
                             
                             · 
                             
                               λ 
                               referential 
                             
                             · 
                             
                               T 
                               air 
                             
                             · 
                             
                               p 
                               fuel 
                             
                           
                         
                         ) 
                       
                     
                     ⁢ 
                     
                       
                         V 
                         . 
                       
                       fuel_actual 
                     
                   
                 
               
               
                 
                   Equation 
                   ⁢ 
                   
                       
                   
                   ⁢ 
                   1 
                 
               
             
           
         
       
     
     For a gas fuel, Equation 2 may be utilized to determine a corrected volume of fuel consumed by a combustion appliance fluidly connected to the valve assembly  10 . 
     
       
         
           
             
               
                 
                   
                     
                       V 
                       . 
                     
                     gas_corrected 
                   
                   = 
                   
                     
                       
                         ( 
                         
                           
                             
                               T 
                               gas 
                             
                             ⁢ 
                             
                               p 
                               air 
                             
                           
                           + 
                           
                             
                               
                                 AF 
                                 stoch_molar 
                               
                               · 
                               
                                 λ 
                                 actual 
                               
                               · 
                               
                                 T 
                                 air 
                               
                             
                             ⁢ 
                             
                               p 
                               gas 
                             
                           
                         
                         ) 
                       
                       
                         ( 
                         
                           
                             
                               T 
                               gas 
                             
                             ⁢ 
                             
                               p 
                               air 
                             
                           
                           + 
                           
                             
                               
                                 AF 
                                 stoch_molar 
                               
                               · 
                               
                                 λ 
                                 referential 
                               
                               · 
                               
                                 T 
                                 air 
                               
                             
                             ⁢ 
                             
                               p 
                               air 
                             
                           
                         
                         ) 
                       
                     
                     ⁢ 
                     
                       
                         V 
                         . 
                       
                       gas_actual 
                     
                   
                 
               
               
                 
                   Equation 
                   ⁢ 
                   
                       
                   
                   ⁢ 
                   2 
                 
               
             
           
         
       
     
     Neglecting pressure and assuming density of air, ρ air , is equal to the gas density, ρ_   gas    or, alternatively, assuming the pressure of the air is equal to the pressure of the gas, a third equation, Equation 3, may be utilized. 
                       V   .     gas_corrected     =         (       T   gas     +       AF   stoch_molar     ·     λ   actual     ·     T   air         )       (       T   gas     +       AF   stoch_molar     ·     λ   referential     ·     T   air         )       ⁢       V   .     gas_actual               Equation   ⁢           ⁢   3               
Alternatively, in some cases, temperature may be neglected.
 
                       V   .     gas_corrected     =         (     1   +       AF   stoch_molar     ·     λ   actual         )       (     1   +       AF   stoch_molar     ·     λ   referential         )       ⁢       V   .     gas_actual               Equation   ⁢           ⁢   4               
Gas pressure and temperature may be neglected where a temperature and/or pressure sensor are unavailable.
 
     Table 1, presented below, summarizes the various conditions under which lambda may be used to determine a corrected volume of fuel consumption. Additionally,  FIGS. 18-21  show different curves illustrating the effect of lambda measured in the field (λ actual ) on the relationship between firing rate and flow rate. The curves shown in the examples provided by  FIGS. 18-21  are exemplary of those curves that may be stored in the memory  37  during commissioning and that may be utilized to determine a flow rate and hence, an estimated fuel consumption, based on firing rate. 
     
       
         
           
               
               
             
               
                   
                 TABLE 1 
               
             
            
               
                   
                   
               
               
                   
                 Fuel flow sensor available or fuel 
               
               
                   
                 flow dependency on FR constructed* 
               
               
                   
                 during commissioning 
               
            
           
           
               
               
               
            
               
                   
                   
                 No - manufacture 
               
               
                   
                 Yes 
                 info used. 
               
               
                   
                   
               
            
           
           
               
               
               
            
               
                 Lambda at field - fixed 
                 Correction not 
                 Correction needed 
               
               
                 λ actual  = λ atField(commissioning)  = 
                 needed 
                 (see FIG. 18) 
               
               
                 const 
                 (included in gas 
               
               
                   
                 flow dependency) 
               
               
                 Lambda as function of FR 
                 Correction not 
                 Correction needed 
               
               
                 λ actual  = f(FR) 
                 needed 
                 (see FIG. 19) 
               
               
                   
                 (included in gas 
               
               
                   
                 flow dependency) 
               
               
                 Lambda as function of FR 
                 Correction needed 
                 Correction needed 
               
               
                 and time 
                 (see FIG. 21) 
                 (see FIG. 20) 
               
               
                 λ actual  = f(FR, t) 
               
               
                   
               
               
                 *e.g. for fuel = gas: using pressure drop across the burner orifice (and deriving the gas flow using manufacturer&#39;s burner data and Bernoulli&#39;s equation) 
               
            
           
         
       
     
     Turning now to more specific examples, in one instance, if the fuel flow dependency on firing rate cannot be constructed or measured during commissioning (the fuel flow dependency for a gaseous fuel can be constructed using pressure drop across the burner orifice and deriving the gas flow using manufacturer&#39;s burner data and Bernoulli&#39;s equation), then the λ referential  value in Equation 1 or 2 assumed by the manufacturer is utilized. In another example, as shown in  FIG. 18 , if lambda is independent of firing rate and never drifts over time, then the lambda value measured in the field at the combustion appliance serves as λ actual . Referring to  FIG. 19 , if lambda is dependent on firing rate and never shifts, then this dependency is measured during commissioning and λ actual =λ(FR). In yet another example, if the lambda is dependent on firing rate and drifts over time, then the dependency is measured during commissioning and updated during operation of the combustion appliance, and λ actual =λ(FR,t), as shown in  FIG. 20 . Alternatively, if the fuel flow dependency on firing rate can be constructed or measured during commissioning (the fuel flow dependency for a gaseous fuel can be constructed using pressure drop across the burner orifice and deriving the gas flow using manufacturer&#39;s burner data and Bernoulli&#39;s equation), then lambda obtained during commissioning also may be used as λ referential  in Equation 1 or 2. In other words, λ actual =λ referential . In still yet another example, if lambda is dependent on firing rate and drifts over time, the drifted dependency is used for correction as λ actual =λ(FR,t), as shown in  FIG. 22 . 
     For the illustrative examples described above, the sensor of flue gas oxygen may be used to obtain the actual lambda value. In addition, while in the simplest examples gas and air pressure and temperature may be neglected to determine a corrected volume of fuel, sensors for gas pressure and temperature may be utilized to correct for the drift of gas pressure and/or temperature which may adversely affect the accuracy of fuel metering and hence, the determination of fuel consumption. Other factors, such as barometric pressure, altitude, flue gas oxygen concentration, and reference standards may also be factored in to the determination of a corrected fuel consumption determination. 
     Electronic Cycle Counting 
     In operation, gas valve assembly  10  may monitor the number of operational valve cycles experienced by one or more valve sealing member  22  over a period of time (such as the lifetime of gas valve assembly  10 ). In one example, valve controller  26  of valve assembly  10  may monitor a valve sealing member  22  of at least one of the valve ports  20  being opened from a closed position and/or being returned to the closed position to complete an operational cycle, where a plurality of operational cycles may be completed during the lifetime of the valve assembly  10 . In one example, a count of the number of operational cycles may be maintained and/or stored in a non-volatile memory  37 , or other memory, of valve controller  26  (e.g., microcontroller  36  or other device) of valve assembly  10  in a tamper proof manner. Alternatively, and to detect an operation cycle, valve controller  26  of valve assembly  10  may monitor a valve sealing member  22  moving from an open position to a closed position and back to an open position, or any other cycle involving movement of valve sealing member  22  and/or other parts, portions or devices of valve assembly  10 . In some cases, valve controller  26  may monitor valve actuators  30 , positions of valve sealing member  22  and/or signals to valve actuators  30 , and/or other indicators to monitor the number of operational valve cycles experienced by each valve port  20  over a period of time, such as the lifetime of valve assembly  10 . 
     The memory (e.g., non-volatile memory  37 ) of valve controller  26  storing the electronic operational valve cycle counting system may also be programmed with one or more number of cycles for which valve assembly  10  may be rated (e.g., one or more threshold numbers of operational valve cycles). Valve controller  26  may be configured to retrieve the one or more threshold numbers of operational valve cycles from the non-volatile memory  37 , and compare the count of the number of operational valve cycles to the one or more threshold numbers of operational valve cycles. If desired, valve assembly  10  may be configured to take action if a counted number of cycles meets and/or exceeds one of the one or more threshold numbers of valve cycles. Taking action may include, for example, after a first threshold number of operational cycles has been surpassed, initiating a warning or an alarm  78  or sending for a maintenance call, and after a second threshold number of operational cycles has been surpassed, shutting the system down by removing power from main valve switches  72 ,  74 , preventing valve actuator(s)  30  from selectively moving valve sealing member(s)  22  (e.g., preventing the opening of valve port(s)  20 ), and/or any other desired action. 
     As the operational valve cycle data may be electronically stored in memory (e.g., non-volatile memory  37 ) of microcontroller  36 , the valve cycle data (e.g., a total number of operational cycles, etc.) may be communicated and/or outputted to one or more remote devices, such as system controller  50  and/or appliance controller  60 , via a wired or wireless communication interface including or connected to a bus or link  100  or other link, where the operational valve cycle data (e.g., total number of operational cycles, etc.) may be displayed on displays  52 ,  62  or other display interfaces. Alternatively, or in addition, the operational valve cycle data may be displayed on a handheld device and/or a display at or adjacent valve assembly  10  (e.g., a touch-screen on valve body  12 ) or on another display or device, as desired. 
     In addition, microcontroller  36  may be configured to continuously or discontinuously monitor and/or analyze the duration and number of cycles, time between half cycles (time between the open and closing of the valve), and/or other parameters to help determine any abnormal patterns that would be indicative of system or component malfunction and/or failures, and/or other normal or abnormal patterns. In some further illustrative instances, the electronic counter may take the place of an electronic clock on the system, such that the operational cycle count may be utilized as a digital time stamp when storing information on various events detected by valve controller  26 , such as diagnostic, warning and/or error messages and the like. 
     Overpressure Diagnostics 
     Valve assembly  10  may be configured to detect, report, and/or automatically act upon an overpressure event occurrence at, within, and/or on valve assembly  10 . An overpressure event may be an event where pressure at the input port  14 , output port  16 , or within fluid channel  18  of valve assembly  10  is greater than an overpressure threshold value (e.g., a valve pressure rating value, a pressure value below which the specifications of the valve assembly  10  are guaranteed, a pressure value below which it is guaranteed no damage will occur to the valve assembly  10  from pressure, a pressure value between the pressure value below which the specification of valve assembly  10  is guaranteed and the pressure value below which it is guaranteed no damage will occur to the valve assembly  10  from pressure, etc.), where the overpressure may cause damage to the valve assembly  10 . Acting on such sensed overpressure events may, for example, take a valve offline until the valve can be inspected, enable more accurate system diagnostics under some circumstances, optimize maintenance scheduling, minimizing service and down time, and/or increasing safety levels with respect to valve assembly  10 . These are just some examples. 
     The overpressure threshold value may be related to a valve pressure rating value of valve assembly  10  and/or valve ports  20  therein. The overpressure threshold value may be substantially equal to or less than or greater than the valve pressure rating value of valve assembly  10 . A valve pressure rating value may be any pressure value assigned to valve assembly  10 . For example, a valve pressure rating value may be equal to or less than a pressure value at which valve assembly  10  or valve ports  20  within valve assembly  10  is or are expected to fail or become otherwise damaged. 
     Similarly, a pressure sensor  38 ,  42 ,  43 ,  44  of pressure sensor assembly  24 , which may continuously monitor pressure levels of fluid flowing through fluid channel  18 , may have a sensor pressure rating value. In an illustrative instance, the sensor pressure rating value of at least one of the pressure sensors  38 ,  42 ,  43 ,  44  may be equal to or substantially greater than the valve pressure rating of valve assembly  10 . In some cases, there may be multiple overpressure threshold values, which may indicate different levels of severity of an overpressure event, and/or may be useful for other purposes or may indicate different thresholds at different locations along the fluid channel  18  (e.g., at the input and output of fluid channel  18 ) where pressure levels are being sensed and/or monitored. 
     Valve controller  26  of valve assembly  10  may be utilized to facilitate overpressure diagnostics. Valve controller  26 , which may be secured relative to valve body  12  and in communication with pressure sensor assembly  24 , may be configured to compare a measure related to a sensed pressure of fluid (e.g., fuel, etc.) flowing through fluid channel  18  of valve body  12  with an overpressure threshold value stored in non-volatile memory  37  or other memory accessible by valve controller  26 . The sensed pressure may be sensed by pressure sensor assembly  24  at any position along fluid channel or path  18 ; for example, a pressure may be sensed upstream of one or more valve port(s)  20  (e.g., first and/or second valve port  20   a ,  20   b ) or downstream of one or more valve port  20  (e.g., first and/or second valve port  20   a ,  20   b ) or if there are two or more valve ports  20  (e.g., first valve port  20   a  and second valve port  20   b ), then in between, upstream or downstream valve ports  20 . Pressure sensor assembly  24  may be configured to utilize one or more pressure sensors  38 ,  42 ,  43 ,  44  that may facilitate continuously sensing a pressure in fluid channel  18  at one or more desired locations (e.g., upstream of a first valve port  20   a ) and then automatically and repeatedly, or continuously, communicate the sensed pressure at the desired location(s) to valve controller  26 . 
     Valve controller  26  may be configured to determine if the measure related to the sensed pressure exceeds or surpasses the overpressure threshold value. If the measure does surpass the overpressure threshold value, the valve controller  26  may be configured to provide a predetermined output signal indicating that an over pressure event has occurred. The predetermined output signal may be provided to a remote device (e.g.  50  or  60 ) and/or an audible and/or visual alarm may be displayed on a remote display (e.g.,  52 ,  62 ) or a display located adjacent and/or on valve assembly  10 . Alternatively, or in addition, the predetermined output signal may, indirectly or directly, cause valve actuator(s)  30  to close valve port(s)  20  (e.g., by closing valve sealing member(s)  22  therein) and/or cause valve controller  26  to store the over pressure event in a non-volatile memory  37  or other memory of valve controller  26  and/or other device. The predetermined output signal may also, indirectly or directly, cause valve controller  26  to store one or more of a time stamp of the overpressure event, a level of the sensed pressure causing the overpressure event, a duration of the overpressure event, a cumulative number of overpressure events, classification identifier of the overpressure event, any parameter calculated from a series of measured pressure readings, and/or other related or unrelated data. 
     The stored data or information related to the overpressure events may be processed and/or analyzed by valve controller  26  and/or transferred to other devices. Processing the stored information may include, but is not limited to, determining a most likely cause of an over pressure event, classifying the event by most likely cause, estimating the severity of the event, calculating the cumulative number of over pressure events, comparing any of the stored information (e.g., level of the sensed pressure causing the event, time stamp of an event, duration of an event, number of events, severity of an event, etc.), which may be stored in valve controller  26 , to one or more threshold values that may also be stored in valve controller  26  or at one or more other locations, notifying a user by visual or audible means or alarm, running self checking diagnostics to evaluate key performance characteristics (e.g., seat leakage testing through a VPS test, regulator performance etc.), indirectly or directly closing valve port(s)  20  via valve actuator(s)  30 , and/or sending a signal to trigger some system level overpressure countermeasure in response to a measure surpassing a respective threshold value. Additionally, all or some or none of the actions and/or results of the processing may be communicated to users or other devices over communication link  100 , an I/O interface, and/or any other communication mechanism. 
     High Gas Pressure and Low Gas Pressure Detection 
     Valve assembly  10  may be configured to monitor the occurrence of pressure events along a fluid channel  18 . Valve assembly  10  may be configured as an electronic module for detecting low gas pressure (LGP) upstream of first valve port  20   a  and high gas pressure (HGP) downstream of the first valve port  20   a  and/or second valve port  20   b  or another valve port  20  depending on which valve port  20  is the most downstream valve port  20  in valve assembly  10 . By placing a pressure sensor  42  upstream of the first valve port  20  to sense an inlet gas pressure and/or placing a pressure sensor  42  downstream of the second valve port  20  to sense an outlet gas pressure and/or placing a pressure sensor  42  in an intermediate volume  19  between a first valve port  20   a  and a second valve port  20   b  to sense an intermediate volume gas pressure, the electronics of valve assembly  10  may be configured to electronically emulate and/or perform electromechanical or mechanical HGP/LGP switch functions, such that the functions of electromechanical or mechanical HGP/LGP switches may be directly integrated in valve assembly  10 . At a minimum, a single pressure sensor is needed to perform both HGP/LGP switch functions in accordance with this disclosure. The integration of the switch functions may facilitate internalizing wiring connections within valve body  12 , and may result in size and cost savings due, at least in part, to valve and switch functions sharing a common housing, while providing other solutions and benefits as would be generally realized. 
     In an illustrative instance, one or more first pressure sensors  42 , positioned upstream of first valve port  20   a , may continuously or discontinuously sense an inlet pressure in fluid channel  18  and may be in communication with valve controller  26 . Valve controller  26  may be configured to continuously or discontinuously compare a first measure (e.g., inlet pressure) or data related thereto, which may be stored in memory (e.g., non-volatile memory  37 ) of valve controller  26 , that at least tracks a measure related to a sensed pressure sensed by the one or more first pressure sensors  42  in valve body  12  upstream of first valve port  20   a , with a first pressure threshold programmed into and stored in memory (e.g., non-volatile memory  37 ) of valve controller  26 . Valve controller  26  may then provide a predetermined first output signal if the first measure surpasses the first pressure threshold, where the first output signal may result in first valve actuator  30   a  closing first valve port  20   a  and second valve actuator  30   b  closing second valve port  20   b.    
     In an illustrative example, valve controller  26  may compare the first measure to a low gas pressure threshold (e.g., a first pressure threshold) and if the first measure drops below or is less than the low gas pressure threshold, the first measure may be said to have surpassed the low pressure threshold, and valve controller  26  may provide the predetermined first output signal. Alternatively, or in addition, valve controller  26  may be configured to compare the first measure with a second pressure threshold (e.g., a high gas pressure threshold) programmed into and stored in valve controller  26 , where valve controller  26  may be configured to provide a predetermined second output signal if the first measure surpasses the second pressure threshold (e.g., if the first measure is greater than or more than the high pressure threshold). The first and second pressure thresholds may be automatically, manually through a user interface, locally (e.g., on a valve assembly&#39;s  10  own display/user interface  76 ), and/or remotely (e.g., via an appliance or system level display  52 ,  62  and communication bus  100 ) determined and programmed during setup. In some cases, the first and second pressure thresholds may be selectable from the American National Standards Institute (ANSI) standards and/or European (EN) standards. For example, a first or high gas pressure threshold may be 125% of a first pressure run and a second or low gas pressure threshold may be 75% of a first pressure run. The predetermined first and second pressure output signal may indicate a pressure event has occurred and/or other data or information related to the pressure event. 
     Likewise, one or more second pressure sensors  43  positioned downstream of first valve port  20   a  and/or second valve port  20   b  may continuously or discontinuously sense outlet pressures in fluid channel  18  and may be in communication with valve controller  26 . Valve controller  26  may be configured to continuously or discontinuously compare a second measure (e.g., outlet pressure) or data related thereto, which may be stored in memory (e.g., non-volatile memory  37 ) of valve controller  26 , that at least tracks a sensed pressure in valve body  12  downstream of second valve port  20   b  with a third pressure threshold or other pressure threshold programmed into and stored in memory (e.g., non-volatile memory  37 ) of valve controller  26 . Valve controller  26  may then provide a predetermined third output signal if the second measure surpasses the third pressure threshold, where the third output signal may result in first valve actuator  30   a  closing first valve port  20   a  and second valve actuator  30   b  closing second valve port  20   b.    
     In an illustrative example, valve controller  26  may compare the second measure to a high gas pressure threshold and if the second measure rises above the high gas pressure threshold, the second measure may be said to have surpassed the high gas pressure threshold and valve controller  26  may provide the predetermined third output signal. Alternatively, or in addition, valve controller  26  may be configured to compare the second measure with a fourth pressure threshold (e.g., a low pressure threshold), or other pressure threshold, programmed into and stored in valve controller  26 , where valve controller  26  may be configured to provide a predetermined fourth output signal if the second measure surpasses the fourth pressure threshold. The predetermined third and fourth output signals may indicate a pressure event has occurred and/or other data or information related to the pressure event. 
     In a similar manner, one or more third pressure sensors  44  positioned downstream of first valve port  20   a  and upstream of second valve port  20   b  may continuously or discontinuously sense an intermediate pressure, or a measure related thereto, in intermediate volume  19  of fluid channel  18  and may be in communication with valve controller  26 . Valve controller  26  may be configured to continuously or discontinuously compare a third measure (e.g., intermediate pressure) or data related thereto, which may be stored in memory (e.g., non-volatile memory  37 ) of valve controller  26  with a fifth pressure threshold or other pressure threshold programmed into and stored in memory (e.g., non-volatile memory  37 ) of valve controller  26 . Valve controller  26  may then provide a predetermined fifth output signal if the third measure surpasses the fifth pressure threshold, where the fifth output signal may result in first valve actuator  30   a  closing first valve port  20   a  and second valve actuator  30   b  closing second valve port  20   b.    
     In an illustrative example, valve controller  26  may compare the third measure to a high gas pressure threshold and if the third measure rises above the high gas pressure threshold, valve controller  26  may provide the predetermined fifth output signal. Alternatively, or in addition, valve controller  26  may be configured to compare the third measure with a sixth pressure threshold (e.g. a low pressure threshold), or other pressure threshold, programmed into and stored in valve controller  26 , where valve controller  26  may be configured to provide a predetermined sixth output signal if the third measure surpasses the sixth pressure threshold. The predetermined fifth and sixth output signals may indicate a pressure event has occurred and/or other data or information related to the pressure event. 
     As discussed above, the HGP/LGP testing may be performed with one or more pressure sensors. The numbering and positioning of the pressure sensors (e.g., first pressure sensor  42 —upstream, second pressure sensor  43 —downstream, third pressure sensor  44 —intermediate, etc.) is for illustrative purposes only. For example, there may be a single pressure sensor in valve assembly  10 , where the single pressure sensor is located upstream of the valve port(s)  20 , downstream of the valve port(s)  20  or intermediate the valve ports  20 . Further, each pressure sensor  38 ,  42 ,  43 ,  44  included in valve assembly  10  may be associated with one or more pressure threshold value and those one or more pressure threshold values may be similar to or different from one or more pressure threshold values associated with any other pressure sensor. 
     Valve controller  26  may include software to effect methods of operation disclosed herein. In some illustrative instances, software filtering techniques may be utilized to eliminate transient pressure readings from causing a false opening of a switch  69  in the limit string  67 , for example, a switch in series with safety switch  70 , which may help prevent nuisance valve port(s)  20  closures. Safety switch  70  may be wired in series between main valve switches  72 ,  74  and the limit string  67 , for example. In such a configuration, if valve controller  26  detects a pressure event, valve controller  26  may initiate a series of actions resulting in a switch  69  in the limit string  67  opening, which may remove power from main valve switches  72 ,  74 , resulting in valve ports  20  closing. The software may help improve robustness of the system by allowing the software to be intelligent about when it monitors the sensor states and what action is taken in response. 
     As the functions of HGP/LGP switches may now be emulated by sensors and electronics, and the output may no longer only be a simple “switch open” or “switch closed”, but rather, in addition or alternatively, an actual readable pressure value or value related thereto, it may be advantageous to configure valve controller  26  to communicate this data to a remote device (e.g., a building automation system or system controller  50 , an appliance controller  60 , etc.) or display  52 ,  62 . System display  52  or appliance display  62  may be configured to show threshold pressures along with actual sensed pressures during operation to show a user how much margin there is until a pressure event trip point. In addition, valve controller  26  may be configured to communicate to system controller  50  or appliance controller  60  that a pressure event has occurred, which may result in an indicator being displayed on displays  52 ,  62 . Such communication may take place over a wired or wireless bus or link  100 , where the bus may be configured to carry data to and from valve assembly  10 . In some cases, low and high pressure thresholds may be inputted by an operator of valve assembly  10  and may be downloaded or otherwise programmed into valve controller  26 . 
     Note, first, second, third, fourth, fifth and sixth pressure thresholds and output signals are merely some illustrative examples, and there may be any number of pressure thresholds and output signals with respect to each provided pressure sensor  42 ,  43 ,  44  (or  38 ), as desired. Further, with respect to a first and second pressure threshold related to a single valve port  20  and/or pressure sensor  42 ,  43 ,  44  (or  38 ), one of the first or second pressure threshold may relate to a high or low pressure threshold and the other pressure threshold may relate to the other of the high and low pressure thresholds. In addition, each of the one or more first pressure sensors  42 , each of the one or more second pressure sensors  43  and each of the third pressure sensors  44 , respectively, may include pressure sensors each having different or the same pressure sub-ranges. For example, where two third pressure sensors  44  are positioned downstream of the first valve port  20   a  and upstream of second valve port  20   b , one of the two third pressure sensors  44  may have a first pressure sensing sub-range over which it may sense pressures and the other of the two third pressure sensors  44  may have a second pressure sensing sub-range over which it may sense pressures, but this is not required. 
     Although valve controller  26  may be configured to provide the above-mentioned first, second, third, fourth, fifth, and/or sixth output signals when the first, second, or third sensed measure related to each valve port  20  surpasses one of the pressure threshold stored in valve controller  26  to indicate a pressure event has occurred, valve controller  26  may be configured to not provide the predetermined first, second, third, fourth, fifth, or sixth output signal during at least one time period, even if any of the first, second, or third measures surpass a respective pressure threshold. For example, valve controller  26  may be programmed to not provide the predetermined output signal where the one time period is associated with a status of the first and/or second valve actuators  30   a ,  30   b  (e.g., at or around when the first and/or second valve actuator  30   a ,  30   b  are being actuated, etc.). Actuating the first and/or second valve actuator  30   a,    30   b  may cause pressure transients, which could result in false HGP or LGP events. In some, but not all cases, for example, microcontroller  36  may be taught to ignore sensed pressures when valve port(s)  20  is/are closed, as the outlet pressure may be close to zero and likely below any threshold value and a sensed pressure in the intermediate volume  19  may be in a range from around zero to the inlet pressure. 
     Although typical safety valve assemblies may have sensed HGP downstream of a second valve port  20   b  and LGP upstream of a first valve port  20   a , utilizing sensors of pressure sensor assembly  24  may allow pressure to be monitored at a single pressure sensor positioned at a single location (e.g. upstream of the first valve, intermediate the first and second valves, or downstream of the second valve) in or about valve assembly  10 . Further, the microcontroller  36  onboard the valve assembly  10  may allow the valve controller  26  to assess when the combustion appliance is on and when it is off and in which state (e.g. open/closed) the valve sealing members  22  are positioned. Furthermore, it is possible to observe with one or more pressure sensors both HGP and LGP states upstream, downstream, and/or intermediate valve port(s)  20 . As discussed, a single pressure sensor may be located at any position within or about valve assembly  10 , such that the pressure sensor may be in fluid communication with fluid channel  18 . A single pressure sensor configuration for detecting HGP and LGP may be facilitated by having microprocessor  36  observing sensed data for both low and high pressure conditions simultaneously. In one example, a single pressure sensor intermediate the first valve port  20   a  and the second valve port  20   b , may monitor for both HGP and LGP events in the gas stream provided to the gas valve assembly  10 . In the example, the single pressure sensor intermediate the first valve port  20   a  and the second valve port  20   b  may monitor for both HGP and LGP events whenever at least the first valve port  20   a  is open. 
     Valve Proving System Test 
     Valve controller  26  may be configured to perform an electronic valve proving system (VPS) test on valve assembly  10 , where all or substantially all of the structure required for the VPS may be integrated directly into valve assembly  10 . When so provided, the direct integration may allow sensors and electronics needed for VPS testing to share a common housing. Valve assembly  10  may be in communication with combustion appliance controller  60  or other device, and may at least partially control a fuel flow to a combustion appliance through fluid channel  18 . Illustratively, the combustion appliance may cycle on and off during a sequence of operational cycles, where at least some of the operational cycles may include performing a VPS test prior to and/or after igniting received fuel during the corresponding operational cycle. For example, VPS tests may be performed on each valve port  20  prior to igniting received fuel during a corresponding operational cycle, VPS tests may be performed on each valve port  20  after a call for heat is satisfied (e.g., at the very end of an operational cycle), or a VPS test may be performed on a first valve port  20  prior to igniting received fuel during a corresponding operational cycle and on a second valve port  20  after a call for heat is satisfied. Due to the timing of the VPS test before and/or after operational cycles, or both, the test may be achieved in an amount of time consistent with the useful operation of an individual appliance (e.g., a short amount of time of 10-15 seconds or 5-30 seconds or a longer amount of time) depending on the inlet pressure, size of the intermediate volume  19 , volume of the appliance combustion chamber, length of time of the appliance pre-purge cycle, firing rate of the appliance burner, the leakage threshold level, etc. The VPS test may be an automated process that occurs every, or at least some, operational cycle(s) (e.g., once the VPS test has been set up by a field installer or at the original equipment manufacturer, the testing may not require the end user to participate in any way). 
     The structural set up of valve assembly  10  for a VPS test may include valve controller  26  in communication with a pressure sensor  44  that may be in fluid communication with intermediate volume  19  between two valve ports (e.g., first valve port  20   a  and second valve port  20   b , as seen in  FIG. 8 ). Where valve controller  26  is in communication with pressure sensor  44 , valve controller  26  may be configured to determine a measure related to a pressure change rate (e.g., pressure rise or pressure decay rate, or other measure) in intermediate volume  19  during each VPS test performed as part of at least some of the operational cycles of the combustion appliance, or at other times. Alternatively, or in addition, valve controller  26  may be in communication with one or more inlet pressure sensor  42 , outlet pressure sensor  43  or other pressure sensors (e.g., differential pressure sensor  38  and/or other sensors), where pressure sensors  38 ,  42 ,  43  sense measures related to the pressure upstream of a first port  20   a  and downstream of a second port  20   b , respectively, and communicate the sensed measures to valve controller  26 . Although pressure sensors downstream of the ports (e.g., pressure sensor(s)  43 ) may not be directly used to determine whether a valve is leaking, the downstream pressure sensor(s)  43  may continuously monitor outlet pressure during leakage tests of the valves and, in some cases, may facilitate determining which valve is leaking if a valve leakage is detected. 
     In some cases, utilizing an inlet pressure sensor  42  in addition to or as an alternative to pressure sensor  44  may allow controller  26  to determine in real time which valve port  20  is leaking. By using pressure sensor  42  at the inlet, the inlet pressure may be known prior to a VPS sequence and controller  26  may be able to pre-determine thresholds for pressure rise and decay based on knowing the inlet pressure prior to the VPS sequence. Such pre-determination of the thresholds may allow sensed pressures to be compared to the thresholds at any time during the VPS sequence. 
     Valve controller  26  may include non-volatile memory  37  or other memory that may include a first VPS threshold value (e.g., for comparing to a pressure rise) and a second VPS threshold value (e.g., for comparing to a pressure decay) utilized in performing the VPS test. Alternatively, or in addition, the memory may be located at a position other than in valve controller  26 , such that any remote memory may be in communication with valve controller  26 . Valve controller  26  may further be configured to compare the determined measure related to a pressure change rate in the intermediate volume  19  to the first and/or second threshold value during a first valve leakage test having a first duration, and/or comparing the measure that is related to a pressure change rate in the intermediate volume  19  to the third and/or fourth threshold value during a second valve leakage test having a second duration that is longer than the first duration. Illustratively, the first and/or second threshold values may be utilized in a valve leakage test each time a combustion appliance or other device connected to valve assembly  10  opens one or more valve ports  20 , for example, in a VPS test or other test. The third and/or fourth threshold values may be utilized in a valve leakage test or other test performed as scheduled maintenance while valve assembly  10  is offline, at the time of commissioning of valve assembly  10 , and/or at other preferred times. 
     The VPS test may be achieved by commanding valve actuators  30  to open and/or closed in a useful sequence. This sequence may be initialized and/or controlled through valve controller  26  and/or through the combustion appliance controller  60 . When the VPS sequence is initialized and controlled remotely (e.g., remote from valve controller  26 ) through the combustion appliance controller  60 , the valve controller  26  may be configured to detect if the VPS test or another test is occurring by monitoring gas valve assembly  10  and signals communicated to valve assembly  10 . If the VPS test is to be controlled by the valve controller  26 , the set up of the VPS settings may occur at a display/user interface  76  on board the valve itself or at a remote display (e.g., displays  52 ,  62 ). If the VPS test is to be actuated or initiated at or through combustion appliance controller  60 , the set up of the VPS settings may occur at a remote display (e.g., displays  52 ,  62 ). Valve controller  26  may monitor valve actuators  30   a ,  30   b , first control signal (MV 1 ) controlling first valve actuator  30   a  and second control signal (MV 2 ) controlling second valve actuator  30   b , and/or the states of valve ports  20   a ,  20   b  (e.g., by monitoring the output of position sensor(s)  48 ) to identify if the VPS test is occurring. First and second control signals (MV 1  and MV 2 ) may be actuated by a combustion appliance controller  60  in communication with valve assembly  10  or by a valve controller  26  or by a field tool in communication with valve controller  26  or any other tool or individual in communication with valve assembly  10 . Although the field tool and other tools are most often used for actuating first and second control signals (MV 1  and MV 2 ) in a valve leakage test, such similar or different tools may be used to operate a VPS test or for system level diagnostics and/or troubleshooting by a trained appliance technician in the field. 
     In performing a VPS test, valve controller  26  may cause or identify the following first predetermined sequence. The first valve actuator  30   a  may close the first valve port  20   a  (if not already closed). The second valve actuator  30   b  may then open the second valve port  20   b  (if not already opened) to depressurize the intermediate volume  19  between the first valve port  20   a  and the second valve port  20   b . The second valve actuator  30   b  may then close the second valve port  20   b  to seal the depressurized intermediate volume  19 . 
     Valve controller  26  may cause or identify this first predetermined sequence as a first sub-test of a VPS test, and valve controller  26  may be configured to compare a measure that is related to the pressure change rate in intermediate volume  19  to a first VPS sub-test threshold value prior to, during, or after a first sub-set VPS duration. After or while comparing the measure related to the pressure change rate in intermediate volume  19  to the first sub-test threshold value, valve controller  26  may output a signal if the measure meets and/or exceeds the first sub-test threshold value. Valve controller  26  may be configured to output the signal over the communication bus  100  or using a simple pair of contacts (e.g., relay contacts that close when a measured pressure surpasses a threshold pressure value) at or in communication with appliance controller  60 , one or more of a local display, a remote device  50 ,  60  and/or a remote display  52 ,  62  of the remote device(s)  50 ,  60 . The first sub-test of the VPS test may be configured to at least detect a leaking first valve port  20   a . The outputted signal may indicate, or may cause to be indicated, a valve leakage within valve assembly  10  and/or a measure of the magnitude of the valve leakage. 
     In addition to identifying the first sub-test of a VPS test, valve controller  26  may cause or identify the following second predetermined sequence. The second valve actuator  30   b  may close the second valve port  20   b  (if not already closed). The first valve actuator  30   a  may then open the first valve port  20   a  (if not already opened) to pressurize the intermediate volume  19  between the first valve port  20   a  and the second valve port  20   b . The first valve actuator  30   a  may then close the first valve port  20   a  to seal the pressurized intermediate volume  19 . 
     Valve controller  26  may cause or identify this second predetermined sequence as a second sub-test of a VPS test, and valve controller  26  may be configured to compare a measure that is related to the pressure change rate in intermediate volume  19  to a second VPS sub-test threshold value prior to, during, or after a second sub-set VPS duration. After or while comparing the measure related to the pressure change rate in intermediate volume  19  to the second sub-test threshold value, valve controller  26  may output a signal if the measure meets and/or exceeds the second sub-test threshold value. Valve controller  26  may be configured to output the signal to one or more of a local display, a remote device  50 ,  60  and/or a remote display  52 ,  62  of the remote device(s)  50 ,  60 . The second sub-test of the VPS test may be configured to at least detect a leaking second valve port  20   b . The outputted signal may indicate, or may cause to be indicated, a valve leakage within valve assembly  10  and/or a measure of the magnitude of the valve leakage. Further, first VPS sub-test and second VPS sub-test of the VPS test may be performed in any order, as desired. 
     The first and second VPS sub-test threshold values may be programmed into valve controller  26 , and the first and second VPS sub-test threshold values may be different or substantially the same value. Alternatively, or in addition, valve controller  26  may be configured to calculate the first and second VPS sub-test threshold values based on one or more parameters and, in some instances, the valve controller  26  may be configured to store the first and second VPS sub-test threshold values. The one or more parameters that valve controller  26  may consider if it is determining a VPS sub-test threshold value include, but are not limited to, a sensed pressure, a sensed temperature, max flow rate of the system, a number of ON-OFF cycles operated up to a point in time, volume of flow channel  18 , altitude of valve assembly  10 , barometric pressure, absolute pressure, gas type (e.g., density), ANSI requirements, EN requirements, other agency requirements, an allowed VPS test duration, and how small of a leak is to be detected, etc. Further, in the event more than two sub-tests are performed as part of the VPS test, there may be more threshold values than the first and second VPS sub-test threshold values, if desired. 
     In an illustrative operation, a VPS test may be performed on a valve assembly  10  that is coupled to a non-switched gas source, or other gas source, that is under a positive pressure during the VPS test to test gas valve assembly  10  for leaks. 
     A similar VPS test performed on valve assembly  10  may include opening one of the first and second valve port  20   a ,  20   b  with the other of the first and second valve ports  20   a ,  20   b  remaining or being closed. After opening one of the first and second valve ports  20   a ,  20   b,  closing the opened valve port such that both valve ports  20   a ,  20   b  are closed such that a first initial gas pressure may be present in intermediate volume  19 . An intermediate pressure sensor  44  may continuously or discontinuously sense a pressure in intermediate volume  19 , including the first initial pressure therein, and send the sensed pressures to valve controller  26 . The initial pressure in intermediate volume  19  may be sensed at any time, for example, the initial pressure may be sensed after opening one of the valve ports  20   a ,  20   b  and before closing that opened valve port  20   a ,  20   b . Valve controller  26  may monitor (e.g., continuously or discontinuously), over time, the pressure in intermediate volume  19  and determine a first measure that is related to a pressure change rate within intermediate volume  19  while both valve ports  20   a ,  20   b  are in a closed position. After determining the first measure that is related to a pressure change rate within intermediate volume  19 , valve controller  26  may compare the determined first measure related to a pressure change rate in the intermediate volume  19  to a first threshold value stored in valve controller  26 . Valve controller  26  may then output to a display and/or remote device  50 ,  60  or other device an output signal that is related to the first measure related to the pressure change rate (e.g., a determined pressure change in intermediate volume  19 , or other determined measure), where outputting the output signal may also include storing the determined first measure related to the pressure change rate in non-volatile memory  37  on valve controller  26 . Optionally, valve controller  26  may output the output signal if the determined first measure meets and/or exceeds the first threshold value. The output signal, however, may convey any information, as desired. For example, the output signal may convey information related to when (e.g. time stamp) the determined measure that is related to the pressure change rate meets and/or exceeds a threshold value, or other information related to or not related to the pressure in intermediate volume  19 . In an alternative, or in addition to providing the output signal, a visual and/or audible indicator may be provided to indicate if valve assembly  10  passed or failed the VPS test. 
     In addition, first and/or second valve port  20   a ,  20   b  may be manipulated such that a second initial gas pressure may be present in the intermediate volume  19  while the first and second valve ports  20   a ,  20   b  are in the closed position. For example, second valve port  20   b  may be closed, then the first valve port  20   a  may be opened to pressurize intermediate volume  19  and then closed to seal in the second initial pressure. The second initial pressure may be substantially different than the first initial gas pressure, as the first initial pressure may be associated with a depressurized state of intermediate volume  19  and the second initial pressure may be associated with a pressurized state of intermediate volume  19 , for example. Similar to above, intermediate pressure sensor  44  may sense pressure within intermediate volume  19  and communicate the sensed pressure and measures related to the sensed pressures to valve controller  26 . Valve controller  26  may monitor (e.g., continuously or discontinuously), over time, the pressure in intermediate volume  19  and determine a second measure that is related to a pressure change rate within intermediate volume  19  while both valve ports  20   a ,  20   b  are in the closed position. After determining the second measure that is related to a pressure change rate within intermediate volume  19 , valve controller  26  may compare the determined second measure related to a pressure change rate in the intermediate volume  19  to a second threshold value stored in valve controller  26 . Valve controller  26  may then output to a display and/or remote device  50 ,  60  or other device an output signal that is related to the second measure related to a pressure change rate, where outputting the output signal may also include storing the determined second measure related to the pressure change rate in non-volatile memory  37  on valve controller  26 . Optionally, valve controller  26  may output the output signal or a different output signal if the determined second measure meets and/or exceeds the second threshold value. The output signal, however, may convey any information and the outputted signals may be outputted in any situation. Further, the output signal may be configured to provide, or cause to be provided, a visual and/or audible indicator to indicate if valve assembly  10  passed and/or failed the VPS test. 
     The steps of the illustrative VPS test may be performed once such as when the gas valve assembly  10  is installed or during routine maintenance, and/or the steps may be repeated during each combustion cycle of a combustion appliance. In either case, the valve controller  26  or other device, or even a user, may identify a trend in the stored determined measures related to the pressure change rate or in other data sensed, calculated and/or stored during the valve leakage tests. A determined trend may be used for any of many purposes, for example, a trend may be used to predict when the valve will require replacement and/or servicing, and/or to make other predictions. Further, a VPS test and/or leakage test may be initiated and/or operated dependent on or independent of an attached device (e.g., a combustion appliance controller  60 ). In such an instance, valve controller  26  may be configured to initiate and operate a VPS test and/or leakage test independent of an attached device and may be configured to disable a heat call or other signal to and/or from an attached device, when appropriate. 
     Valve Leakage Test (VLT) 
     Valve controller  26  may be configured to perform a Valve Leakage (VL) Test on valve assembly  10 . Valve controller  26  may be manually initialized by a field service technician or other user at either a local display on the valve assembly  10  (e.g., when valve controller  26  controls the operation of the VL test) or at a remote display  52 ,  62  (e.g., when either the valve controller  26  controls the operation of the VL test or when the VL test is remotely controlled). Similar to the set up for a VPS test, the structural set up of valve assembly  10  for a VL test may include valve controller  26  in communication with a pressure sensor  44  that may be in fluid communication with intermediate volume  19  between two valve ports  20  (e.g., first valve port  20   a  and second valve port  20   b ), as seen in  FIG. 8 . Where valve controller  26  is in communication with pressure sensor  44 , valve controller  26  may be configured to determine a measure related to a pressure change rate (e.g., pressure rise or decay rate, or other measure) in intermediate volume  19  when both the first valve port  20   a  and second valve port  20   b  are closed. 
     The VL test may be performed in the same manner as the VPS test discussed above. However, in the VL test, the test duration may be longer (e.g., one minute, two minutes, several minutes, or other time period that may possibly be longer than a typical length of time it may take to run a VPS test) during which time a combustion appliance may be offline, thereby allowing smaller leaks to be detected. Also, the thresholds values used during the VL test may be different from those used in the VPS test. Also, the VL test may be performed less frequently than the VPS test. For example, the VL test may be performed once a year or during routine maintenance, and not during every combustion cycle. 
     In some cases, valve controller  26  may be configured to initiate a VL test. In some instances, the valve controller  26  may be configured to detect if a VPS test or a longer, Valve Leakage (VL) test, is occurring by monitoring gas valve assembly  10  and signals communicated to valve assembly  10 . For example, valve controller  26  may monitor valve actuators  30   a ,  30   b,  first control signal (MV 1 ) controlling first valve actuator  30   a  and/or second control signal (MV 2 ) controlling second valve actuator  30   b , and/or the states of valve ports  20   a ,  20   b  to identify if a VPS test or a longer VL test is occurring. In some cases, first and second control signals (MV 1  and MV 2 ) may be controlled by a combustions appliance in communication with valve assembly  10  or a field tool in communication with valve assembly  10  or any other tool or individual in communication with valve assembly  10 . If a VL test is detected, valve controller  26  may automatically apply thresholds associated with the longer VL test rather than thresholds of the shorter VPS test. The valve controller  26  may revert back, automatically or otherwise, to using VPS thresholds after the longer VL test has been completed, if desired. 
     When valve assembly  10  may be disconnected from a combustion appliance controller  60  and connected to a field tool to effect the VL test with VL thresholds, it is contemplated that when combustion appliance controller  60  is reconnected with valve assembly  10 , previous combustion appliance-valve assembly thresholds/conditions (e.g., VPS thresholds) may be automatically reset, as valve controller  26  and device controller  60  may automatically detect the reconnection. 
     Having thus described several illustrative embodiments of the present disclosure, those of skill in the art will readily appreciate that yet other embodiments may be made and used within the scope of the claims hereto attached. Numerous advantages of the disclosure covered by this document have been set forth in the foregoing description. It will be understood, however, that this disclosure is, in many respect, only illustrative. Changes may be made in details, particularly in matters of shape, size, and arrangement of parts without exceeding the scope of the disclosure. The disclosure&#39;s scope is, of course, defined in the language in which the appended claims are expressed.