Abstract:
The disclosure provides an HVAC data processing and communication network. In various embodiments of systems and methods including a bus, a compressor is coupled to the bus, and a subnet controller is coupled to the bus. The subnet controller disables the compressor when acting upon a dehumidification command.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application Ser. No. 61/167,135, filed by Grohman, et al., on Apr. 6, 2009, entitled “Comprehensive HVAC Control System”, and is a continuation-in-part application of application Ser. No. 12/258,659, filed by Grohman on Oct. 27, 2008, entitled “Apparatus and Method for Controlling an Environmental Conditioning Unit,” both of which are commonly assigned with this application and incorporated herein by reference. This application is also related to the following U.S. patent applications, which are filed on even date herewith, commonly assigned with this application and incorporated herein by reference: 
         [0000]    
       
         
               
               
               
             
           
               
                   
               
               
                 Serial No. 
                 Inventors 
                 Title 
               
               
                   
               
             
             
               
                 [Attorney 
                 Grohman, 
                 “Alarm and Diagnostics System and Method 
               
               
                 Docket No. 
                 et al. 
                 for a Distributed-Architecture Heating, 
               
               
                 080161] 
                   
                 Ventilation and Air Conditioning 
               
               
                   
                   
                 Network” 
               
               
                 [Attorney 
                 Wallaert, 
                 “Flush Wall Mount Control Unit and In- 
               
               
                 Docket No. 
                 et al. 
                 Set Mounting Plate for a Heating, 
               
               
                 070064] 
                   
                 Ventilation and Air Conditioning System” 
               
               
                 [Attorney 
                 Thorson, 
                 “System and Method of Use for a User 
               
               
                 Docket No. 
                 et al. 
                 Interface Dashboard of a Heating, 
               
               
                 070027] 
                   
                 Ventilation and Air Conditioning 
               
               
                   
                   
                 Network” 
               
               
                 [Attorney 
                 Grohman 
                 “Device Abstraction System and Method 
               
               
                 Docket No. 
                   
                 for a Distributed-Architecture Heating, 
               
               
                 070016] 
                   
                 Ventilation and Air Conditioning 
               
               
                   
                   
                 Network” 
               
               
                 [Attorney 
                 Grohman, 
                 “Communication Protocol System and 
               
               
                 Docket No. 
                 et al. 
                 Method for a Distributed-Architecture 
               
               
                 070079] 
                   
                 Heating, Ventilation and Air 
               
               
                   
                   
                 Conditioning Network” 
               
               
                 [Attorney 
                 Hadzidedic 
                 “Memory Recovery Scheme and Data 
               
               
                 Docket No. 
                   
                 Structure in a Heating, Ventilation and 
               
               
                 080151] 
                   
                 Air Conditioning Network” 
               
               
                 [Attorney 
                 Grohman 
                 “System Recovery in a Heating, 
               
               
                 Docket No. 
                   
                 Ventilation and Air Conditioning 
               
               
                 080173] 
                   
                 Network” 
               
               
                 [Attorney 
                 Grohman, 
                 “System and Method for Zoning a 
               
               
                 Docket No. 
                 et al. 
                 Distributed-Architecture Heating, 
               
               
                 080131] 
                   
                 Ventilation and Air Conditioning 
               
               
                   
                   
                 Network” 
               
               
                 [Attorney 
                 Grohman, 
                 “Method of Controlling Equipment in a 
               
               
                 Docket No. 
                 et al. 
                 Heating, Ventilation and Air 
               
               
                 080163] 
                   
                 Conditioning Network” 
               
               
                 [Attorney 
                 Grohman, 
                 “Programming and Configuration in a 
               
               
                 Docket No. 
                 et al. 
                 Heating, Ventilation and Air 
               
               
                 080160] 
                   
                 Conditioning Network” 
               
               
                   
               
             
          
         
       
     
     
    
     TECHNICAL FIELD 
       [0002]    This application is directed, in general, to distributed-architecture heating, ventilation and air conditioning (HVAC) system, more specifically, to general control techniques in an HVAC network. 
       BACKGROUND 
       [0003]    Climate control systems, also referred to as HVAC systems (the two terms will be used herein interchangeably), are employed to regulate the temperature, humidity and air quality of premises, such as a residence, office, store, warehouse, vehicle, trailer, or commercial or entertainment venue. The most basic climate control systems either move air (typically by means of an air handler or, or more colloquially, a fan or blower), heat air (typically by means of a furnace) or cool air (typically by means of a compressor-driven refrigerant loop). A thermostat is typically included in the climate control systems to provide some level of automatic temperature control. In its simplest form, a thermostat turns the climate control system on or off as a function of a detected temperature. In a more complex form, a thermostat may take other factors, such as humidity or time, into consideration. Still, however, the operation of a thermostat remains turning the climate control system on or off in an attempt to maintain the temperature of the premises as close as possible to a desired setpoint temperature. Climate control systems as described above have been in wide use since the middle of the twentieth century. 
       SUMMARY 
       [0004]    A first aspect provides a bus, a compressor coupled to the bus, and a subnet controller coupled to the bus. In an embodiment, the subnet controller disables the compressor when acting upon a dehumidification command. 
         [0005]    A second aspect provides a method for employing an HVAC network. In an embodiment, the method includes receiving a dehumidification command; and disabling a compressor coupled to the HVAC network when acting upon the dehumidification command. 
         [0006]    A third aspect provides an HVAC network. In an embodiment, the network includes a bus, a compressor coupled to the bus, and a subnet controller coupled to the bus. The subnet controller disables the compressor when acting upon a dehumidification command, and wherein the dehumidification command is received by the subnet controller over an Internet. 
     
    
     
       BRIEF DESCRIPTION 
         [0007]    Reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which: 
           [0008]      FIG. 1  is a high-level block diagram of an HVAC system within which a device abstraction system and method may be contained or carried out; 
           [0009]      FIG. 2  is a high-level block diagram of one embodiment of an HVAC data processing and communication network  200 ; 
           [0010]      FIG. 3A  is a diagram of a series of steps in an event sequence that depicts a device commissioning in an HVAC network having an active subnet controller; 
           [0011]      FIG. 3B  is a diagram of a series of steps that occur in relation to a setting up of a subnet including an addressable unit; 
           [0012]      FIG. 3C  is a diagram of the above series of steps of  FIG. 3B  to be followed by a subnet controller to synchronize with a device of the HVAC system; 
           [0013]      FIG. 4  is an illustration of an exemplary flow method of an ability to display weather information and forecast future HVAC network functionality; 
           [0014]      FIGS. 4A and 4B  are an illustration of a heating and cooling scenario employing the exemplary weather prediction flow of  FIG. 4 ; 
           [0015]      FIG. 5A  is an illustration of one embodiment of RFID system for use with a remote comfort sensor in an HVAC network; and 
           [0016]      FIG. 5B  is an illustration of an exemplary flow method of employment of an RFID with a remote comfort sensor; 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    As stated above, conventional climate control systems have been in wide use since the middle of the twentieth century and have, to date, generally provided adequate temperature management. However, it has been realized that more sophisticated control and data acquisition and processing techniques may be developed and employed to improve the installation, operation and maintenance of climate control systems. 
         [0018]    Described herein are various embodiments of an improved climate control, or HVAC, system in which at least multiple components thereof communicate with one another via a data bus. The communication allows identity, capability, status and operational data to be shared among the components. In some embodiments, the communication also allows commands to be given. As a result, the climate control system may be more flexible in terms of the number of different premises in which it may be installed, may be easier for an installer to install and configure, may be easier for a user to operate, may provide superior temperature and/or relative humidity (RH) control, may be more energy efficient, may be easier to diagnose and perhaps able to repair itself, may require fewer, simpler repairs and may have a longer service life. 
         [0019]      FIG. 1  is a high-level block diagram of an HVAC system, generally designated  100 . The HVAC system may be referred to herein simply as “system  100 ” for brevity. In one embodiment, the system  100  is configured to provide ventilation and therefore includes one or more air handlers  110 . In an alternative embodiment, the ventilation includes one or more dampers  115  to control air flow through air ducts (not shown.) Such control may be used in various embodiments in which the system  100  is a zoned system. In the context of a zoned system  100 , the one or more dampers  115  may be referred to as zone controllers  115 . In an alternative embodiment, the system  100  is configured to provide heating and therefore includes one or more furnaces  120 , typically associated with the one or more air handlers  110 . In an alternative embodiment, the system  100  is configured to provide cooling and therefore includes one or more refrigerant evaporator coils  130 , typically associated with the one or more air handlers  110 . Such embodiment of the system  100  also includes one or more compressors  140  and associated condenser coils  142 , which are typically associated in one or more so-called “outdoor units”  144 . The one or more compressors  140  and associated condenser coils  142  are typically connected to an associated evaporator coil  130  by a refrigerant line  146 . In an alternative embodiment, the system  100  is configured to provide ventilation, heating and cooling, in which case the one or more air handlers  110 , furnaces  120  and evaporator coils  130  are associated with one or more “indoor units”  148 , e.g., basement or attic units. 
         [0020]    For convenience in the following discussion, a demand unit  155  is representative of the various units exemplified by the air handler  110 , furnace  120 , and compressor  140 , and more generally includes an HVAC component that provides a service in response to control by the control unit  150 . The service may be, e.g., heating, cooling, or air circulation. The demand unit  155  may provide more than one service, and if so, one service may be a primary service, and another service may be an ancillary service. For example, for a cooling unit that also circulates air, the primary service may be cooling, and the ancillary service may be air circulation (e.g. by a blower). 
         [0021]    The demand unit  155  may have a maximum service capacity associated therewith. For example, the furnace  120  may have a maximum heat output (often expressed in terms of British Thermal Units, or BTU), or a blower may have a maximum airflow capacity (often expressed in terms of cubic feet per minute, or CFM). In some cases, the addressable unit  155  may be configured to provide a primary or ancillary service in staged portions. For example, blower may have two or more motor speeds, with a CFM value associated with each motor speed. 
         [0022]    One or more control units  150  control one or more of the one or more air handlers  110 , the one or more furnaces  120  and/or the one or more compressors  140  to regulate the temperature of the premises, at least approximately. In various embodiments to be described, the one or more displays  170  provide additional functions such as operational, diagnostic and status message display and an attractive, visual interface that allows an installer, user or repairman to perform actions with respect to the system  100  more intuitively. Herein, the term “operator” will be used to refer collectively to any of the installer, the user and the repairman unless clarity is served by greater specificity. 
         [0023]    One or more separate comfort sensors  160  may be associated with the one or more control units  150  and may also optionally be associated with one or more displays  170 . The one or more comfort sensors  160  provide environmental data, e.g. temperature and/or humidity, to the one or more control units  150 . An individual comfort sensor  160  may be physically located within a same enclosure or housing as the control unit  150 . In such cases, the commonly housed comfort sensor  160  may be addressed independently. However, the one or more comfort sensors  160  may be located separately and physically remote from the one or more control units  150 . Also, an individual control unit  150  may be physically located within a same enclosure or housing as a display  170 . In such embodiments, the commonly housed control unit  150  and display  170  may each be addressed independently. However, one or more of the displays  170  may be located within the system  100  separately from and/or physically remote to the control units  150 . The one or more displays  170  may include a screen such as a liquid crystal display (not shown). 
         [0024]    Although not shown in  FIG. 1 , the HVAC system  100  may include one or more heat pumps in lieu of or in addition to the one or more furnaces  120 , and one or more compressors  140 . One or more humidifiers or dehumidifiers may be employed to increase or decrease humidity. One or more dampers may be used to modulate air flow through ducts (not shown). Air cleaners and lights may be used to reduce air pollution. Air quality sensors may be used to determine overall air quality. 
         [0025]    Finally, a data bus  180 , which in the illustrated embodiment is a serial bus, couples the one or more air handlers  110 , the one or more furnaces  120 , the one or more evaporator coils  130 , the one or more condenser coils  142  and compressors  140 , the one or more control units  150 , the one or more remote comfort sensors  160  and the one or more displays  170  such that data may be communicated therebetween or thereamong. As will be understood, the data bus  180  may be advantageously employed to convey one or more alarm messages or one or more diagnostic messages. 
         [0026]      FIG. 2  is a high-level block diagram of one embodiment of an HVAC data processing and communication network  200  that may be employed in the HVAC system  100  of  FIG. 1 . One or more air handler controllers (“AHCs”)  210  may be associated with the one or more air handlers  110  of  FIG. 1 . One or more integrated furnace controllers (“IFCs”)  220  may be associated with the one or more furnaces  120 . One or more damper controller modules  215 , also referred to as a zone controller module  215 , may be associated with the one or more dampers  114  the interface the one or more dampers to the data bus  180 . One or more AC controllers  225  may be associated with one or more evaporator coils  130  and one or more condenser coils  142  and compressors  140  of  FIG. 1 . The network  200  includes an active subnet controller (“aSC”)  230   a  and an inactive subnet controller (“iSC”)  230   i . The aSC  230   a  is responsible for configuring and monitoring the system  100  and for implementation of heating, cooling, air quality, ventilation or any other functional algorithms therein. Two or more aSCs  230   a  may also be employed to divide the network  200  into subnetworks, or subnets, simplifying network configuration, communication and control. The iSC  230   i  is a subnet controller that does not actively control the network  200 . In some embodiments, the iSC  230   i  listens to all messages passed over the data bus  180 , and updates its internal memory to match that of the aSC  230   a . In this manner, the iSC  230   i  may backup parameters stored by the aSC  230   a , and may be used as an active subnet controller if the aSC  230   a  malfunctions. Typically there is only one aSC  230   a  in a subnet, but there may be multiple iSCs therein, or no iSC at all. Herein, where the distinction between an active or a passive SC is not germane the subnet controller is referred to generally as an SC  230 . 
         [0027]    A user interface (UI)  240  provides a means by which an operator may communicate with the remainder of the network  200 . In an alternative embodiment, a user interface/gateway (UI/G)  250  provides a means by which a remote operator or remote equipment may communicate with the remainder of the network  200 . Such a remote operator or equipment is referred to generally as a remote entity. A comfort sensor interface  260  may provide an interface between the data bus  180  and each of the one or more comfort sensors  160 . 
         [0028]    Each of the components  210 ,  220 ,  225 ,  230   a ,  230   i ,  240 ,  250 ,  260  may include a general interface device configured to interface to the bus  180 , as described below. (For ease of description any of the networked components, e.g., the components  210 ,  220 ,  225 ,  230   a ,  230   i ,  240 ,  250 ,  260 , may be referred to generally herein as a device  290 . In other words, the device  290  of  FIG. 2  is a proxy for any of a furnace, a heat pump, a subnet controller, etc, and that device&#39;s associated interface means.) The data bus  180  in some embodiments is implemented using the Bosch CAN (Controller Area Network) specification, revision 2, and may be synonymously referred to herein as a residential serial bus (RSBus)  180 . The data bus  180  provides communication between or among the aforementioned elements of the network  200 . It should be understood that the use of the term “residential” is nonlimiting; the network  200  may be employed in any premises whatsoever, fixed or mobile. In wireless embodiments, the data bus  180  may be implemented, e.g., using Bluetooth™ or a similar wireless standard. 
         [0029]    In the illustrated embodiment, a user interface (“UI”)  240  provides a means by which a person may communicate with the remainder of the network  200 . In an alternative embodiment, a user interface/gateway (“UI/G”)  250  provides an approach by which a remote person or remote equipment may communicate with the remainder of the network  200 . Such a remoter person or equipment is referred to generally as a remote entity. Components connected to the data bus  180  may be referred to in the following description generally as a bus interface  260 , also referred to herein simply as an “interface  260 .” The interface  260  may provide network interface functions to any of the aforementioned HVAC system components, e.g., the air handler  110 , furnace  120 , coils  130  or compressor  150  over the data bus  180 . The data bus  180 , which may be referred to hereinafter as a residential serial bus, or RSBus, provides communication between or among the aforementioned elements of the network  200 . It should be understood that the use of the term “residential” is nonlimiting; the network  200  may be employed in any premises whatsoever, personal or business, fixed or mobile. 
         [0030]    Generally, the network  200  allows for the remote comfort sensors  160 , the controller  150 , and user display  165  and/or remote user displays  170  to operate independently as separate logical units, and can be located in separate locations within the network  200 . This is unlike the prior art, wherein these functionalities were required to be located within a single physical and logical structure. 
         [0031]    Turning now to  FIG. 3A , illustrated is a diagram  300  of a series of steps that occur in relation to a commissioning of the unit  155  in the illustrated embodiment. The diagram  300  includes an enter state  301 , a device commissioning state  303 , and an exit state  305 . The HVAC system  100  can be described as being partitioned into a plurality of subnets, each subnet controlled by its own active subnet controller  230   a.    
         [0032]    Device commissioning can generally be defined as setting operational parameters for a device in the network of the HVAC system, including its installation parameters. Generally, device commissioning  300  is used by the subnet controller  230  when it is active to: a) set operating “Installer Parameters” for a networked device, such as air handlers  110 , (henceforth to be referred to collectively, for the sake of convenience, as the unit  155 , although other devices are also contemplated), b) to load UI/Gs  240 ,  250  with names and settings of “Installer Parameters and Features” of the units  155 , c) to configure replacement parts for the units  155 , and d) to restore values of “Installer Parameters and Features” in units  155  if those “Parameters and Features” were lost due to memory corruption or any other event. Device commissioning is a process used in the HVAC system  100 , either in a “configuration” mode or in a “verification” mode. 
         [0033]    In the illustrated embodiment and in the “configuration” mode, the unit  155  shares its information with the subnet controller  230   a  in an anticipation of being employable in the HVAC system  100 , and an appropriate subnet. Generally, the commissioning process  300  provides a convenient way to change or restore functional parameters, both for the subnet controller  230   a  and the unit  155 . 
         [0034]    In both the “verification” mode and the “configuration” mode, the unit  155  is checked for memory errors or other configuration or programming errors. There are differences in device  290  behavior between the “configuration” mode and in the “verification” mode, to be detailed below. 
         [0035]    The “subnet startup” mode programs the subnet controller  230  to be active. The “subnet startup” mode enables subnet communications, (i.e., communication within a subnet), and also deactivates a “link” sub-mode. A “link” mode may be generally defined as a mode that allows a number of subnets to work together on the same HVAC network  200 , and that assigns subnet numbers for each subnet to allow this communication. 
         [0036]    The “installer test” mode is employed when an installer installs and tests aspects and units of the HVAC system  100 . The “normal operations” mode is an ongoing operation of devices  290  of the HVAC system  100  in a normal use. 
         [0037]    More specifically, the device commissioning state machine  300  can be employed in: a) the “configuration” mode, which is invoked when transitioning to the commissioning state from the “subnet startup mode” or “installer test” mode, or the “normal mode,” or b) a “verification” mode. In the illustrated embodiment, the “verification” mode is invoked when transitioning to the commissioning state from the “subnet startup” mode. 
         [0038]    The following describes an illustrative embodiment of a process of commissioning  300  the HVAC unit  155 , first for a “configuration” mode, and then for a “verification” mode. The process of commissioning differs from a “subnet startup,” in that commissioning requires that the network configuration, including configuration and activation of subnet controllers  230 , has already been completed before the commissioning  300  of the device  260  can start. In the illustrated embodiment, there can be more than one subnet controller  230  on a subnet, but only subnet controller  230   a  is active at any one time. 
         [0039]    In one embodiment, in order to enter into the state  320  of the process  300  in the “configuration” mode, the unit  155  receives either: a) an “aSC” (&#39;active subnet controller&#39;) Device Assignment message,” having “Assigned State” bits set to “Commissioning”; or b) a receipt of an “aSC Change State” message, with “New aSC State” bits set to “Commissioning,” from the active subnet controller  230 . For both “configuration” and “verification” modes, an “aSC Device Assignment” message can be generally regarded as a message that assigns the unit  155  to a particular active subnet controller  230   a . For both “configuration” and “verification” modes, an “aSC Change State” message can be generally regarded as a message that starts and ends employment of the commissioning state diagram  300  for the units  155  and all other devices on the subnet. 
         [0040]    In the illustrated embodiment and in the state  320  in the configuration mode, all units  155  respond to the “aSC Device Assignment” message with their respective “Device Status” messages, indicating that the units  155  are now in commissioning process  300  due to their response to this previous message. For both “configuration” and “verification” modes, the “Device Status” message can be generally defined as message that informs the active subnet controller  230   a  of what actions are being taken by the unit  155  at a given time. 
         [0041]    However, alternatively, in other embodiments, in the state  320  in the “configuration” mode, if the units  155  are instead busy, as indicated by “aSC Acknowledge” bits of the “Device Status” message sent to the subnet controller  230   a  set as a “Control Busy,” the active subnet controller  230   a  will wait for the busy units  155  to clear their “aSC Acknowledge” bits before proceeding with further elements of the Commissioning  320  process. The units  155  then resend their “Device Status” messages as soon as they are no longer busy. 
         [0042]    From this point on, all units  155  send their “Device Status” messages periodically and on any status change, both during and after the commissioning  300 . If the unit  155  does not clear its “aSC Acknowledge” bits within a minute (indication its control is no longer “busy”), the active subnet controller  230   a  sends an “Unresponsive Device2” alarm for each such unit  155 . If in “configuration” mode, the active subnet controller  230   a  remains in the waiting mode indefinitely, until the unit  155  responds correctly, or the subnet is reset manually or after a timeout is reached. In “verification” mode the active subnet controller  230   a  proceeds further to exit the state. 
         [0043]    In the illustrated embodiment and in the “configuration” mode, each unit  155  remembers all of its optional sensors that are currently attached to it. Furthermore, each unit  155  may store a local copy in its non-volatile memory (“NVM”) of all of any other unit features that it is dependent on. A unit  155  feature can be generally defined as any datum that is fixed and cannot be changed by the installer, serviceman or the home owner. Changing of a “Feature” value normally involves reprogramming of the units  155  firmware. 
         [0044]    In at least some embodiments, a feature is something that is fixed value, that is hard-wired into a device. In other words, no installer or home owner can change it. Features are programmed into the unit  155  during a manufacturing or an assembly process. Features can be recovered in a home, during a Data non-volatile memory (“NVM”) recovery substate of Commissioning state only—the recovery substate happens automatically and without installer or user intervention. In a further embodiment, parameters can be changed by the installers only. In a yet further embodiment, the HVAC system  100  employs “variables”—those can be changed by the installers and also the home owners. 
         [0045]    In some embodiments, a “Parameter List” is normally a Feature that contains a special list of specific parameters included in the unit  155 . Parameter values can be changed, and their state can be changed also (from enabled to disabled and vice-versa), but their presence is set once and for all in a given firmware version. Therefore, a list of Parameters (not their values) is also fixed, and is thus treated as a “Feature.” 
         [0046]    However, although elements of the “configuration” mode commissioning and “verification” mode commissioning are similar, when the active subnet controller  230  is in “verification” mode instead of in “configuration” mode, the active subnet controller  230   a  can exit commissioning  300  regardless of the value of the alarms of the units  155 . However, alternatively, if the active subnet controller  230   a  is in “configuration” mode, the active subnet controller  230   a  will not exit from its commissioning state  300  for as long as at least one unit&#39;s  155  “aSC Acknowledge” flags are set to “Control Busy.” In one embodiment of the “verification” mode, the active subnet controller  230   a  timeouts the installation and resets the subnet to default parameters. 
         [0047]    In the “verification” mode, assuming the unit  155  operates with a non-corrupted (original or restored copy) NVM, each unit  155  checks any of its attached sensors to see if they match with the parameters that were present in a most recent configuration of the unit  155 . In some embodiments, alarms are generated by the unit  155  for missing or malfunctioning sensors as soon as the faulty condition is detected, to be employed by the user interfaces and gateways present on the subnet to notify the installer or homeowner of the encountered problem. The unexpected absence of certain sensors may inhibit the operation of the unit  155  or the subnet. This is normally manifested by the signaling of the appropriate Service Bits in the Device Status message used by the active subnet controller  230   a , to determine the operational viability or health of the subnet&#39;s systems. 
         [0048]    In some embodiments, the device commissioning process  300  then transitions into a state  330 , and then ends, upon either: a) the last unit  155  receiving all of unit  155  parameters that it is dependent on, when in “verification” mode; or b) upon a request by a user, when in “configuration” mode. The active subnet controller  230   a  then proceeds to ensure that no subnet unit  155  has its “aSC Acknowledge” flag set to a “Control Busy” state. The “aSC Acknowledge” flag not being set indicates that all of a non-volatile memory of a given unit  155  had been written to with the necessary parameters. If no “Control Busy” state is detected, the active subnet controller  230   a  then issues the “aSC Change State” message, which forces the unit  155  from a commissioning state to a non-commissioning state, in either a “configuration” or a “verification” mode. 
         [0049]    In some embodiments, when the unit  155  in the process  300  fails its NVM data integrity check in an “NVM CRC Check,” and the active subnet controller is unable to perform NVM Recovery, the unit  155  instead employs its default data stored in its non-volatile (Flash) memory and/or uses default calculations to initialize the data dependent on other devices in the system. The other device data to be used for commissioning could have been obtained in either the “verification” or “configuration” mode. For data or other parameters that were not transferred or generated as part of that commissioning  300  session, default values are used. 
         [0050]    In one embodiment, upon a detection of a system configuration error, such as a missing device whose features or parameters the unit  155  depends upon, it uses the locally stored copy of the other device&#39;s features that it depends upon, and ignores any potential feature value conflicts. In another embodiment, the unit  155  uses the locally stored copy of other parameters of the unit  155  that it depends on and ignores any potential dependent parameter value conflicts. In other words, the unit  155  employs a first installed parameter as a template for a second installed parameter on a second device. In a third embodiment, the unit  155  will change its parameter or feature values only if explicitly instructed by the active subnet controller  230  or the UI/G  240 ,  250 . 
         [0051]    Turning now to  FIG. 3B , illustrated is an HVAC device state machine  310  illustrated for a subnet, including the unit  155 , in more detail. Solid lines indicate normal state transitions when the subnet is transitioning from one state to another state, green lines indicate a subroutine call and red lines, alternating dotted and dashed lines indicate unexpected yet valid transitions. All states other than state  326  represent device states, and the state  326  represents a message handling routine. 
         [0052]    As is illustrated in the present embodiment, a reset state  312  of a subnet advances to a NVM CRC check  316  for a given device (such as unit  155 ). If the device fails the test, the device advances to a NVM programming  318 . If the device passes, however, then in subnet startup  320 , the device is assigned an address (Equipment Type number) and some features and parameters of the unit  155  may be shared with the subnet. Then, in substate  324 , device commissioning as described in  FIG. 3A  occurs. This then leads to an installer test state  328 . This, in turn, then leads to a link mode startup  330 , as described above. Finally, then in a step  334 , normal system operation occurs, although system can reset to state  312  or be brought to states  314  or  332  via diagnostic messages handled in a state  326 . 
         [0053]    In a further embodiment, during the NVM CRC check  316 , the state machine  310  can advance to a NVM programming state  318 . This can occur due to such factors as a failure of a non-volatile memory, or an initial programming of the NVM. In a yet further embodiment, each of these units  155  is programmed to deal with one form of a diagnostic message regarding system errors in a state  326 , and from there to testing the device  160  itself in an OEM test mode  332 . 
         [0054]    Turning now to  FIG. 3C , illustrated is a state flow diagram  340  for the active subnet controller  230   a  in relation to the unit  155 . In the illustrated embodiment, it is generally the responsibility of the active subnet controller  230   a  to implement proper state transitions; the other units  155  follow the explicit direction of the aSC  230   a  for all valid transactions. These state diagrams are included to help ensure that a state of the unit  155  is the same as the subnet controller. In the illustrated embodiment, the SC  230   a  is responsible for device synchronization. If the unit  155  is detected out of synch with the rest of the system, the aSC  230   a , in some embodiments, immediately tries to bring the unit  155  to the current system state, if possible. 
         [0055]    If an addressable unit  155  is detected in subnet startup  344 , the subnet controller  230   a  applies asynchronous startup rules, which generally pertain to how many parameters are to be passed between device  290  of the addressable unit  155  and the active subnet controller  230   a.    
         [0056]    If an addressable unit  155  is detected in commissioning  345 , installer test  346 , link mode  347  or normal operation  348  substates, the unit  155 , in some embodiments, is brought to the current state via a resend of an “aSC Change State” message, which involves transitioning from a first current aSC state to a second current aSC state. 
         [0057]    If a unit  155  is detected in OEM Test or Soft Disabled state, the unit  155  shall be reset by the active subnet controller  230   a  in a step  342 . If a unit  155  is detected in “Hard Disabled” or “NVM Programming” state, the active subnet controller  230   a  assumes that it is not available on the subnet. 
         [0058]    In a further embodiment, inactive subnet controllers  230   i  are required to keep the most up to date subnet and HVAC system configuration information. Inactive subnet controllers  230   i  listen to all UI/G and aSC messages and continuously update their non-volatile memory to attempt to be as consistent as possible with the settings stored in active subnet controller  230   a.    
       Various Aspects of General Control Techniques in an HVAC Network 
       [0059]    Turning now to  FIG. 4 , illustrated is an exemplary method  400  for using weather information as to when to provide HVAC networked services. Prior art HVAC systems generally only use indoor temperature to make decisions on when to bring on HVAC equipment to provide conditioning to a space. Prior art HVAC systems do not predict whether outdoor conditions will change, that could affect the decision of HVAC functions. 
         [0060]    In the illustrated embodiment, the method  400  gathers both current weather information and forecasted information. The current weather information and forecasted weather information can be displayed on the display(s)  170 . This provides a homeowner or other user convenient access to this weather information, without a need to watch for this information on television, the World Wide Web, or newspaper. 
         [0061]    In a further embodiment, the method  400  can use the forecasted weather information to make decisions on when to engage and disengage different functionalities of the HVAC network  200 . For example, the indoor temperature may indicate that there is a need to bring on cooling. However, the weather forecast may indicate that the outside temperature will drop within the next few hours, and the residence will cool off due to natural cooling. Thus, the method  400  may defer the call for cooling, and instead rely on the outside temperature to drop the temperature of the residence naturally, thus saving the user money. An analogous situation applies to the furnace and heating of the residence due to a predicted warming. In some embodiments, the weather forecast can be input to the communicating system via Internet, cell phone network, phone network, cable network, satellite, or other forms of wired radio frequency communications. In another embodiment, the communication form can be wireless Internet or other forms of wireless communication. 
         [0062]    In the method  400 , after a start step  405 , an HVAC network (such as the HVAC network  200 ) may gather current weather information in a step  410 . This current weather information is displayed to a user in a step  420 . In a step  430 , the HVAC network gathers forecasted weather information. In a step  440 , the HVAC network makes present HVAC control decisions based upon the forecasted weather information. In one embodiment, the forecasted weather information can be conveyed to the HVAC system via the U/IG  250 , which can be coupled to the Internet. In another embodiment, home information to be considered by the method  400  when making present HVAC decisions is also entered in the step  440  by the user or installer. Please note that this information can be entered into the active subnet controller  230   a  either during commissioning or normal operation. 
         [0063]    Generally, the method  400  allows for controlling of the HVAC system  100  to improve system performance, e.g. comfort and efficiency for a consumer. In one embodiment of the method  400 , all equipment control is based on both current and forecasted temperature. Start time can depend on a present indoor temperature, outdoor temperature and overall weather forecast. 
         [0064]    For an example of employment of the method  400 , electricity prices may vary by time of day, with electric rates being less expensive before 2 pm and more expensive from 2 pm to 5 pm. If the weather forecast indicates that it will be hot in the afternoon, the method  500  may decided to “pre-cool” the space in the morning and rely on the thermal storage of the home to keep it cool in the afternoon. In this manner, the homeowner can shift their cooling energy usage to a time when electric rates are less expensive, thus saving the homeowner money. 
         [0065]    In a further embodiment of  FIG. 2  as expressed in conjunction with  FIGS. 3A-3C , if the active network controller  230   a  generates or receives a ‘dehumidify’ command, the compressor  140  is disabled during a dehumidify command, thus avoiding overcooling in a given space. In some embodiments, this can be correlated to the weather prediction functionality. 
         [0066]    Turning now to  FIG. 4A , illustrated is both a prior art and current control technique according to method  400  for heating. As is illustrated in  FIG. 4A , a required indoor temperature  460  is illustrated in relation to an outdoor temperature  465 . In conventional systems, a furnace would turn on at a point  470 , a turn-on point of outside temperature. This would overshoot a desired indoor temperature  460 . However, the method  400  allows a turn on time instead at an earlier time based on a weather prediction such as in the step  440 , thereby allowing the indoor temperature to reach its target temperature at a desired time. 
         [0067]    Turning now to  FIG. 4B , illustrated is both a prior art and current control technique according to method  400  for cooling. As is illustrated in  FIG. 4B , a required indoor temperature  480  is illustrated in relation to an outdoor temperature  485 . In conventional systems, a compressor and fan would turn on at a point  490 , which could require significant energy. However, the method  400  allows the cooling to be turned on at a later time  495  based on a weather prediction by using a natural coolness of the environment itself such as in the step  440 , thereby allowing the indoor temperature to reach its target temperature at a desired time. 
         [0068]    Turning now to  FIG. 5A , illustrated is a system  500  for employing radio frequency identification (“RFID”) with temperature and/or humidity sensors, such as the comfort sensors  280 . An RFID may not need batteries to power a microprocessor. Instead, an RFID tag may use an antenna to draw power from a transmitted radio signal as well as derive information from it. A basic principle behind the latter type of RFID is when a proper frequency is transmitted, and an RFID tag draws enough power to radiate an ID or other signal, transmits its ID or another signal to a receiver and then presumably turns back off. All of this can happen without a use of batteries. 
         [0069]    In the system  500 , illustrated is a sensor  505 , which can be the comfort sensor  280 , although it may or may not have additional humidity sensing ability. The sensor  500  includes an RFID tag  510 , a thermistor  220 , and a battery  530 . The system  500  also includes an RFID transceiver  540 , coupled to the RS bus  180  of the HVAC network  200 . 
         [0070]    Generally, the system  500  incorporates an RFID into a remote temperature sensor, such as the sensor  505 . The temp sensor includes both the RFID tag  510 , which reads the thermistor  520 . Therefore, the temperature sensors may not be powered all of the time, but perhaps only when the RFID receiver  540  powers up at the request of the HVAC network  200 . Therefore, when the sensors  505  are powered by an RF signal, an interrogatory signal, they then read the thermistor  520 , broadcast this value, and then go back to “sleep.” In a further embodiment, the RF temperature sensor  505  can be incorporated with the battery  530  that only powers the thermistor so that the sensor can put all of its power received from the RFID receiver  540  into transmitting data. In a yet further embodiment, a plurality of sensors  500  are placed around a location, such as a room. The temperature sensors each have a separate broadcast frequency. In one embodiment, the sensor is motionless and thus able to receive power longer, with less loss and better reliability, so it can include low-power active circuitry whose sole purpose is to convert the ADC reading of the thermistor value into an RF message packet. 
         [0071]    Turning now to  FIG. 5B , illustrated is an exemplary embodiment of a method  550  for reading a value, such as a temperature, in an RFID, such as the RFID tag  510 , that has a value to be employed by an HVAC network, such as the HVAC network  200 . After a start step  555 , an RFID receiver of a HVAC network sends an interrogatory signal to an RFID tag in a sensor in a step  560 , such as the RFID tag  510  in the sensor  505 . In a step  570 , the RFID tag recognizes the RFID interrogatory signal. In a step  580 , the RFID tag reads an internal sensor, such as the thermistor, for a value. In a step  590 , the RFID tag broadcasts the thermistor value using the energy of the interrogatory signal. In a step  595 , the RFID receiver of the HVAC network receives the thermistor value broadcast from the RFID. The method stops in a step  597 . 
         [0072]    Those skilled in the art to which this application relates will appreciate that other and further additions, deletions, substitutions and modifications may be made to the described embodiments.