Patent Publication Number: US-2022214653-A1

Title: Building management system with point virtualization for online meters

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 16/052,083, filed Aug. 1, 2018, which claims the benefit of and priority to Indian Provisional Patent Application No. 201741040781, filed Nov. 15, 2017, both of which are incorporated by reference herein in their entireties. 
    
    
     BACKGROUND 
     The present disclosure relates generally to a building management system (BMS) and more particularly to a BMS with point virtualization for online meters. A BMS is, in general, a system of devices configured to control, monitor, and manage equipment in or around a building or building area. A BMS can include, for example, a HVAC system, a security system, a lighting system, a fire alerting system, any other system that is capable of managing building functions or devices, or any combination thereof. 
     A BMS typically monitors multiple facilities and/or buildings within a portfolio using meters that provide live or real-time data samples to the BMS relating to conditions of the building and/or building equipment that serves the building. Each meter may provide one or more points corresponding to physical parameters (e.g., voltage, current, temperature, demand, consumption) to the BMS. The BMS relies on meters to provide data samples of the points, and uses the data to generate metrics, key performance indictors (KPIs), graphical representations of building equipment operation, etc. to deliver to customers. High-end meters may be compatible with BMS networks (e.g., BACnet, Internet Protocol) and may provide multiple points via a single meter, but may be cost prohibitive for many potential BMS customers. Lower-cost or already-installed metering infrastructure generally includes meters which provide only one or two points. The low-cost meters may not provide enough points to make use of many BMS analytics and features. An alternative to adding new, physical meters is simulating virtual points within the BMS. 
     SUMMARY 
     One implementation of the present disclosure is a building management system. The building management system includes a meter configured to provide data samples of a real point. The real point corresponds to a first physical parameter measured by the meter. The building management system also includes an analytics circuit configured to store a real point object representing the real point and store a meter object representing the meter. The meter object includes a points attribute that lists one or more point objects associated with the meter object including at least the real point object. The analytics circuit is also configured to store a virtual point object representing a virtual point. The virtual point corresponds to a second physical parameter not measured by the meter. The analytics circuit is also configured to update the points attribute in the meter object to list the virtual point object as one of the point objects associated with the meter object, receive a data sample of the real point from the meter, calculate a value of the virtual point, and calculate a metric based on the data sample of the real point and the value of the virtual point. The building management system also includes a system manager configured to control building equipment using the metric to affect the first physical parameter and the second physical parameter. 
     In some embodiments, the analytics circuit is configured to calculate the value of the virtual point using a formula stored in the virtual point object. In some embodiments, the analytics circuit is configured to calculate the value of the virtual point using a formula stored in the virtual point object. In some embodiments, the formula defines the value of the virtual point as a function of the data sample of the real point. In some embodiments, the first physical parameter and the second physical parameter characterize operation of the building equipment. 
     In some embodiments, the analytics circuit is further configured to generate a graphical user interface that includes a graphical representation of the operation of the building equipment. The graphical representation is generated based on the data sample of the real point and the value of the virtual point. In some embodiments, the graphical user interface comprises a first indicator identifying the real point as real and a second indicator identifying the virtual point as virtual. 
     Another implementation of the present disclosure is a method for managing a building. The method includes collecting, by a meter, data samples of a real point. The real point corresponds to a first physical parameter measured by the meter. The method includes storing a real point object representing the real point and storing a meter object representing the meter. The meter object includes a points attribute that lists one or more point objects associated with the meter object including at least the real point object. The method includes storing a virtual point object representing a virtual point. The virtual point corresponds to a second physical parameter not measured by the meter. The method includes updating the points attribute in the meter object to list the virtual point object in as one of the point objects associated with the meter object, receiving a data sample of the real point from the meter, calculating a value of the virtual point, calculating a metric based on the data sample of the real point and the value of the virtual point, and controlling, based on the metric, building equipment to affect the first physical parameter and the second physical parameter. 
     In some embodiments, calculating the value of the virtual point includes storing a formula in the virtual point object and calculating the value using the formula. In some embodiments, the method includes generating a graphical user interface that allows the user to input the formula. In some embodiments, the formula defines the value of the virtual point as a function of the data sample for the real point. In some embodiments, the first physical parameter and the second physical parameter characterize operation of the building equipment. 
     In some embodiments, the method includes generating a graphical user interface that includes a graphical representation of the operation of the building equipment based on the data sample of the real point and the value of the virtual point. In some embodiments, the method includes providing, on the graphical user interface, a first indicator identifying the real point as real and a second indicator identifying the virtual point as virtual. 
     Another implementation of the present disclosure is a building management system. The building management system includes building equipment operable to affect a variable state or condition of a building, a plurality of meters configured to collect data samples of a plurality of real points relating to an operation of the building equipment, and an analytics circuit configured to generate a graphical user interface. The graphical user interface includes a points tree widget comprising a list of the plurality of real points, a meter distribution tree widget comprising a list of the plurality of meters, and a meter details widget configured to allow a user to add a virtual point to the list of real points. The analytics circuit is also configured to receive data samples of the plurality of real points, calculate a value of the virtual point, and calculate a metric based on the data samples of the plurality of real points and the value of the virtual point. The building management system also includes a system manager configured to control the building equipment based on the metric. 
     In some embodiments, the graphical user interface includes a virtual point definition widget configured to allow a user to input a formula that defines the virtual point. In some embodiments, the analytics circuit is configured to generate the value of the virtual point using the formula and a first data sample of a first real point of the plurality of real points. In some embodiments, the analytics circuit is configured to generate a graphical representation of an operation of the building equipment using the formula and the data samples of the plurality of real points. 
     In some embodiments, the virtual point definition widget comprises a formula field and a list of the plurality of real points. Each real point on the list of real points is selectable to add the real point to the formula field. The virtual point definition widget also includes a plurality of operator buttons. Each operator button is selectable to add an operator to the formula field. The formula includes one or more real points and one or more operators to define the virtual point as a function of the one or more real points. In some embodiments, the analytics circuit is configured to check the formula input by the user for syntax errors. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a drawing of a building equipped with a HVAC system, according to some embodiments. 
         FIG. 2  is a block diagram of a waterside system which can be used to serve the building of  FIG. 1 , according to some embodiments. 
         FIG. 3  is a block diagram of an airside system which can be used to serve the building of  FIG. 1 , according to some embodiments. 
         FIG. 4  is a block diagram of a building management system (BMS) which can be used to monitor and control the building of  FIG. 1 , according to some embodiments. 
         FIG. 5  is a block diagram of another BMS which can be used to monitor and control the building of  FIG. 1 , according to some embodiments. 
         FIG. 6  is a block diagram of a BMS with a point virtualization circuit  608 , according to some embodiments. 
         FIG. 7  is a block diagram of an object database  606  which can be used in the BMSs of  FIGS. 4-5 , according to some embodiments. 
         FIG. 8  is a flowchart of a process for point virtualization under online meters, according to some embodiments. 
         FIG. 9  is a depiction of a meter configuration interface which can be generated by the BMS of  FIG. 6 , according to some embodiments. 
         FIG. 10  is a depiction of virtual point definition widget which can be generated by the BMS of  FIG. 6 , according to some embodiments. 
         FIG. 11  is a depiction of a building scorecard dashboard which can be generated by the BMS of  FIG. 6 , according to some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     Building HVAC Systems and Building Management Systems 
     Referring now to  FIGS. 1-5 , several building management systems (BMS) and HVAC systems in which the systems and methods of the present disclosure can be implemented are shown, according to some embodiments. In brief overview,  FIG. 1  shows a building  10  equipped with a HVAC system  100 .  FIG. 2  is a block diagram of a waterside system  200  which can be used to serve building  10 .  FIG. 3  is a block diagram of an airside system  300  which can be used to serve building  10 .  FIG. 4  is a block diagram of a BMS which can be used to monitor and control building  10 .  FIG. 5  is a block diagram of another BMS which can be used to monitor and control building  10 . 
     Building and HVAC System 
     Referring particularly to  FIG. 1 , a perspective view of a building  10  is shown. Building  10  is served by a BMS. A BMS is, in general, a system of devices configured to control, monitor, and manage equipment in or around a building or building area. A BMS can include, for example, a HVAC system, a security system, a lighting system, a fire alerting system, any other system that is capable of managing building functions or devices, or any combination thereof. 
     The BMS that serves building  10  includes a HVAC system  100 . HVAC system  100  can include a plurality of HVAC devices (e.g., heaters, chillers, air handling units, pumps, fans, thermal energy storage, etc.) configured to provide heating, cooling, ventilation, or other services for building  10 . For example, HVAC system  100  is shown to include a waterside system  120  and an airside system  130 . Waterside system  120  may provide a heated or chilled fluid to an air handling unit of airside system  130 . Airside system  130  may use the heated or chilled fluid to heat or cool an airflow provided to building  10 . An exemplary waterside system and airside system which can be used in HVAC system  100  are described in greater detail with reference to  FIGS. 2-3 . 
     HVAC system  100  is shown to include a chiller  102 , a boiler  104 , and a rooftop air handling unit (AHU)  106 . Waterside system  120  may use boiler  104  and chiller  102  to heat or cool a working fluid (e.g., water, glycol, etc.) and may circulate the working fluid to AHU  106 . In various embodiments, the HVAC devices of waterside system  120  can be located in or around building  10  (as shown in  FIG. 1 ) or at an offsite location such as a central plant (e.g., a chiller plant, a steam plant, a heat plant, etc.). The working fluid can be heated in boiler  104  or cooled in chiller  102 , depending on whether heating or cooling is required in building  10 . Boiler  104  may add heat to the circulated fluid, for example, by burning a combustible material (e.g., natural gas) or using an electric heating element. Chiller  102  may place the circulated fluid in a heat exchange relationship with another fluid (e.g., a refrigerant) in a heat exchanger (e.g., an evaporator) to absorb heat from the circulated fluid. The working fluid from chiller  102  and/or boiler  104  can be transported to AHU  106  via piping  108 . 
     AHU  106  may place the working fluid in a heat exchange relationship with an airflow passing through AHU  106  (e.g., via one or more stages of cooling coils and/or heating coils). The airflow can be, for example, outside air, return air from within building  10 , or a combination of both. AHU  106  may transfer heat between the airflow and the working fluid to provide heating or cooling for the airflow. For example, AHU  106  can include one or more fans or blowers configured to pass the airflow over or through a heat exchanger containing the working fluid. The working fluid may then return to chiller  102  or boiler  104  via piping  110 . 
     Airside system  130  may deliver the airflow supplied by AHU  106  (i.e., the supply airflow) to building  10  via air supply ducts  112  and may provide return air from building  10  to AHU  106  via air return ducts  114 . In some embodiments, airside system  130  includes multiple variable air volume (VAV) units  116 . For example, airside system  130  is shown to include a separate VAV unit  116  on each floor or zone of building  10 . VAV units  116  can include dampers or other flow control elements that can be operated to control an amount of the supply airflow provided to individual zones of building  10 . In other embodiments, airside system  130  delivers the supply airflow into one or more zones of building  10  (e.g., via supply ducts  112 ) without using intermediate VAV units  116  or other flow control elements. AHU  106  can include various sensors (e.g., temperature sensors, pressure sensors, etc.) configured to measure attributes of the supply airflow. AHU  106  may receive input from sensors located within AHU  106  and/or within the building zone and may adjust the flow rate, temperature, or other attributes of the supply airflow through AHU  106  to achieve setpoint conditions for the building zone. 
     Waterside System 
     Referring now to  FIG. 2 , a block diagram of a waterside system  200  is shown, according to some embodiments. In various embodiments, waterside system  200  may supplement or replace waterside system  120  in HVAC system  100  or can be implemented separate from HVAC system  100 . When implemented in HVAC system  100 , waterside system  200  can include a subset of the HVAC devices in HVAC system  100  (e.g., boiler  104 , chiller  102 , pumps, valves, etc.) and may operate to supply a heated or chilled fluid to AHU  106 . The HVAC devices of waterside system  200  can be located within building  10  (e.g., as components of waterside system  120 ) or at an offsite location such as a central plant. 
     In  FIG. 2 , waterside system  200  is shown as a central plant having a plurality of subplants  202 - 212 . Subplants  202 - 212  are shown to include a heater subplant  202 , a heat recovery chiller subplant  204 , a chiller subplant  206 , a cooling tower subplant  208 , a hot thermal energy storage (TES) subplant  210 , and a cold thermal energy storage (TES) subplant  212 . Subplants  202 - 212  consume resources (e.g., water, natural gas, electricity, etc.) from utilities to serve thermal energy loads (e.g., hot water, cold water, heating, cooling, etc.) of a building or campus. For example, heater subplant  202  can be configured to heat water in a hot water loop  214  that circulates the hot water between heater subplant  202  and building  10 . Chiller subplant  206  can be configured to chill water in a cold water loop  216  that circulates the cold water between chiller subplant  206  building  10 . Heat recovery chiller subplant  204  can be configured to transfer heat from cold water loop  216  to hot water loop  214  to provide additional heating for the hot water and additional cooling for the cold water. Condenser water loop  218  may absorb heat from the cold water in chiller subplant  206  and reject the absorbed heat in cooling tower subplant  208  or transfer the absorbed heat to hot water loop  214 . Hot TES subplant  210  and cold TES subplant  212  may store hot and cold thermal energy, respectively, for subsequent use. 
     Hot water loop  214  and cold water loop  216  may deliver the heated and/or chilled water to air handlers located on the rooftop of building  10  (e.g., AHU  106 ) or to individual floors or zones of building  10  (e.g., VAV units  116 ). The air handlers push air past heat exchangers (e.g., heating coils or cooling coils) through which the water flows to provide heating or cooling for the air. The heated or cooled air can be delivered to individual zones of building  10  to serve thermal energy loads of building  10 . The water then returns to subplants  202 - 212  to receive further heating or cooling. 
     Although subplants  202 - 212  are shown and described as heating and cooling water for circulation to a building, it is understood that any other type of working fluid (e.g., glycol, CO2, etc.) can be used in place of or in addition to water to serve thermal energy loads. In other embodiments, subplants  202 - 212  may provide heating and/or cooling directly to the building or campus without requiring an intermediate heat transfer fluid. These and other variations to waterside system  200  are within the teachings of the present disclosure. 
     Each of subplants  202 - 212  can include a variety of equipment configured to facilitate the functions of the subplant. For example, heater subplant  202  is shown to include a plurality of heating elements  220  (e.g., boilers, electric heaters, etc.) configured to add heat to the hot water in hot water loop  214 . Heater subplant  202  is also shown to include several pumps  222  and  224  configured to circulate the hot water in hot water loop  214  and to control the flow rate of the hot water through individual heating elements  220 . Chiller subplant  206  is shown to include a plurality of chillers  232  configured to remove heat from the cold water in cold water loop  216 . Chiller subplant  206  is also shown to include several pumps  234  and  236  configured to circulate the cold water in cold water loop  216  and to control the flow rate of the cold water through individual chillers  232 . 
     Heat recovery chiller subplant  204  is shown to include a plurality of heat recovery heat exchangers  226  (e.g., refrigeration circuits) configured to transfer heat from cold water loop  216  to hot water loop  214 . Heat recovery chiller subplant  204  is also shown to include several pumps  228  and  230  configured to circulate the hot water and/or cold water through heat recovery heat exchangers  226  and to control the flow rate of the water through individual heat recovery heat exchangers  226 . Cooling tower subplant  208  is shown to include a plurality of cooling towers  238  configured to remove heat from the condenser water in condenser water loop  218 . Cooling tower subplant  208  is also shown to include several pumps  240  configured to circulate the condenser water in condenser water loop  218  and to control the flow rate of the condenser water through individual cooling towers  238 . 
     Hot TES subplant  210  is shown to include a hot TES tank  242  configured to store the hot water for later use. Hot TES subplant  210  may also include one or more pumps or valves configured to control the flow rate of the hot water into or out of hot TES tank  242 . Cold TES subplant  212  is shown to include cold TES tanks  244  configured to store the cold water for later use. Cold TES subplant  212  may also include one or more pumps or valves configured to control the flow rate of the cold water into or out of cold TES tanks  244 . 
     In some embodiments, one or more of the pumps in waterside system  200  (e.g., pumps  222 ,  224 ,  228 ,  230 ,  234 ,  236 , and/or  240 ) or pipelines in waterside system  200  include an isolation valve associated therewith. Isolation valves can be integrated with the pumps or positioned upstream or downstream of the pumps to control the fluid flows in waterside system  200 . In various embodiments, waterside system  200  can include more, fewer, or different types of devices and/or subplants based on the particular configuration of waterside system  200  and the types of loads served by waterside system  200 . 
     Airside System 
     Referring now to  FIG. 3 , a block diagram of an airside system  300  is shown, according to some embodiments. In various embodiments, airside system  300  may supplement or replace airside system  130  in HVAC system  100  or can be implemented separate from HVAC system  100 . When implemented in HVAC system  100 , airside system  300  can include a subset of the HVAC devices in HVAC system  100  (e.g., AHU  106 , VAV units  116 , ducts  112 - 114 , fans, dampers, etc.) and can be located in or around building  10 . Airside system  300  may operate to heat or cool an airflow provided to building  10  using a heated or chilled fluid provided by waterside system  200 . 
     In  FIG. 3 , airside system  300  is shown to include an economizer-type air handling unit (AHU)  302 . Economizer-type AHUs vary the amount of outside air and return air used by the air handling unit for heating or cooling. For example, AHU  302  may receive return air  304  from building zone  306  via return air duct  308  and may deliver supply air  310  to building zone  306  via supply air duct  312 . In some embodiments, AHU  302  is a rooftop unit located on the roof of building  10  (e.g., AHU  106  as shown in  FIG. 1 ) or otherwise positioned to receive both return air  304  and outside air  314 . AHU  302  can be configured to operate exhaust air damper  316 , mixing damper  318 , and outside air damper  320  to control an amount of outside air  314  and return air  304  that combine to form supply air  310 . Any return air  304  that does not pass through mixing damper  318  can be exhausted from AHU  302  through exhaust damper  316  as exhaust air  322 . 
     Each of dampers  316 - 320  can be operated by an actuator. For example, exhaust air damper  316  can be operated by actuator  324 , mixing damper  318  can be operated by actuator  326 , and outside air damper  320  can be operated by actuator  328 . Actuators  324 - 328  may communicate with an AHU controller  330  via a communications link  332 . Actuators  324 - 328  may receive control signals from AHU controller  330  and may provide feedback signals to AHU controller  330 . Feedback signals can include, for example, an indication of a current actuator or damper position, an amount of torque or force exerted by the actuator, diagnostic information (e.g., results of diagnostic tests performed by actuators  324 - 328 ), status information, commissioning information, configuration settings, calibration data, and/or other types of information or data that can be collected, stored, or used by actuators  324 - 328 . AHU controller  330  can be an economizer controller configured to use one or more control algorithms (e.g., state-based algorithms, extremum seeking control (ESC) algorithms, proportional-integral (PI) control algorithms, proportional-integral-derivative (PID) control algorithms, model predictive control (MPC) algorithms, feedback control algorithms, etc.) to control actuators  324 - 328 . 
     Still referring to  FIG. 3 , AHU  302  is shown to include a cooling coil  334 , a heating coil  336 , and a fan  338  positioned within supply air duct  312 . Fan  338  can be configured to force supply air  310  through cooling coil  334  and/or heating coil  336  and provide supply air  310  to building zone  306 . AHU controller  330  may communicate with fan  338  via communications link  340  to control a flow rate of supply air  310 . In some embodiments, AHU controller  330  controls an amount of heating or cooling applied to supply air  310  by modulating a speed of fan  338 . 
     Cooling coil  334  may receive a chilled fluid from waterside system  200  (e.g., from cold water loop  216 ) via piping  342  and may return the chilled fluid to waterside system  200  via piping  344 . Valve  346  can be positioned along piping  342  or piping  344  to control a flow rate of the chilled fluid through cooling coil  334 . In some embodiments, cooling coil  334  includes multiple stages of cooling coils that can be independently activated and deactivated (e.g., by AHU controller  330 , by BMS controller  366 , etc.) to modulate an amount of cooling applied to supply air  310 . 
     Heating coil  336  may receive a heated fluid from waterside system  200  (e.g., from hot water loop  214 ) via piping  348  and may return the heated fluid to waterside system  200  via piping  350 . Valve  352  can be positioned along piping  348  or piping  350  to control a flow rate of the heated fluid through heating coil  336 . In some embodiments, heating coil  336  includes multiple stages of heating coils that can be independently activated and deactivated (e.g., by AHU controller  330 , by BMS controller  366 , etc.) to modulate an amount of heating applied to supply air  310 . 
     Each of valves  346  and  352  can be controlled by an actuator. For example, valve  346  can be controlled by actuator  354  and valve  352  can be controlled by actuator  356 . Actuators  354 - 356  may communicate with AHU controller  330  via communications links  358 - 360 . Actuators  354 - 356  may receive control signals from AHU controller  330  and may provide feedback signals to controller  330 . In some embodiments, AHU controller  330  receives a measurement of the supply air temperature from a temperature sensor  362  positioned in supply air duct  312  (e.g., downstream of cooling coil  334  and/or heating coil  336 ). AHU controller  330  may also receive a measurement of the temperature of building zone  306  from a temperature sensor  364  located in building zone  306 . 
     In some embodiments, AHU controller  330  operates valves  346  and  352  via actuators  354 - 356  to modulate an amount of heating or cooling provided to supply air  310  (e.g., to achieve a setpoint temperature for supply air  310  or to maintain the temperature of supply air  310  within a setpoint temperature range). The positions of valves  346  and  352  affect the amount of heating or cooling provided to supply air  310  by cooling coil  334  or heating coil  336  and may correlate with the amount of energy consumed to achieve a desired supply air temperature. AHU  330  may control the temperature of supply air  310  and/or building zone  306  by activating or deactivating coils  334 - 336 , adjusting a speed of fan  338 , or a combination of both. 
     Still referring to  FIG. 3 , airside system  300  is shown to include a building management system (BMS) controller  366  and a client device  368 . BMS controller  366  can include one or more computer systems (e.g., servers, supervisory controllers, subsystem controllers, etc.) that serve as system level controllers, application or data servers, head nodes, or master controllers for airside system  300 , waterside system  200 , HVAC system  100 , and/or other controllable systems that serve building  10 . BMS controller  366  may communicate with multiple downstream building systems or subsystems (e.g., HVAC system  100 , a security system, a lighting system, waterside system  200 , etc.) via a communications link  370  according to like or disparate protocols (e.g., LON, BACnet, etc.). In various embodiments, AHU controller  330  and BMS controller  366  can be separate (as shown in  FIG. 3 ) or integrated. In an integrated implementation, AHU controller  330  can be a software module configured for execution by a processor of BMS controller  366 . 
     In some embodiments, AHU controller  330  receives information from BMS controller  366  (e.g., commands, setpoints, operating boundaries, etc.) and provides information to BMS controller  366  (e.g., temperature measurements, valve or actuator positions, operating statuses, diagnostics, etc.). For example, AHU controller  330  may provide BMS controller  366  with temperature measurements from temperature sensors  362 - 364 , equipment on/off states, equipment operating capacities, and/or any other information that can be used by BMS controller  366  to monitor or control a variable state or condition within building zone  306 . 
     Client device  368  can include one or more human-machine interfaces or client interfaces (e.g., graphical user interfaces, reporting interfaces, text-based computer interfaces, client-facing web services, web servers that provide pages to web clients, etc.) for controlling, viewing, or otherwise interacting with HVAC system  100 , its subsystems, and/or devices. Client device  368  can be a computer workstation, a client terminal, a remote or local interface, or any other type of user interface device. Client device  368  can be a stationary terminal or a mobile device. For example, client device  368  can be a desktop computer, a computer server with a user interface, a laptop computer, a tablet, a smartphone, a PDA, or any other type of mobile or non-mobile device. Client device  368  may communicate with BMS controller  366  and/or AHU controller  330  via communications link  372 . 
     Building Management Systems 
     Referring now to  FIG. 4 , a block diagram of a building management system (BMS)  400  is shown, according to some embodiments. BMS  400  can be implemented in building  10  to automatically monitor and control various building functions. BMS  400  is shown to include BMS controller  366  and a plurality of building subsystems  428 . Building subsystems  428  are shown to include a building electrical subsystem  434 , an information communication technology (ICT) subsystem  436 , a security subsystem  438 , a HVAC subsystem  440 , a lighting subsystem  442 , a lift/escalators subsystem  432 , and a fire safety subsystem  430 . In various embodiments, building subsystems  428  can include fewer, additional, or alternative subsystems. For example, building subsystems  428  may also or alternatively include a refrigeration subsystem, an advertising or signage subsystem, a cooking subsystem, a vending subsystem, a printer or copy service subsystem, or any other type of building subsystem that uses controllable equipment and/or sensors to monitor or control building  10 . In some embodiments, building subsystems  428  include waterside system  200  and/or airside system  300 , as described with reference to  FIGS. 2-3 . 
     Each of building subsystems  428  can include any number of devices, controllers, and connections for completing its individual functions and control activities. HVAC subsystem  440  can include many of the same components as HVAC system  100 , as described with reference to  FIGS. 1-3 . For example, HVAC subsystem  440  can include a chiller, a boiler, any number of air handling units, economizers, field controllers, supervisory controllers, actuators, temperature sensors, and other devices for controlling the temperature, humidity, airflow, or other variable conditions within building  10 . Lighting subsystem  442  can include any number of light fixtures, ballasts, lighting sensors, dimmers, or other devices configured to controllably adjust the amount of light provided to a building space. Security subsystem  438  can include occupancy sensors, video surveillance cameras, digital video recorders, video processing servers, intrusion detection devices, access control devices and servers, or other security-related devices. 
     Still referring to  FIG. 4 , BMS controller  366  is shown to include a communications interface  407  and a BMS interface  409 . Interface  407  may facilitate communications between BMS controller  366  and external applications (e.g., monitoring and reporting applications  422 , enterprise control applications  426 , remote systems and applications  444 , applications residing on client devices  448 , etc.) for allowing user control, monitoring, and adjustment to BMS controller  366  and/or subsystems  428 . Interface  407  may also facilitate communications between BMS controller  366  and client devices  448 . BMS interface  409  may facilitate communications between BMS controller  366  and building subsystems  428  (e.g., HVAC, lighting security, lifts, power distribution, business, etc.). 
     Interfaces  407 ,  409  can be or include wired or wireless communications interfaces (e.g., jacks, antennas, transmitters, receivers, transceivers, wire terminals, etc.) for conducting data communications with building subsystems  428  or other external systems or devices. In various embodiments, communications via interfaces  407 ,  409  can be direct (e.g., local wired or wireless communications) or via a communications network  446  (e.g., a WAN, the Internet, a cellular network, etc.). For example, interfaces  407 ,  409  can include an Ethernet card and port for sending and receiving data via an Ethernet-based communications link or network. In another example, interfaces  407 ,  409  can include a Wi-Fi transceiver for communicating via a wireless communications network. In another example, one or both of interfaces  407 ,  409  can include cellular or mobile phone communications transceivers. In one embodiment, communications interface  407  is a power line communications interface and BMS interface  409  is an Ethernet interface. In other embodiments, both communications interface  407  and BMS interface  409  are Ethernet interfaces or are the same Ethernet interface. 
     Still referring to  FIG. 4 , BMS controller  366  is shown to include a processing circuit  404  including a processor  406  and memory  408 . Processing circuit  404  can be communicably connected to BMS interface  409  and/or communications interface  407  such that processing circuit  404  and the various components thereof can send and receive data via interfaces  407 ,  409 . Processor  406  can be implemented as a general purpose processor, an application specific integrated circuit (ASIC), one or more field programmable gate arrays (FPGAs), a group of processing components, or other suitable electronic processing components. 
     Memory  408  (e.g., memory, memory unit, storage device, etc.) can include one or more devices (e.g., RAM, ROM, Flash memory, hard disk storage, etc.) for storing data and/or computer code for completing or facilitating the various processes, layers and modules described in the present application. Memory  408  can be or include volatile memory or non-volatile memory. Memory  408  can include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described in the present application. According to some embodiments, memory  408  is communicably connected to processor  406  via processing circuit  404  and includes computer code for executing (e.g., by processing circuit  404  and/or processor  406 ) one or more processes described herein. 
     In some embodiments, BMS controller  366  is implemented within a single computer (e.g., one server, one housing, etc.). In various other embodiments BMS controller  366  can be distributed across multiple servers or computers (e.g., that can exist in distributed locations). Further, while  FIG. 4  shows applications  422  and  426  as existing outside of BMS controller  366 , in some embodiments, applications  422  and  426  can be hosted within BMS controller  366  (e.g., within memory  408 ). 
     Still referring to  FIG. 4 , memory  408  is shown to include an enterprise integration layer  410 , an automated measurement and validation (AM&amp;V) layer  412 , a demand response (DR) layer  414 , a fault detection and diagnostics (FDD) layer  416 , an integrated control layer  418 , and a building subsystem integration later  420 . Layers  410 - 420  can be configured to receive inputs from building subsystems  428  and other data sources, determine optimal control actions for building subsystems  428  based on the inputs, generate control signals based on the optimal control actions, and provide the generated control signals to building subsystems  428 . The following paragraphs describe some of the general functions performed by each of layers  410 - 420  in BMS  400 . 
     Enterprise integration layer  410  can be configured to serve clients or local applications with information and services to support a variety of enterprise-level applications. For example, enterprise control applications  426  can be configured to provide subsystem-spanning control to a graphical user interface (GUI) or to any number of enterprise-level business applications (e.g., accounting systems, user identification systems, etc.). Enterprise control applications  426  may also or alternatively be configured to provide configuration GUIs for configuring BMS controller  366 . In yet other embodiments, enterprise control applications  426  can work with layers  410 - 420  to optimize building performance (e.g., efficiency, energy use, comfort, or safety) based on inputs received at interface  407  and/or BMS interface  409 . 
     Building subsystem integration layer  420  can be configured to manage communications between BMS controller  366  and building subsystems  428 . For example, building subsystem integration layer  420  may receive sensor data and input signals from building subsystems  428  and provide output data and control signals to building subsystems  428 . Building subsystem integration layer  420  may also be configured to manage communications between building subsystems  428 . Building subsystem integration layer  420  translate communications (e.g., sensor data, input signals, output signals, etc.) across a plurality of multi-vendor/multi-protocol systems. 
     Demand response layer  414  can be configured to optimize resource usage (e.g., electricity use, natural gas use, water use, etc.) and/or the monetary cost of such resource usage in response to satisfy the demand of building  10 . The optimization can be based on time-of-use prices, curtailment signals, energy availability, or other data received from utility providers, distributed energy generation systems  424 , from energy storage  427  (e.g., hot TES  242 , cold TES  244 , etc.), or from other sources. Demand response layer  414  may receive inputs from other layers of BMS controller  366  (e.g., building subsystem integration layer  420 , integrated control layer  418 , etc.). The inputs received from other layers can include environmental or sensor inputs such as temperature, carbon dioxide levels, relative humidity levels, air quality sensor outputs, occupancy sensor outputs, room schedules, and the like. The inputs may also include inputs such as electrical use (e.g., expressed in kWh), thermal load measurements, pricing information, projected pricing, smoothed pricing, curtailment signals from utilities, and the like. 
     According to some embodiments, demand response layer  414  includes control logic for responding to the data and signals it receives. These responses can include communicating with the control algorithms in integrated control layer  418 , changing control strategies, changing setpoints, or activating/deactivating building equipment or subsystems in a controlled manner. Demand response layer  414  may also include control logic configured to determine when to utilize stored energy. For example, demand response layer  414  may determine to begin using energy from energy storage  427  just prior to the beginning of a peak use hour. 
     In some embodiments, demand response layer  414  includes a control module configured to actively initiate control actions (e.g., automatically changing setpoints) which minimize energy costs based on one or more inputs representative of or based on demand (e.g., price, a curtailment signal, a demand level, etc.). In some embodiments, demand response layer  414  uses equipment models to determine an optimal set of control actions. The equipment models can include, for example, thermodynamic models describing the inputs, outputs, and/or functions performed by various sets of building equipment. Equipment models may represent collections of building equipment (e.g., subplants, chiller arrays, etc.) or individual devices (e.g., individual chillers, heaters, pumps, etc.). 
     Demand response layer  414  may further include or draw upon one or more demand response policy definitions (e.g., databases, XML, files, etc.). The policy definitions can be edited or adjusted by a user (e.g., via a graphical user interface) so that the control actions initiated in response to demand inputs can be tailored for the user&#39;s application, desired comfort level, particular building equipment, or based on other concerns. For example, the demand response policy definitions can specify which equipment can be turned on or off in response to particular demand inputs, how long a system or piece of equipment should be turned off, what setpoints can be changed, what the allowable set point adjustment range is, how long to hold a high demand setpoint before returning to a normally scheduled setpoint, how close to approach capacity limits, which equipment modes to utilize, the energy transfer rates (e.g., the maximum rate, an alarm rate, other rate boundary information, etc.) into and out of energy storage devices (e.g., thermal storage tanks, battery banks, etc.), and when to dispatch on-site generation of energy (e.g., via fuel cells, a motor generator set, etc.). 
     Integrated control layer  418  can be configured to use the data input or output of building subsystem integration layer  420  and/or demand response later  414  to make control decisions. Due to the subsystem integration provided by building subsystem integration layer  420 , integrated control layer  418  can integrate control activities of the subsystems  428  such that the subsystems  428  behave as a single integrated supersystem. In some embodiments, integrated control layer  418  includes control logic that uses inputs and outputs from a plurality of building subsystems to provide greater comfort and energy savings relative to the comfort and energy savings that separate subsystems could provide alone. For example, integrated control layer  418  can be configured to use an input from a first subsystem to make an energy-saving control decision for a second subsystem. Results of these decisions can be communicated back to building subsystem integration layer  420 . 
     Integrated control layer  418  is shown to be logically below demand response layer  414 . Integrated control layer  418  can be configured to enhance the effectiveness of demand response layer  414  by enabling building subsystems  428  and their respective control loops to be controlled in coordination with demand response layer  414 . This configuration may advantageously reduce disruptive demand response behavior relative to conventional systems. For example, integrated control layer  418  can be configured to assure that a demand response-driven upward adjustment to the setpoint for chilled water temperature (or another component that directly or indirectly affects temperature) does not result in an increase in fan energy (or other energy used to cool a space) that would result in greater total building energy use than was saved at the chiller. 
     Integrated control layer  418  can be configured to provide feedback to demand response layer  414  so that demand response layer  414  checks that constraints (e.g., temperature, lighting levels, etc.) are properly maintained even while demanded load shedding is in progress. The constraints may also include setpoint or sensed boundaries relating to safety, equipment operating limits and performance, comfort, fire codes, electrical codes, energy codes, and the like. Integrated control layer  418  is also logically below fault detection and diagnostics layer  416  and automated measurement and validation layer  412 . Integrated control layer  418  can be configured to provide calculated inputs (e.g., aggregations) to these higher levels based on outputs from more than one building subsystem. 
     Automated measurement and validation (AM&amp;V) layer  412  can be configured to verify that control strategies commanded by integrated control layer  418  or demand response layer  414  are working properly (e.g., using data aggregated by AM&amp;V layer  412 , integrated control layer  418 , building subsystem integration layer  420 , FDD layer  416 , or otherwise). The calculations made by AM&amp;V layer  412  can be based on building system energy models and/or equipment models for individual BMS devices or subsystems. For example, AM&amp;V layer  412  may compare a model-predicted output with an actual output from building subsystems  428  to determine an accuracy of the model. 
     Fault detection and diagnostics (FDD) layer  416  can be configured to provide on-going fault detection for building subsystems  428 , building subsystem devices (i.e., building equipment), and control algorithms used by demand response layer  414  and integrated control layer  418 . FDD layer  416  may receive data inputs from integrated control layer  418 , directly from one or more building subsystems or devices, or from another data source. FDD layer  416  may automatically diagnose and respond to detected faults. The responses to detected or diagnosed faults can include providing an alert message to a user, a maintenance scheduling system, or a control algorithm configured to attempt to repair the fault or to work-around the fault. 
     FDD layer  416  can be configured to output a specific identification of the faulty component or cause of the fault (e.g., loose damper linkage) using detailed subsystem inputs available at building subsystem integration layer  420 . In other exemplary embodiments, FDD layer  416  is configured to provide “fault” events to integrated control layer  418  which executes control strategies and policies in response to the received fault events. According to some embodiments, FDD layer  416  (or a policy executed by an integrated control engine or business rules engine) may shut-down systems or direct control activities around faulty devices or systems to reduce energy waste, extend equipment life, or assure proper control response. 
     FDD layer  416  can be configured to store or access a variety of different system data stores (or data points for live data). FDD layer  416  may use some content of the data stores to identify faults at the equipment level (e.g., specific chiller, specific AHU, specific terminal unit, etc.) and other content to identify faults at component or subsystem levels. For example, building subsystems  428  may generate temporal (i.e., time-series) data indicating the performance of BMS  400  and the various components thereof. The data generated by building subsystems  428  can include measured or calculated values that exhibit statistical characteristics and provide information about how the corresponding system or process (e.g., a temperature control process, a flow control process, etc.) is performing in terms of error from its setpoint. These processes can be examined by FDD layer  416  to expose when the system begins to degrade in performance and alert a user to repair the fault before it becomes more severe. 
     Referring now to  FIG. 5 , a block diagram of another building management system (BMS)  500  is shown, according to some embodiments. BMS  500  can be used to monitor and control the devices of HVAC system  100 , waterside system  200 , airside system  300 , building subsystems  428 , as well as other types of BMS devices (e.g., lighting equipment, security equipment, etc.) and/or HVAC equipment. 
     BMS  500  provides a system architecture that facilitates automatic equipment discovery and equipment model distribution. Equipment discovery can occur on multiple levels of BMS  500  across multiple different communications busses (e.g., a system bus  554 , zone buses  556 - 560  and  564 , sensor/actuator bus  566 , etc.) and across multiple different communications protocols. In some embodiments, equipment discovery is accomplished using active node tables, which provide status information for devices connected to each communications bus. For example, each communications bus can be monitored for new devices by monitoring the corresponding active node table for new nodes. When a new device is detected, BMS  500  can begin interacting with the new device (e.g., sending control signals, using data from the device) without user interaction. 
     Some devices in BMS  500  present themselves to the network using equipment models. An equipment model defines equipment object attributes, view definitions, schedules, trends, and the associated BACnet value objects (e.g., analog value, binary value, multistate value, etc.) that are used for integration with other systems. Some devices in BMS  500  store their own equipment models. Other devices in BMS  500  have equipment models stored externally (e.g., within other devices). For example, a zone coordinator  508  can store the equipment model for a bypass damper  528 . In some embodiments, zone coordinator  508  automatically creates the equipment model for bypass damper  528  or other devices on zone bus  558 . Other zone coordinators can also create equipment models for devices connected to their zone busses. The equipment model for a device can be created automatically based on the types of data points exposed by the device on the zone bus, device type, and/or other device attributes. Several examples of automatic equipment discovery and equipment model distribution are discussed in greater detail below. 
     Still referring to  FIG. 5 , BMS  500  is shown to include a system manager  502 ; several zone coordinators  506 ,  508 ,  510  and  518 ; and several zone controllers  524 ,  530 ,  532 ,  536 ,  548 , and  550 . System manager  502  can monitor data points in BMS  500  and report monitored variables to various monitoring and/or control applications. System manager  502  can communicate with client devices  504  (e.g., user devices, desktop computers, laptop computers, mobile devices, etc.) via a data communications link  574  (e.g., BACnet IP, Ethernet, wired or wireless communications, etc.). System manager  502  can provide a user interface to client devices  504  via data communications link  574 . The user interface may allow users to monitor and/or control BMS  500  via client devices  504 . 
     In some embodiments, system manager  502  is connected with zone coordinators  506 - 510  and  518  via a system bus  554 . System manager  502  can be configured to communicate with zone coordinators  506 - 510  and  518  via system bus  554  using a master-slave token passing (MSTP) protocol or any other communications protocol. System bus  554  can also connect system manager  502  with other devices such as a constant volume (CV) rooftop unit (RTU)  512 , an input/output module (TOM)  514 , a thermostat controller  516  (e.g., a TEC5000 series thermostat controller), and a network automation engine (NAE) or third-party controller  520 . RTU  512  can be configured to communicate directly with system manager  502  and can be connected directly to system bus  554 . Other RTUs can communicate with system manager  502  via an intermediate device. For example, a wired input  562  can connect a third-party RTU  542  to thermostat controller  516 , which connects to system bus  554 . 
     System manager  502  can provide a user interface for any device containing an equipment model. Devices such as zone coordinators  506 - 510  and  518  and thermostat controller  516  can provide their equipment models to system manager  502  via system bus  554 . In some embodiments, system manager  502  automatically creates equipment models for connected devices that do not contain an equipment model (e.g., IOM  514 , third party controller  520 , etc.). For example, system manager  502  can create an equipment model for any device that responds to a device tree request. The equipment models created by system manager  502  can be stored within system manager  502 . System manager  502  can then provide a user interface for devices that do not contain their own equipment models using the equipment models created by system manager  502 . In some embodiments, system manager  502  stores a view definition for each type of equipment connected via system bus  554  and uses the stored view definition to generate a user interface for the equipment. 
     Each zone coordinator  506 - 510  and  518  can be connected with one or more of zone controllers  524 ,  530 - 532 ,  536 , and  548 - 550  via zone buses  556 ,  558 ,  560 , and  564 . Zone coordinators  506 - 510  and  518  can communicate with zone controllers  524 ,  530 - 532 ,  536 , and  548 - 550  via zone busses  556 - 560  and  564  using a MSTP protocol or any other communications protocol. Zone busses  556 - 560  and  564  can also connect zone coordinators  506 - 510  and  518  with other types of devices such as variable air volume (VAV) RTUs  522  and  540 , changeover bypass (COBP) RTUs  526  and  552 , bypass dampers  528  and  546 , and PEAK controllers  534  and  544 . 
     Zone coordinators  506 - 510  and  518  can be configured to monitor and command various zoning systems. In some embodiments, each zone coordinator  506 - 510  and  518  monitors and commands a separate zoning system and is connected to the zoning system via a separate zone bus. For example, zone coordinator  506  can be connected to VAV RTU  522  and zone controller  524  via zone bus  556 . Zone coordinator  508  can be connected to COBP RTU  526 , bypass damper  528 , COBP zone controller  530 , and VAV zone controller  532  via zone bus  558 . Zone coordinator  510  can be connected to PEAK controller  534  and VAV zone controller  536  via zone bus  560 . Zone coordinator  518  can be connected to PEAK controller  544 , bypass damper  546 , COBP zone controller  548 , and VAV zone controller  550  via zone bus  564 . 
     A single model of zone coordinator  506 - 510  and  518  can be configured to handle multiple different types of zoning systems (e.g., a VAV zoning system, a COBP zoning system, etc.). Each zoning system can include a RTU, one or more zone controllers, and/or a bypass damper. For example, zone coordinators  506  and  510  are shown as Verasys VAV engines (VVEs) connected to VAV RTUs  522  and  540 , respectively. Zone coordinator  506  is connected directly to VAV RTU  522  via zone bus  556 , whereas zone coordinator  510  is connected to a third-party VAV RTU  540  via a wired input  568  provided to PEAK controller  534 . Zone coordinators  508  and  518  are shown as Verasys COBP engines (VCEs) connected to COBP RTUs  526  and  552 , respectively. Zone coordinator  508  is connected directly to COBP RTU  526  via zone bus  558 , whereas zone coordinator  518  is connected to a third-party COBP RTU  552  via a wired input  570  provided to PEAK controller  544 . 
     Zone controllers  524 ,  530 - 532 ,  536 , and  548 - 550  can communicate with individual BMS devices (e.g., sensors, actuators, etc.) via sensor/actuator (SA) busses. For example, VAV zone controller  536  is shown connected to networked sensors  538  via SA bus  566 . Zone controller  536  can communicate with networked sensors  538  using a MSTP protocol or any other communications protocol. Although only one SA bus  566  is shown in  FIG. 5 , it should be understood that each zone controller  524 ,  530 - 532 ,  536 , and  548 - 550  can be connected to a different SA bus. Each SA bus can connect a zone controller with various sensors (e.g., temperature sensors, humidity sensors, pressure sensors, light sensors, occupancy sensors, etc.), actuators (e.g., damper actuators, valve actuators, etc.) and/or other types of controllable equipment (e.g., chillers, heaters, fans, pumps, etc.). 
     Each zone controller  524 ,  530 - 532 ,  536 , and  548 - 550  can be configured to monitor and control a different building zone. Zone controllers  524 ,  530 - 532 ,  536 , and  548 - 550  can use the inputs and outputs provided via their SA busses to monitor and control various building zones. For example, a zone controller  536  can use a temperature input received from networked sensors  538  via SA bus  566  (e.g., a measured temperature of a building zone) as feedback in a temperature control algorithm. Zone controllers  524 ,  530 - 532 ,  536 , and  548 - 550  can use various types of control algorithms (e.g., state-based algorithms, extremum seeking control (ESC) algorithms, proportional-integral (PI) control algorithms, proportional-integral-derivative (PID) control algorithms, model predictive control (MPC) algorithms, feedback control algorithms, etc.) to control a variable state or condition (e.g., temperature, humidity, airflow, lighting, etc.) in or around building  10 . 
     Point Virtualization Under Online Meters 
     Referring now to  FIG. 6-10 , several drawings illustrating systems and methods for point virtualization under online meters in a BMS are shown. In some embodiments, the point virtualization systems and methods described herein are implemented with BMS  400  or BMS  500 , as described with reference to  FIGS. 4-5 . 
     Referring now to  FIG. 6 , a block diagram of a BMS  600  with point virtualization is shown. The BMS  600  includes multiple meters  602  that provide data samples for multiple real points measured by the meters  602  (e.g., collected by sensors included with the meters  602 ). As used herein, the term “real point” refers to a point that is measured or observed by one or more of the meters  602 . A real point may represent a physical parameter of the building and/or building equipment served by BMS  600  (e.g., a temperature point measured by a temperature sensor of the meters  602 , a power consumption measured by a power meter of the meters  602 , a flow rate measured by a flow meter of the meters  602 , etc.). Accordingly, the meters  602  provide raw data for real points corresponding to physical parameters of the building and/or building equipment served by the BMS  600 . Conversely, the term “virtual point” refers to a point that is not directly measured by the meters  602  but rather is calculated or simulated based on one or more real points, other virtual points, and/or other parameters or values. 
     In many cases the real points measured by the meters  602  are not sufficient to allow the BMS  600  to calculate all metrics, key performance indicators, etc. desired by users of the BMS  600  or necessary for implementing various features of the BMS  600 . Thus, as described in detail below, the BMS  600  provides for point virtualization under online meters  602  to provide an efficient, user-friendly, and cost-effective way to cover for deficiencies in the amount or type of data provided by the meters  602 . 
     As shown in  FIG. 6 , the BMS  600  includes an analytics system  604  that facilitates point virtualization and provides for the calculation of advanced metrics (e.g., key performance indicators) based on both real points and virtual points. In some embodiments, the analytics system  604  is a component of BMS  400  or BMS  500 , for example included with system manager  502 . As illustrated in  FIG. 6 , the analytics system  604  includes an object database  606 , a point virtualization circuit  608 , and an advanced metrics circuit  610 . 
     The object database  606  is configured to store data objects corresponding to various elements and features of the BMS  600 , for example meter objects  612  and point objects  614 . Each meter object  612  is an electronic representation of one of the meters  602  in the BMS  600 , and each point object  614  is an electronic representation of a real point (i.e., corresponding to a real-world measurement from a meter  602 ) or virtual point (i.e., corresponding to a simulated value not provided directly by a meter  602 ). Each point object  614  includes a set of attributes associated with the corresponding point, and each meter object includes a set of attributes associated with the corresponding meter, as illustrated in  FIG. 7  and described with reference thereto below. For example, as an attribute of each meter object, the object database  606  may store a list of points associated with that meter. 
     The point virtualization circuit  608  is configured to create virtual point objects, store virtual point objects in the object database  606  as point objects  614 , and alter the attributes of the meter objects  612  to list virtual point objects  614  as associated with meter objects  612 , for example as described with reference to  FIG. 8  below. The point virtualization circuit  608  thereby facilitates the creation of virtual points under online meters, i.e., such that a meter  602  may be associated with both real points and virtual points. The point virtualization circuit  608  may also communicate with a user device (shown as client device  504 ). The point virtualization circuit  608  may generate a user interface for presentation on the user device (e.g., tablet, laptop, desktop computer, smartphone) that allows the user to request the creation of new virtual points, map virtual points to meters  602 , and define derivation formulas for virtual point objects. Examples of such graphical user interfaces are shown in  FIGS. 9-11  and described in detail with reference thereto. 
     The advanced metrics circuit  610  is configured to calculate metrics (e.g., key performance indicators, roll-ups, space aggregations, fault detection and diagnostics) relating to the building and/or building equipment served by the BMS  600 . The advanced metrics circuit  610  may receive data from the meters  602  and determine a value for each point associated with each meter, including both virtual points and real points. The advanced metrics circuit  610  may then treat virtual points and real points identically to calculate metrics based on the values of the points. This may allow the advanced metrics circuit  610  to calculate all desired metrics even where the real points do not directly correspond to the inputs necessary to calculate that metric and without regard to whether the metric is calculated from real points, virtual points, or some combination thereof. In some embodiments, the advanced metrics circuit  610  may receive a request to calculate a metric from a client device  504 , calculate the metric in response, and provide the metric to the client device  504  for presentation in a graphical user interface. 
     As one illustrative example, a building may include a first space served by a first meter and a second space served by a second meter. The first meter may collect a first real point for the first space corresponding to a physical parameter (e.g., power consumption), but the second meter may not be configured to collect data for that physical parameter. In such a situation, a second virtual point corresponding to the physical parameter in the second space may be created under the second meter by creating a virtual point object associated with a meter object for the second meter. Then, the advanced metrics circuit  610  may calculate an aggregate metric for the building (i.e., for the first space and the second space) using data for the first real point and data for the second virtual point. For example, the advanced metrics circuit  610  may add a value of the first real point to a value of second virtual point to determine a total value for the building. 
     Referring now to  FIG. 7 , a block diagram of the object database  606  of the BMS  600  is shown, according to an exemplary embodiment. In some embodiments, the object database  606  is a component of BMS  400  or BMS  500 . The object database  606  can store meter objects  612  corresponding to each physical meter deployed in the buildings or facilities managed by the BMS  600 , illustrated by an example meter object  616  in  FIG. 7 . The meter object  616  may include meter attributes including, for example, the meter name (e.g., “M1”), meter location (e.g., “Building 1—Floor 4”), and/or the points provided by that meter (e.g., “p1,” “p2,” and “p3”). The points listed in the meter object  616  may include both real points (i.e., points directly collected by the physical meter  602 ) and virtual points (i.e., simulated points calculated indirectly from data collected by one or more meters  602 ). 
     The object database  606  can also store a point object for each of one or more points, including real points provided by a meter  602  and virtual points associated with a meter  602  in the object database  606 .  FIG. 6  illustrates an example in which three point objects  618 ,  620 , and  622  (representing points “p1,” “p2,” and “p3” respectively) are associated with a meter object  616  (representing meter “M1”). Each point object  618 - 622  includes attributes for the corresponding point, for example the point name, the point location, the point&#39;s units, and point type. The point type may indicate whether the point corresponds to a physical measurement or the point is a virtual point simulated within the BMS  600 . For a real point (i.e., a point corresponding to a physical measurement), the point object  618 - 620  may include the point source, indicating the meter associated with the point. For a virtual point, the point object  622  may include a derivation formula which defines how a data series associated with the virtual point is derived from data associated with other points, from a model or simulation, or from based on some other dataset. 
       FIG. 7  illustrates that the points attribute of the meter object  616  may list both real points and virtual points. In the example shown, points “p1” and “p2” are real points whereas point “p3” is a virtual point. As shown, by listing real points and virtual points together in the points attribute, the meter object  616  treats real and virtual point objects identically and makes no differentiation between real and virtual points. Virtual point objects such as point object  622  need not be organized or stored under separate virtual meter objects or otherwise differentiated at the level of the meter objects  612 . Instead, a virtual point object  622  is included under the meter object  616  to associate the virtual point p3 with a physical meter M1, which is referred to herein as point virtualization under online meters. The BMS  600  (e.g., the advanced metrics circuit  610 ) may then use a virtual point like any other point in calculating meter roll-ups and key performance indicators and generating displays of meter information for users. Point virtualization under online meters thereby facilitates calculation of metrics that require points not provided by real meters, improves efficiency and reduces complexity relative to other potential ways to simulate points (e.g., by creating virtual meters), and provides an intuitive framework that facilitates a user in understanding and configuring virtual points. 
     Referring now to  FIG. 8 , a flowchart of a process  800  for point virtualization under online meters is shown, according to an exemplary embodiment. At step  802 , the analytics system  604  associates a real point object for a real point with a meter object for an online meter  602 . The analytics system  604  stores the real point object and the meter object in an object database  606 . In some embodiments, the analytics system  604  associates the real point object with the meter object by listing the real point object or a designation thereof (e.g., point name) in a points attribute of the meter object. In some embodiments, the analytics system  604  associates the real point object with the meter object by listing the meter object or a designation thereof (e.g., meter name) in a meter attribute of the point objects. 
     At step  804 , a virtual point is defined in the analytics system  604 , for example by a formula or other algorithm for calculating a value of the virtual point. For example, the virtual point may be defined as a function of real points, such that a value of the virtual point at a given time step may be calculated based on the values of real points for that time step (i.e., based on data collected by meters  602 ). The virtual point may also, or alternatively, be defined to have a value generated by some other simulation, model, dataset, etc. In some embodiments, the analytics system  604  receives user input defining the virtual point from a client device  504 , for example as described with reference to  FIGS. 9-11  below. 
     At step  806 , the analytics system  604  associates the virtual point with the meter object. The analytics system  604  may associate the virtual point with the meter object by listing the virtual point in an attribute of the meter object (e.g., a points attribute that lists the points associated with the meter, including both virtual points and real points). The meter object may thereby treat virtual points and real points identically. Higher-level calculations, roll-ups, etc. may then simply deal with all points in a similar or identical way, avoiding any computational complexity and expense that may be created by other approaches to point virtualization. 
     At step  808 , the analytics system  604  receives a data sample from an online meter  602  for the real point. For example, the analytics system  604  receives an analog or digital signal, measurement, data value, sample, or other value of the real point from the online meter  602  associated with the real point. At step  810 , the analytics system  604  assigns a value for the real point based on the data sample. For example, in an embodiment where the data sample is an analog signal, the analytics system  604  may determine a digital representation of a numerical value of the real point based on the data sample and store that representation as the value of the real point. 
     At step  812 , a value for the virtual point is calculated based on the definition of the virtual point created at step  804 . For example, the virtual point may be calculated based on the data sample for the real point and/or based on data from other meters and/or other data sources (e.g., a weather forecast system, a building model simulation, a building schedule, etc.). For example, a virtual enthalpy point that represents the enthalpy of a fluid can be calculated based on real points that represent the temperature and pressure of the fluid. 
     At step  814 , the value for the real point from step  810  and the value for the virtual point from step  812  are associated with the meter  602 . That is, based on the association of the real point and the virtual point with the meter  602  represented by the meter object (i.e., as created at step  802 ), the analytics system  604  associates the values for the real point and the virtual point with the meter  602 . At step  816 , the analytics system  604  calculates a metric based on the values associated with the meter  602 , i.e., the value of the real point and the value of the virtual point. For example, the analytics system  604  may add, multiply, average, or perform other mathematical operations on the values to calculate the metric. As another example, the values associated with the meter  602  may be used with values associated with one or more additional meters  602  to calculate a metric or a key performance indicator, or to generate a graphical representation of the operation of building equipment. In all such calculations, the analytics system  604  treats the values in a substantially identical way, i.e., without regard to the real or virtual nature of the points. 
     Referring now to  FIG. 9 , a meter configuration interface  900  for mapping and creating points under an online meter is shown, according to an exemplary embodiment. The meter configuration interface  900  may be generated by the analytics system  604  (e.g., by the point virtualization circuit  608 ) of  FIG. 6 . The meter configuration interface  900  includes a points tree widget  902 , a meter distribution tree widget  904 , and a meter details widget  906 . 
     The points tree widget  902  includes search features  908 , for example including drop down selections, list toggles, and/or a text search feature to allow a user to find and select any point already created in the BMS  600 . Search results may be presented in the points tree widget  902 . The points tree widget  902  thereby allows a user to search for and then select a point to add the point to a meter using the meter distribution tree widget  904   
     The meter distribution tree widget  904  provides a collapsible list  910  of facilities and buildings. The collapsible list  910  indicates that within each building are subcategories of building infrastructure (e.g., electricity, weather) or building subspaces (e.g., Floor 2). The collapsible list  910  further includes entries for meters located with the appropriate subcategory. Listed meters may include a status indicator  912  that shows whether the meter is online, offline, or virtual. A meter may be selected in order to add or delete a point under that meter. In some embodiments, the meter distribution tree widget  904  allows the user to move the meter to a different subcategory, building, or facility to reassign the meter. In some embodiments, the meter distribution tree widget  904  allows the user to delete the meter from the collapsible list  910 . 
     The meter details widget  906  allows a user to add a new meter, a new virtual point, or a new online point. The meter details widget  906  includes a type selection  914  that allows a user to select whether they want to add a new meter, a new virtual point, or a new online point. When the user selects to add a new virtual point, the meter details widget displays entry fields  916  that accept input of a point name, a point description, a unit type, a unit, a point role, and a series type. Some input fields may be indicated as optional, while others may be indicated as required for point creation. The meter details widget may also include a virtual point definition button  918 , which is configured to open a virtual point definition widget  1000  (shown in  FIG. 10 ) when selected by a user. 
     Referring now to  FIG. 10 , a virtual point definition widget  1000  is shown. Virtual point definition widget  1000  may be generated by the analytics system  604  (e.g., by the point virtualization circuit  608 ) of  FIG. 6 . The virtual point definition widget  1000  may include an equipment and meter tree  1002  that lists all equipment, meters, and existing points, organized hierarchically. The virtual point definition widget  1000  also includes a formula entry portal  1004 . The formula entry portal  1004  includes a formula field  1006 , a numeric value entry field  1008 , and operator buttons  1010 . A user may create a formula by selecting a point from the equipment and meter tree  1002  to add the point to the formula field  1006 . The user may then select operator buttons  1010  to input mathematical operators (e.g., addition, multiplication, division) or logical operators (e.g., OR, AND, NOT, IF, &lt;, &gt;) to the formula field. The user may also input constant numeric values into the formula field using the numeric value entry field  1008 . The user may enter multiple existing points, multiple mathematical and logical operators, and multiple constant numerical values into the formula field  1006  to craft a derivation formula for calculating the data output of the new virtual point. 
     The virtual point definition widget  1000  may also include a validate syntax button  1012 . When the validate syntax button  1012  is selected, the analytics system  604  may check the derivation formula in the formula field  1006  for syntax errors. Syntax errors include inoperable combinations of mathematical symbols and failed logical expressions. The system may check all possible point values for points in the formula field to ensure the formula will not encounter any errors and/or will always output a value for the virtual point. In some embodiments, the system highlights particular operators in the formula field that caused a syntax error or suggests corrections. 
     The virtual point definition widget  1000  may also include a save button  1014 . The save button  1014  may be configured to only be selectable after the analytics system  604  has validated the syntax of the derivation formula in the formula field. The save button  1014  allows the user to save the derivation formula for a new virtual point and return to the meter configuration interface  900  shown in  FIG. 9 . The virtual point definition widget  1000  may also be used to edit derivation formulas for existing virtual points. 
     Referring now to  FIG. 11 , a building scorecard dashboard  1100  is shown, according to an exemplary embodiment. The building scorecard dashboard  1100  includes a hierarchical navigation list  1102  of facilities, buildings, building subsystems or subareas, meters, and points. Meters on the navigation list may include a status indictor  1104  configured to show whether that meter is online, offline, or virtual. Points listed under meter include both real points and virtual points. When a meter is selected on the navigation list, a meter visualization widget  1106  may be displayed on the building scorecard dashboard. The meter visualization widget  1106  may include a graphical representation of the data associated with all points under the meter, include real and virtual points. Time selection  1108  may be available in the upper right corner and can be switched easily between one week, one month, three months, six months, one year, and any custom range. The graphical display may then be adjusted to display data from the selected time range. A grid toggle  1110  may also be available to easily switch between the graphical display and a display of the meter data in a grid format. 
     The meter visualization widget  1106  presents data from a virtual point in the same way it presents data from real points. The building scorecard dashboard  1100  may also include displays of building and facility key performance indicators that include data roll-ups from all meters in the buildings or facilities. Virtual points are treated identically to real points in these roll-up calculations and in generating visualizations for the building scorecard dashboard. 
     Configuration of Exemplary Embodiments 
     The construction and arrangement of the systems and methods as shown in the various exemplary embodiments are illustrative only. Although only a few embodiments have been described in detail in this disclosure, many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.). For example, the position of elements can be reversed or otherwise varied and the nature or number of discrete elements or positions can be altered or varied. Accordingly, all such modifications are intended to be included within the scope of the present disclosure. The order or sequence of any process or method steps can be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes, and omissions can be made in the design, operating conditions and arrangement of the exemplary embodiments without departing from the scope of the present disclosure. 
     The present disclosure contemplates methods, systems and program products on any machine-readable media for accomplishing various operations. The embodiments of the present disclosure can be implemented using existing computer processors, or by a special purpose computer processor for an appropriate system, incorporated for this or another purpose, or by a hardwired system. Embodiments within the scope of the present disclosure include program products comprising machine-readable media for carrying or having machine-executable instructions or data structures stored thereon. Such machine-readable media can be any available media that can be accessed by a general purpose or special purpose computer or other machine with a processor. By way of example, such machine-readable media can comprise RAM, ROM, EPROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to carry or store desired program code in the form of machine-executable instructions or data structures and which can be accessed by a general purpose or special purpose computer or other machine with a processor. Combinations of the above are also included within the scope of machine-readable media. Machine-executable instructions include, for example, instructions and data which cause a general purpose computer, special purpose computer, or special purpose processing machines to perform a certain function or group of functions. 
     Although the figures show a specific order of method steps, the order of the steps may differ from what is depicted. Also two or more steps can be performed concurrently or with partial concurrence. Such variation will depend on the software and hardware systems chosen and on designer choice. All such variations are within the scope of the disclosure. Likewise, software implementations could be accomplished with standard programming techniques with rule based logic and other logic to accomplish the various connection steps, processing steps, comparison steps and decision steps.