Sensor Type Guide
- Kimberly Onnen
The following is a breakdown of the different terms that can be found within the sensor type names and what they mean in our schema. These are broken down categorically by what the words describe, with a brief summary of each category. These categories are defined starting with the data types and expanding outward to all terms that can qualify and describe the data.
Data Type
These are terms that define the specific data relative to the control or monitoring system. They describe "how" we handle the data of the sensor types.
Command - A binary or analog output intended to cause a specific action in the controlled elements.
Max Command - An analog value intended to limit the maximum possible "Command" output.
Min Command - An analog value intended to limit the minimum possible "Command" output.
Command Enum - A multi-state command intended to cause one of a subset of specifically stated in the controlled entities.
Deadband - An analog value that defines a buffer between two mutually exclusive states.
Enable - A boolean value that is intended to indicate whether a controlled element will be allowed to become active.
Max Setpoint - An analog value intended to limit the maximum possible "setpoint".
Min Setpoint - An analog value intended to limit the minimum possible "setpoint".
Off Setpoint - An analog value intended to indicate at what sensed value a particular state will be turned off.
On Setpoint - An analog value intended to indicate at what sensed value a particular state will be turned on.
Value - An analog input or calculated value representative of a physical measurement. Is excluded from the actual sensor name.
Setpoint - An analog value that describes the desired value for a given "Reading" to which the system will drive some "Command".
Deviation - An analog value that represents the difference between a controlled value and its target setpoint.
Status - A boolean input that conveys the state a system, equipment, or component is currently in. It is typically associated with on/off.
Status Enum - An enumerated input that conveys the state a system, equipment, or component is currently in.
Text - A text value.
Limits
These terms describe limits that are placed on the system values.
High Limit - The maximum allowable value for a controlled value prior to some kind of fault or alarm.
Low Limit - The minimum allowable value for a controlled value prior to some kind of fault or alarm.
Max - The highest input value for a configured value.
Min - The lowest input value for a configured value.
Occupancy Status
These are terms that define the occupational and/or operational state of certain areas, equipment, and/or systems. It is the "when" of the physical aspects of the sensor types.
Occupied - The areas served are recognized as having occupancy. This often correlates to an active state with the highest level of control.
Unoccupied - The areas served are recognized as not having occupancy. This often correlates to an inactive state with the lowest or no level of control.
Standby - The areas served are recognized as temporarily not having occupancy. This often correlates to an active state, but with a less precise level of control than the occupied state.
Control Variable
These are terms that define the specific information being monitored or controlled. This is the "what" of the stored information for the sensor type.
Alarm - Indication of some kind of problem.
Capacity - The amount that something can or is producing.
CO - Carbon Monoxide gas level.
CO2 - Carbon dioxide gas level.
Communication - Where or not something is in active communication with a control or monitoring system.
Current - The current reading of an electrical system.
Dewpoint - The temperature at which water will condense from the air, Typically, calculated from relative humidity and dry bulb temperature.
Energy - The amount of energy being used, typically associated with a utility.
Enthalpy - The amount of total heat energy in a system. Typically, used for comparisons of outside and return air sources to make economizing decisions.
Flow - The rate at which some medium is moving.
Frequency - The rate of oscillation of an alternating current.
Horsepower - The horsepower of a motor.
Level - The level of some medium relative to a container.
Load - The calculated demand for some action. Typically, used in PID calculations for heating or cooling.
Methane - The measured concentration of methane in the air.
Mode - The state to which something operates. Typically, is described by heating or cooling as well as any number of other equipment or system-specific modes.
Motion Sensor - The detection of movement within a space.
Scheduled Occupancy - The state of whether a particular space is treated as occupied based upon a schedule.
Occupancy - The state of whether something is treated as having occupancy.
Occupancy Sensor - Whether occupancy is physically detected in a given space.
Open - The boolean state of whether something is open. Typically, related to a valve, damper, or other physical control component.
O2 - Oxygen levels in a gas.
PM2.5 - The concentration of particulate matter less than 2.5 micrograms. Used in indoor air quality.
Position - The physical analog position of something. Typically, related to a value, damper, or other component.
Power - The rate at which electrical energy is transferred by a circuit.
Power Factor - The ratio of real power absorbed by the load relative to the apparent power flowing in the circuit.
Pressure - The force applied perpendicular to the surface of an object per unit of area.
Relative Humidity - The amount of moisture in the air relative to how much moisture the air can hold at the given temperature and pressure.
Resistance - Opposition to the flow of electricity.
RPM - Revolutions per minute.
Run - Boolean state of operation.
Runtime - The accumulated time something has run.
Speed - The speed at which something operates. Typically, in % relative to a motor.
Starts - Hourly - The number of times an equipment or component has started per hour.
Starts - Daily - The number of times an equipment or component has started per day.
Starts - Total - The number of times an equipment or component has started of all detected instances.
Subcooling - The deficit of temperature of a liquid below its temperature of saturation.
Superheat - The excess of temperature of a vapor above its temperature of saturation.
Switch - A binary status selector.
Temperature - The dry bulb temperature without regard to humidity.
Time - The amount of time something will or has happened.
Total Dissolved Solids - Measurement of substances present in water loops. Typically, used relative to open water loops.
Total Volatile Organic Compounds (TVOC) - The concentration of TVOC in the air. Used in indoor air quality.
Usage - The quantity used of some kind of medium, Typically, a utility.
Voltage - The electric potential between two points.
Wet bulb - The wet bulb temperature of air. Typically, used to evaluate evaporative cooling functions.
Components
These terms describe the physical components that comprise the equipment and systems. These are typically serving some mechanical function. These add context to the "what" and "where" of the sensor types we define.
Coil - A coil used to transfer energy, Typically, in the form of heat.
Compressor - Compresses a medium, Typically, air or refrigerant.
Condenser - Describes the sensors relative to the condenser portion of a refrigerant cycle.
Damper - Controls the flow of air.
Economizer - Describes the sensors and states relative to the preferential use of outside air over return air to reduce energy usage.
Evaporator - Describes the sensors relative to the evaporator portion of a refrigerant cycle.
Door - Encloses a space. Can be used as a measure of usage.
Drain Pan - Collects moisture for a component or system, Typically, relevant to cooling applications where condensation or water flow may be present.
Fan - Causes air flow.
Filter - Cleans contaminants from a given medium.
Freezestat - A special sensor used to indicate a risk of frozen components. Typically, leads to a physical equipment shutdown when tripped as part of a safety circuit.
Heater - A component that heats a given medium.
Humidifier - Introduces humidity to a space to maintain appropriate levels.
Phase Monitor - Detects whether 3 phases of power are present for certain equipment that require it.
Pre-Filter - Filter before the main filter, Typically, used in outside source applications.
Pump - Causes the flow of a fluid medium, Typically, water.
Smoke Detector - Detects the presence of smoke.
Stage - The condition of a component that can have multiple stages. Typically, use in heating components.
Valve - Controls the flow of a fluid medium, Typically, water.
Wheel - A rotational component. Typically, we use in the context of heat recovery.
Medium
These terms describe the physical medium being measured and/or qualifying the types of components which we're detecting. These add context to the "what" of the sensor types we define.
Air - Both used in terms of the atmosphere of given spaces and a medium to transfer heat for HVAC purposes.
Compressed Air - Typically, used in older control systems and for certain mechanical applications.
Electric - Used in any electrical component as well as utilities both from a usage and control standpoint.
Fuel - Fuel sources that are Typically, measured by storage or usage.
Hot Gas - The refrigerant in the portion of the cycle where it had picked up heat at the evaporator and is in a gaseous form. Typically, used in naming sensors related to hot gas bypass.
Ice - Ice used Typically, in cooling storage.
Light - The level of light detected. Can be indoor or outdoor.
Natural Gas - Utility source, Typically, used in heating applications.
Oil - Typically, used in refrigeration cycles.
Product - Can be critical to certain retail and food service applications.
Refrigerant - The medium by which heat is transferred in refrigeration systems.
Steam - Typically, used in high temperature heating applications.
Water - Can be consumed as a utility or utilized as a means to transfer heat for heating and cooling systems.
Position
These are terms that describe the relative position of a particular component, medium, or sensor to the equipment or system under which it is modeled. It is the physical "where" of the sensor types.
Bypass - The part of a system or equipment that is meant to bypass some other element, usually relates to a valve or damper.
Return - The part of a system or equipment that is returning some medium from a served entity in a loop (usually a space or equipment).
Supply - The part of a system or equipment that is supplying some medium out to a served entity in a loop (usually a space or equipment).
Differential- The difference between supply and return or entering and leaving readings. Typically, used in defining pressure differentials in a water loop.
Mixed - The part of a system or equipment where two different medium sources are mixed. Typically, used for air within an AHU.
Entering - The medium that is coming into a component in a closed loop such as a refrigerant cycle.
Leaving - The medium that is leaving a component in a closed loop such as a refrigerant cycle.
Parallel - Typically, refers to the plenum air source to a parallel VAV box. This source runs "parallel" to the primary air source and is used as a source of heating.
Saturated - The refrigerant that is within a condenser or evaporator and changing its state.
Site - Anything relative to the site as a whole such as pressure or utility usage.
Space - Anything relative to a specific area within the site.
Outside - From outside the site, Typically, used to describe air.
Purpose
These are terms that define the physical purpose a particular component, medium, or sensor is used in our equipment or systems. It is the physical "why" of the sensor types.
Cool Down - Describes the sensors and states relative to a cool down function, allowing equipment or areas to cool down.
Cooling - Describes the sensors and states intended to cool a particular medium.
Daytime Warmup - Describes the sensors and states intended to warm spaces in a VAV system during normal operation.
Defrost - Describes the sensors and states intended to remove frost from a refrigeration coil.
Dehumidification - Describes the sensors and states intended to remove moisture from the air.
Design - Describes the sensors that are input according to design specifications. Usually a manual input.
Dual Temp - Describes the sensors relative to a coil that can provide either heating or cooling depending on mode.
Exhaust - Describes the sensors that remove some medium out of the system.
Expansion - Describes the sensors and states relative to expansion of some medium, Typically, refrigerant.
Free Cooling - Describes the sensors and states relative to the usage of sufficiently cool outside air instead of mechanical cooling.
Heat Recovery - Describes the sensors and states relative to the recovery of heat from exhaust to supply of a particular medium.
Heating - Describes the sensors and states intended to heat a particular medium.
Isolation - Describes the sensors and states relative to the isolation of a particular entity.
Makeup - Describes the sensors relative to recovery of a medium from an outside source, usually to balance that which is exhausted or used.
Mechanical Cooling - Describes the sensors and states relative to the usage of mechanical refrigeration as a means to cool.
Morning Warmup - Describes the sensors and states intended to warm spaces in a VAV system during initial startup.
Night Purge - Describes the sensors and states relative to the use of cool nighttime air to pre-cool a space prior to initial startup.
Optimal Start - Describes the sensors and states relative to the use of a system or equipment start prior to typical scheduling in order to meet a target condition by a target time.
Optimal Stop - Describes the sensors and states relative to the use of a system or equipment stop prior to typical scheduling in order to save energy.
Preheat - Describes the sensors and states relative to heating an air source, Typically, to prevent freezing.
Recirculation - Describes the sensors and states relative to a safety mechanism to recirculate a medium, Typically, to prevent freezing.
Reversing - Describes the sensors and states relative to the reversal of some system of flow, Typically, refrigerant in a heat pump system.
Safety - Describes sensors relative to something generally safety-related, Typically, like a safety switch in a circuit.
Terminal - Describes the sensors calculated at a terminal unit, Typically, as a function of demand at those units.
Sub-System
These are terms that describe whether the sensors may exist within a particular defined part of a system. This is independent of the system definitions themselves.
Primary - The first part of a system that supplies a medium to some secondary equipment or system.
Secondary - The part of a system that is itself supplied by a primary system and further conditions or controls the medium before serving it to the final supplied space or equipment.