### Zone Setpoint with Demand and Learning Adaptive Optimal Start IMPORTANT This microblock has been retired from the EIKON® microblock menu as of v5.5 and the release of ZS Sensors. However, it is still supported in the EIKON® application, controllers, and the WebCTRL® application. For new applications, use the BACnet Setpoint microblock.
Microblock family | Control microblocks
Icon and symbol |
What it does | Calculates effective heating and cooling setpoints and zone thermographic color for single-zone equipment. Can relax setpoints to reduce electric demand. Uses an optimal start algorithm to adjust the zone setpoint before the zone is occupied, ensuring that the zone temperature is within the occupied setpoints by the time the zone is occupied. Adjusts (learns) zone heating and cooling capacities based on optimal start system performance. You can program a zone's occupied and unoccupied heating and cooling setpoints. The zone's effective setpoints may differ from its programmed occupied setpoints because of the optimal start algorithm or electric demand reduction levels. The microblock compares the zone temperature to the zone's effective setpoint to determine the zone thermographic color that represents the control program status. Other microblocks (such as the If Color = microblock) can use this color to perform additional control. A typical zone thermographic color scale may look like this:
Click for details below How it works Limitations Inputs and outputs Properties Programming example Tips and tricks
#### How it works Heating and Cooling setpoints The microblock outputs the effective zone heating and cooling setpoints. Unless adjusted by the optimal start algorithm or electric demand reduction levels, the effective setpoints equal the programmed occupied and unoccupied setpoints. When the OCC input is true (on), the microblock outputs the occupied cooling and heating setpoint values. When the OCC input is not true (off), the microblock outputs the unoccupied heating and cooling setpoint values. Optimal start When the zone is unoccupied, the microblock uses the outside air temperature from the OAT input and the design temperatures and capacities set in the microblock to estimate the time to warm or cool the zone from the unoccupied setpoints to the occupied setpoints. When the estimated time is less than the remaining unoccupied time indicated by the FOR input, the microblock outputs the programmed unoccupied setpoint values. When the estimated time to reach the occupied setpoints equals the remaining unoccupied time, the microblock transitions the effective setpoints to the occupied setpoints using a first-order curve that approximates system performance at full capacity. Heating capacity calculation during optimal start Cooling capacity calculation during optimal start Learning adaptive optimal start To minimize the energy required during optimal start, the learning adaptive optimal start algorithm evaluates the zone thermographic color at occupancy and adjusts the learned heating or cooling capacity for the next unoccupied period. If the zone temperature does not reach the setpoint by occupancy (the zone's thermographic color is not green at occupancy) the algorithm reduces the learned capacity by the adjustment value you defined for the zone's thermographic color at occupancy. During the next unoccupied period, optimal start begins sooner because the capacity is lower. If the zone temperature reaches the effective setpoint at any time during optimal start, the algorithm increases the learned heating or cooling capacity by the applicable green adjustment value regardless of the zone's color at occupancy. During the next unoccupied period, optimal start begins later because the capacity is higher. EXAMPLE A zone's heating capacity is 5° per hour. Its light blue learning adaptive adjustment value is 0.06. If at occupancy, the zone's thermographic color is light blue, the microblock uses a learned heating capacity of 4.94° (5° – .06°) per hour in its optimal start calculations for the next unoccupied period. This microblock calculates optimal start times more accurately and controls equipment more efficiently than microblocks without learning adaptive optimal start because it uses learned capacities in its calculations. Learned capacities are displayed on the Properties page and are available to other parts of the control program from the HCAP and CCAP outputs. NOTES The algorithm will not adjust learned heating and cooling capacities lower than 0.0625° per hour. If a user downloads new heating and cooling capacity values to the controller, the learned heating and cooling capacities change to the new values. If other properties from the control program are downloaded to the controller but the capacities do not change, the learned capacities are not affected. If a user downloads All Content to the controller, the learned heating and cooling capacities are reset to the microblock's heating and cooling capacities. To prevent learned capacities from being distorted during override periods, use the learning inhibit (LRNI) input to prevent learned capacities from being adjusted during override periods. When the LRNI input is true (on), optimal start operates normally but learned capacities are not adjusted for the next unoccupied period. Make sure that all other control sequences in the control program, including PID loops, are tuned and functioning properly to prevent improper setpoint adjustment. Electric demand reduction Electric rates vary with electricity usage. To keep your system's usage below the peak demand levels that incur extra charges, you can define 3 demand levels in your electric meter's control program. You can use these demand levels to relax zone occupied heating and cooling setpoints as needed throughout your system. Relaxing setpoints reduces equipment operation and reduces electric demand while minimizing the effects on occupant comfort. To use this electric demand reduction strategy in a zone, set up an Analog Network Input microblock to read the demand level (1, 2, or 3) from the electric meter's control program and connect the Analog Network Input microblock to this microblock's DEM input. When the electric meter's control program indicates a demand level of 1, this microblock relaxes occupied heating and cooling setpoints and all related color band thresholds by the Demand1 offsets you define. Similarly, a demand level of 2 relaxes setpoints by the Demand2 offset and a demand level of 3 relaxes setpoints by the Demand3 offset. By defining demand level offsets for each zone, the system can reduce electric demand with significant changes to the setpoints in non-critical zones and little or no change to the setpoints in critical zones. EXAMPLE A typical demand offset strategy and resulting effective setpoints and color thresholds Zone thermographic color The microblock compares the zone temperature from the ZONE input to the zone's effective setpoints and resulting color scale to determine the zone color output value. EXAMPLES Unoccupied If the unoccupied zone temperature (65°) is between the unoccupied heating (55°) and cooling (90°) setpoints and the zone is not in optimal start, the microblock sets the color output value to unoccupied gray. Occupied If the occupied zone temperature (79°) exceeds the occupied cooling setpoint (76°) by more than the yellow color band value (2°) but less than the yellow and orange color band values (2° + 2° = 4°), the microblock sets the color output value to orange. Optimal start If the zone temperature (60°) exceeds the effective heating setpoint (62°), the microblock sets the color output value to light blue. If the zone temperature (85°) exceeds the effective cooling setpoint (84°), the microblock sets the color output value to yellow. Demand level 1 If the occupied zone temperature (68°) exceeds the occupied heating setpoint minus the Demand1 offset (70° – 1° = 69°) by less than the light blue band value (2°), the microblock sets the color output value to light blue. Color Change Hysteresis The Color Change Hysteresis provides a difference between the temperature at which the zone color changes as the zone temperature departs from the acceptable range between the heating and cooling setpoints and the temperature at which the zone color changes back as the zone temperature returns to the acceptable range. EXAMPLE The following graph shows the zone color that results as the zone temperature departs from and returns to the acceptable range in a zone with the following settings: Color Change Hysteresis = 1° (applies as the temperature returns to the acceptable range) Occupied cooling setpoint = 76° Occupied heating setpoint = 70°
#### Limitations A control program can use only one Zone Setpoint microblock. Do not use a Set Color microblock or any Set Color If True microblocks in a control program with a Zone Setpoint microblock. This microblock is not a BACnet object, therefore you cannot directly expose its setpoints to BACnet.
#### Inputs and outputs Inputs
OAT Outside Air Temperature | Current outside air temperature (degrees).
OCC Occupied Schedule | True (on) when the zone is occupied. Not true (off) when the zone is unoccupied. Connect to a time clock microblock or to other logic that indicates the zone's occupancy status.
FOR Remaining Time | Minutes remaining until the zone's occupancy status changes. Connect to a time clock microblock or to other logic that indicates this time.
ZONE Zone Temperature | Current zone temperature (degrees).
DEM Demand Level | Current electric demand level (1–3). Connect to the Analog Network Input microblock that reads demand level from the electric meter's control program.
LRNI Learning Adaptive Inhibit | True (on) when learned heating and cooling capacities will not be adjusted by the learning adaptive optimal start algorithm. NOTE Optimal start is not affected by this input.
Outputs
Zone Color | Zone thermographic color based on ZONE input compared to effective setpoints.
Color |  | Status code | Condition indicated
--- | --- | --- | ---
| Red | 9 | Cooling alarm
| Orange | 8 | Maximum cooling
| Yellow | 7 | Moderate cooling
| Light green | 6 | Free cooling
| Green | 5 | No heating or cooling
| Light blue | 4 | Moderate heating
| Dark blue | 3 | Maximum heating
| Red | 2 | Heating alarm
| Gray | 1 | Unoccupied
The microblock outputs the zone color's status code (1–9) on its zone color wire.
HT Heating Setpoint | Zone's effective heating setpoint (degrees).
CL Cooling Setpoint | Zone's effective cooling setpoint (degrees).
HCAP Learned Heating Capacity | The learned heating capacity (degrees/hour) calculated by the learning adaptive optimal start algorithm. See Learning adaptive optimal start in "How it works" in this microblock's help.
CCAP Learned Cooling Capacity | The learned cooling capacity (degrees/hour) calculated by the learning adaptive optimal start algorithm. See Learning adaptive optimal start in "How it works" in this microblock's help.
#### Properties TIPS Alt+click any value in the WebCTRL® or Field Assistant interface to view property details, including its editing privilege and expression (location path) for use on graphics. You can right-click some properties in the EIKON® Property Editor and select Make editable or Make read-only to determine that property's functionality in your system.
Reference Name RefName | Use the default reference name unless you want a more descriptive name for graphics or network links. Limitations: lower case only limited to 40 characters cannot begin with a number must be unique within a control program
Editing Privilege (EIKON® application only) | Preset - Each microblock property has an appropriate privilege or role assigned to it. You can use Global Modify in the WebCTRL® interface to find out what the actual privilege is. CAUTION If you change the Editing Privilege from Preset, the privilege you select will be used for all properties of this microblock, which is not always desirable.
Setpoints
Unoccupied, Occupied, and Demand Level Setpoints | The desired occupied and unoccupied zone setpoints (degrees), the value of each occupied color band (degrees), and the offsets for electric demand levels 1, 2, and 3 (degrees). A color band's value determines the threshold at which the microblock changes the zone thermographic color as the zone temperature departs from setpoint. You can use the free cooling light green color band to enable economizer operation. If you are not using this feature, type`0` for this band's value. Demand level offsets determine how much to relax the zone's occupied setpoints and color band thresholds under each electric demand level. When the electric meter's control program indicates a demand level of 1, this microblock relaxes occupied heating and cooling setpoints and all related color band thresholds by the Demand1 offsets you define. Similarly, a demand level of 2 relaxes setpoints by the Demand2 offset and a demand level of 3 relaxes setpoints by the Demand3 offset. EXAMPLE A zone thermographic color scale with typical demand offsets and resulting effective setpoints and color thresholds
Color Change Hysteresis | The desired difference (degrees) between the temperature at which the zone color changes as the zone temperature departs from the acceptable range between the heating and cooling setpoints and the temperature at which the zone color changes back as the zone temperature returns to the acceptable range. If you are not using zone thermographic color for equipment control, type`0`. See Color Change Hysteresis in "How it works" in this microblock's help.
Design Properties
Heating Capacity | The rate (degrees/hour) at which the zone temperature changes if the outside air temperature is 65°F and the heating system runs at full capacity. Adjust after startup based on system optimal start performance.
Cooling Capacity | The rate (degrees/hour) at which the zone temperature changes if the outside air temperature is 65°F and the cooling system runs at full capacity. Adjust after startup based on system optimal start performance.
Heating Design Temperature | The geographically-based outside air temperature (degrees) at which the heating system must run constantly in order to maintain comfort. Available in ASHRAE publications and most design references.
Cooling Design Temperature | The geographically-based outside air temperature (degrees) at which the cooling system must run constantly in order to maintain comfort. Available in ASHRAE publications and most design references.
Property Page Text
Show Property Page Text | Check to show this microblock's value on the equipment's Properties page.
Property Page Text | You can edit the microblock description that appears on the Properties page. See "Editing Properties page text using special characters" and "Formatting a microblock property" in EIKON® Help.
Learning Adaptive
Color adjustment values | The amount by which the microblock adjusts the zone's learned heating or cooling capacity when the zone is this thermographic color at occupancy. See Learning adaptive optimal start in "How it works" in this microblock's help.
#### Programming example This zone control strategy inhibits learned heating and cooling capacity adjustments during unoccupied override periods.
#### Tips and tricks Optimal start Write the control logic for the unoccupied mode to activate heating if the zone color is light blue or cooling if the zone color is yellow. This will bring the zone temperature back into the desired range during optimal start. Color change hysteresis If you are using zone thermographic color for floorplan display, but not for control, set the Color Change Hysteresis to`0`. Using zone color and hysteresis for control can confuse end users because it can prevent the zone color from changing at the programmed setpoints. If you are controlling equipment based on zone thermographic color, set the hysteresis large enough to prevent the equipment from changing back and forth between two different states if the temperature oscillates near the setpoint. Free cooling – economizer enable If you are using zone thermographic color for control in small single-zone systems or unit ventilators, you can use the light green free cooling color band to enable economizer operation before you enable mechanical cooling. Otherwise, set the free cooling color band value to`0`. Accessing heating and cooling setpoints through BACnet Although you cannot access the microblock's heating and cooling setpoints directly using BACnet, you can attach BACnet Status microblocks to the microblock's HT and CL outputs to expose the setpoints as read-only BACnet values. Learning adaptive optimal start As a system ages, its heating and cooling capacities decrease. Loose fan belts, dirty filters, and other symptoms of age can be obscured by a system that uses learning adaptive optimal start. To learn the true capacity of your system and to prevent obscuring system problems that need to be addressed, use learning adaptive optimal start for the first year after a system is installed and commissioned. Then use the microblock's LRNI input to turn off learning and type the learned capacities from the HCAP and CCAP outputs into the microblock's Heating Capacity and Cooling Capacity properties.