Unitary | Pre-APOGEE | APOGEE | BACnet | PXC.A |
|---|---|---|---|---|
| ● | ● | ● | ● |
Syntax
PDL(area,totkw,target,g1s,g1e,sh1,...,g4s,g4e,sh4)
area | Meter area number. - Enter this number as an integer. |
totkw | Total amount of power consumed by the loads that are controlled by the PDL command. - The same virtual LAO point must be used for both the PDL totkw parameter and the kwtot parameter in the owning PDLDPG command. The value of this parameter is calculated by the PDL command. A power-consuming load is controlled by a PDL command if the following criteria are met: - The power-consuming load is defined in a PDLDAT command that is associated with a PDL command. - The load is currently in NONE or PDL priority. - The PDL command is traced and is enabled. - The PDLDPG command is enabled. - The PDLDAT command is enabled. |
target | Power consumption limit that is maintained by the PDL command. - The same virtual LAO point must be used for both the PDL target parameter and the target parameter in the corresponding PDLDPG command. The value of this parameter is calculated by the PDLDPG command. |
g1s | Start line for the group 1 load definition in the corresponding PDLDAT commands. This is the first group to shed when demand exceeds the setpoint. |
g1e | End line for the group 1 load definition. |
sh1 | Shedding sequence for group 1. - Valid values are 0 and 1. 0 = Fixed shedding 1 = Round robin shedding |
g4s | Start line for the group 4 load definition in the corresponding PDLDAT commands. This is the last group to shed when demand exceeds the setpoint. |
G4e | End line for the group 4 load definition. |
sh4 | Shedding sequence for group 4. - Valid values are 0 and 1. 0 = Fixed shedding 1 = Round robin shedding |
Use
Maintains a defined level of kilowatt use (or target) for a group of loads.
NOTE:
For a detailed explanation of Peak Demand Limiting (PDL), see Control Option Comparisons.
A single PDL command is responsible for the direct control of a group of PDLDAT commands in a load-handling automation station. The PDL command control includes:
- Maintaining a target kilowatt (kW) value by shedding and restoring loads. The target value is passed to the PDL command through an LAO point value from the PDLDPG command.
- Monitoring the total available kilowatts under its control. The PDL command determines which of the loads defined in the associated PDLDAT command is available for peak demand limiting control. The total kilowatts available to the PDL command are placed in an LAO point.
- Maintaining the timing as defined in the PDLDAT command for minon, minoff, and maxoff.
- Defining how each load under PDL control fits into one of four priority groups. This is accomplished by referring to the line numbers of the PDLDAT commands.
- Defining and controlling the sequence of shedding and restoring for each priority group.
- There are two types of shedding and restoring: fixed and round robin.
- Shedding begins at 90% of the setpoint.
Example
100 PDL(1,TOTKW1,TGT1,100,199,0,200,299,1,
300,399,0,400,499,0)
Notes
- PDL must control 10-20% of the building demand to be effective.
- When points are controlled by the PDL command, they are placed into PDL priority. Group 1 is shed first, while Group 4 is shed last.
- With APOGEE firmware, one meter can be defined in each program.
- With pre-APOGEE firmware, only one meter can be defined in an automation station.
- The PDL statement fails if more than four shedding groups are defined.
- Do one of the following if all four shedding groups are not used:
- With Firmware Revision 2.6/2.6.1 and later, no entry is required for unused groups.
- With Firmware Revision 2.5.2 and earlier, enter the integer 0 for the starting line, ending line, and shedding type for all the unused groups.