User Guide

Table Of Contents
Command Syntax
Siemens Building Technologies, Inc. 3-31
DCR (Duty cycle routine)
Unitary pre-APOGEE APOGEE BACnet
Syntax
DCR(pt1,temp1,high1,low1,...,pt4,temp4,high4,low4)
pt1
through
pt4
Point names of the output points to be duty cycled.
This parameter can be an LDO, logical, physical, or
virtual point type.
temp1
through
temp4
Point names of the space temperature points.
high1
through
high4
High temperature limits of the space points.
This parameter can be a decimal, integer, point
name, or local variable.
low1
through
low4
Low temperature limits of the space points.
This parameter can be a decimal, integer, point
name, or local variable.
Use
Duty cycles an output point to keep a corresponding temperature
within the low and high values of a dead band.
Makes an ON/OFF decision every 5 minutes according to the
value of the parameters.
The output point is commanded ON when the temperature
point value is above the high limit or below the low limit.
The output point is commanded OFF when the temperature
point value is within the range of the high and low limits.
For each point, a space temperature, high temperature, and low
temperature parameter must be defined.
A maximum of 4 points can be controlled with one DCR
command.
APOGEE PPCL User’s Manual
3-32 Siemens Building Technologies, Inc.
Example
200 C THIS COMMAND WILL TURN ON IF
210 C SFAN'S VALUE FALLS BELOW 68 OR
220 C RISES ABOVE 78. THE POINT SFAN01
230 C WILL REMAIN ON/OFF FOR AT LEAST 5
240 C MINUTES ON EACH CYCLE.
250 DCR(SFAN01,RM109,78.0,68.0)
Notes
The DCR command has a priority of NONE. Therefore, the PPCL
program must be structured with IF/THEN/ELSE commands to
prevent conflicts between DCR and other commands with the same
priority.
See also
DC