User Guide

Table Of Contents
Control Option Comparisons—Start/Stop Time Optimization (SSTO)
Siemens Building Technologies, Inc. 2-17
Heating Season—Optimum Stop Time
If the indoor temperature is less than the desired temperature, then the
optimum stop time is LE:
Where:
LE = Latest end time from SSTO command.
If the indoor temperature is greater than or equal to the desired
temperature, then the optimum stop time is:
OE + ((25 * HR * d) / f) + AE
Where:
OE = Occupancy end time from SSTO command.
HR = Heating retention coefficient (hcoef2) from SSTOCO
command.
d = Indoor temperature minus the desired temperature.
f = Outdoor temperature minus the desired temperature.
AE = Adjust end time from SSTO command.
APOGEE PPCL User’s Manual
2-18 Siemens Building Technologies, Inc.
Cooling Mode at Occupancy Begin
If the indoor temperature is greater than the desired temperature plus
one degree, then:
AB = AB - CA
Where:
AB = Adjust begin time from SSTO command.
CA = Cooling auto-tune coefficient (ccoef4) from SSTOCO
command.
If the indoor temperature is less than the desired temperature minus one
degree, then:
AB = AB + CA
Where:
AB = Adjust begin time from SSTO command.
CA = Cooling auto-tune coefficient (ccoef4) from SSTOCO
command.