User Guide

Command Syntax
Siemens Building Technologies, Inc. 3-15
Either the ADAPTM or ADAPTS control statement can be
implemented as a one-line replacement for an existing LOOP
statement in PPCL.
ADAPTM is specifically designed for supply air temperature control
in which two or three output devices are controlled in sequence
without overlap.
The output of ADAPTM is direct acting–it rises in value as the
process variable rises. To control multiple outputs, ADAPTM must be
connected to TABLE statements with parameters set such that the
mixed air damper output and the cooling coil output have direct
action, and the heating coil output has reverse action.
To be able to control, adaptive control requires that the loop be:
• Controllable–this means that the sensor is in the right range and
the output is sufficient to bring the process variable to setpoint.
• Open-loop Stable–this means that the process can achieve a
steady state for every position of the final output device. (All AHU
loops are open-loop stable.)
• Direct or Reverse Acting–this means the process is either
always direct or always reverse acting. That is, the process does
not change its action (direction or sign) within the control range.
• Modulating–this refers to the loop’s output device, such as a
cooling coil with a modulating water valve. For example, DX
cooling or step controlled electric heat, cannot be controlled by
the ADAPTM or ADAPTS statements in PPCL.
• Not Excessive in Dead Time–this means that the total delay in
the sensor and actuator signals should not exceed two times the
time constant of the process.
NOTE: The Soft Controller does not support adaptive control
technology.
See also
ADAPTS, LOOP
APOGEE PPCL User’s Manual
3-16 Siemens Building Technologies, Inc.
ADAPTS (Adaptive control, single)
Unitary pre-APOGEE APOGEE BACnet
 
Syntax
ADAPTS(pv,cv,sp,st,kc,tc,ra,llpv,hlpv,llcv,hlcv,edb,npv,err)
pv Process variable that is being controlled.
• This parameter can be a point name or local variable. It
is usually an LAI point, but can be an LAO point–a
calculated point representing a temperature, flow rate,
air velocity, etc.
• This value should always be between llpv and hlpv.
cv Controlled variable (loop output).
• This parameter can be a point name or local variable. It
is usually an LAO point that represents an actuator
signal.
sp Setpoint for the loop against which the process variable is
compared.
• This parameter can be entered as a point name, local
variable name, or decimal number.
• This value must be between llpv and hlpv, and should
represent the same engineering units as the process
variable.
st Sample time (in seconds). This is the time, in seconds, between
two successive starts of execution of the ADAPTS algorithm. It
is also the time interval between two samples of data by
ADAPTS.
• This parameter can be an integer, point name, or local
variable name.
• The minimum sample time allowed is 1 second.
• The Sample Time must be less than or equal to one-
third of the Time Constant. That is,
tcst
3
1
≤
Where:
st is the Sample Time, and
tc is the Time Constant.