Operands Of The Pid Function; Parameters Of The Pid Function Block - GE VersaMax PLC User Manual

14.1 Operands of the PID Function

Para-meter
Location of the PID reference array,
which contains user-configurable and
Address
internal parameters, described in the
(????)
section,
later in this chapter. Uses 40 words that
cannot be shared.
The control loop or process set point.
Set using process variable counts, the
PID function adjusts the output control
SP
variable so that the process variable
matches the set point (zero error).
Process Variable input from the process
PV
being controlled. Often a %AI input.
When energized to 1 (through a
contact), the PID function block is in
MAN
manual mode. If this input is 0, the PID
function block is in automatic mode.
If energized along with MAN, increases
UP the control variable by 1 CV count per
solution of the PID function.
If energized along with MAN, decreases
DN the control variable by 1 CV count per
solution of the PID function.
The control variable output to the
CV
process. Often a %AQ output.
274 GFK-1503E
For public disclosure

14.1.1 Parameters of the PID Function Block

Description
Reference Array Parameters
The PID function compares feedback from
a process variable (PV) with a desired
process set point (SP) and updates a
control variable (CV) based on the error.
The PID function uses PID loop gains and
other parameters stored in a 40-word
reference array of 16-bit integer words to
solve the PID algorithm at the desired time
interval.
Allowed Types Allowed Operands
R, L, P, W and
WORD
symbolic
INT, BOOL array of
All except S, SA,
length 16 or more
SB, and SC
All except S, SA,
INT, BOOL array of
SB, and SC, and
length 16 or more
constant
NA Flow
NA Flow
NA Flow
INT, BOOL array of
All except %S and
length 16 or more
constant
Optional
No
No
No
No
No
No
No
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