Siemens SIMATIC S7-1200

Using PID_3Step
5.2 PID_3Step V2
PID control
Function Manual, 03/2017, A5E35300227-AC
137
5.2.3
Simulating PID_3Step V2 with PLCSIM
Note
Simulation with PLCSIM
The simulation of PID_3Step V2.x with PLCSIM for CPU S7
-1200 is not supported.
PID_3Step V2.x can only be simulated for CPU S7
-1500 with PLCSIM.
For the simulation with PLCSIM, the time behavior of
the simulated PLC is not exactly
identical to that of a "real" PLC. The actual cycle clock of a cyclic interrupt OB can have
larger fluctuations with a simulated PLC than with "real" PLCs.
In the standard configuration, PID_3Step determines the time betwee
n calls automatically
and monitors them for fluctuations.
For a simulation of PID_3Step with PLCSIM, for example, a sampling time error ((ErrorBits =
DW#16#00000800) can therefore be detected.
This results in ongoing tuning being aborted.
The response in
automatic mode depends on the value of the ActivateRecoverMode tag.
To prevent this from happening, you should configure PID_3Step for simulation with PLCSIM
as follows:
•
CycleTime.EnEstimation = FALSE
•
CycleTime.EnMonitoring = FALSE
•
CycleTime.Value: Assign the cycle clock of the calling cyclic interrupt OB in seconds to
this tag.