Siemens Simatic S7-1500

Using PID_3Step
5.3 PID_3Step V1
PID control
Function Manual, 03/2017, A5E35300227-AC
147
5.3.1.4
Advanced settings V1
Actual value monitoring V1
Configure a warning high and low limit for the process value in the "Process value
monitoring" configuration window. If one of the warning limits is exceeded or undershot
during operation, a warning will be displayed at the PID_3Step instruction:
● At the InputWarning_H output parameter if the warning high limit has been exceeded
● At the InputWarning_L output parameter if the warning low limit has been undershot
The warning limits must be within the process value high and low limits.
The process value high and low limits will be used if you do not enter values.
Example
Process value high limit = 98° C; warning high limit = 90° C
Warning low limit = 10° C; process value low limit = 0° C
PID_3Step will respond as follows:
Process value
InputWarning_H
InputWarning_L
Operating mode
> 98° C
TRUE
FALSE
Inactive
≤ 98° C and > 90° C
TRUE
FALSE
Automatic mode
≤ 90° C and ≥ 10° C
FALSE
FALSE
Automatic mode
< 10° C and ≥ 0° C
FALSE
TRUE
Automatic mode
< 0° C
FALSE
TRUE
Inactive
PID parameters V1
The PID parameters are displayed in the "PID Parameters" configuration window. The PID
parameters will be adapted to your controlled system during controller tuning. You do not
need to enter the PID parameters manually.
The PID algorithm operates according to the following equation:
Symbol
Description
Δy
Output value of the PID algorithm
K
p
Proportional gain
s
Laplace operator
b
Proportional action weighting
w
Setpoint
x
Process value