Siemens SIMATIC S7 System Manual page 339

Table 9- 19 Sample configuration settings for the PID_3Step instruction
Settings
Basic Controller type
Invert the control logic
Enable last mode after
CPU restart
Input
Output
Feedback
Process Scales both the range and the limits for the process value. If the process value goes below the low limit or
value above the high limit, the PID loop goes to inactive mode and sets the output value to 0.
To use Input_PER, you must scale the analog process value (input value).
Actuator Motor transition
time
Minimum ON time
Minimum OFF
time
Error behavior
Scale Position
Feedback
1
"Scale Position Feedback" is editable only if you enabled "Feedback" in the "Basic" settings.
1
S7-1200 Programmable controller
System Manual, 11/2011, A5E02486680-05
Description
Selects the engineering units.
Allows selection of a reverse-acting PID loop.
If not selected, the PID loop is in direct-acting mode, and the output of PID loop

increases if the input value < setpoint).
If selected, the output of the PID loop increases if the input value > setpoint.

Restarts the PID loop after it is reset or if an input limit has been exceeded and
returned to the valid range.
Selects either the Input parameter or the Input_PER parameter (for analog) for the
process value. Input_PER can come directly from an analog input module.
Selects either to use the digital outputs (Output_UP and Output_DN) or to use the
analog output (Output_PER) for the output value.
Selects the type of device status returned to the PID loop:
No feedback (default)

Feedback

Feedback_PER

Sets the time from open to close for the valve. (Locate this value on the data sheet or
the faceplate of the valve.)
Sets the minimum movement time for the valve. (Locate this value on the data sheet or
the faceplate of the valve.)
Sets the minimum pause time for the valve. (Locate this value on the data sheet or the
faceplate of the valve.)
Defines the behavior of the valve when an error is detected or when the PID loop is
reset. If you select to use a substitute position, enter the "Safety position". For analog
feedback or analog output, select a value between the upper or lower limit for the
output. For digital outputs, you can choose only 0% (off) or 100% (on).
"High stop" and "Lower limit stop" define the maximum positive position (full-open)

and the maximum negative position (full-closed). "High stop" must be greater than
"Lower limit stop".
"High limit process value" and "Low limit process value" define the upper and lower

positions of the valve during tuning and automatic mode.
"FeedbackPER" ("Low" and "High") defines the analog feedback of the valve

position. "FeedbackPER High" must be greater than "FeedbackPER Low".
102BTechnology instructions
9.2 PID control
339