Siemens SIMATIC S7-1200 - Page 639

Technology instructions
10.2 PID control
S7-1200 Programmable controller
System Manual, V4.2, 09/2016, A5E02486680-AK
639
"Mode" /
"State"
Name
Description
4 Manual mode In this mode, the PID controller scales, limits, and transfers the value of parameter “Man-
ualValue” to the outputs.
The PID controller assigns “ManualValue” in the scaling of the PID-algorithm
(like“PidOutputSum”), so its value decides if it is effective at the heating or cooling out-
puts.
You can reach this mode by setting “Mode” = 4 or “ManualEnable”= TRUE.
5 Substitute
output value
with error
monitoring
(Recover
mode)
You can activate this mode by setting "Mode" = 5. The mode is an automatic error reac-
tion of the controller if Automatic mode is active at the moment the error occurs:
• SetSubstituteOutput = FALSE (Last valid output value)
• SetSubstituteOutput = TRUE (Value stored in parameter "SubstituteOutput")
When PID_Temp is in “Automatic mode” and the “ActivateRecoverMode” parameter =
TRUE, PID_Temp changes to this
mode in the case of the following errors:
• “Invalid value at "Input_PER" parameter. Check for an error at the analog input (for
example, wire broken)." (ErrorBits = DW#16#0002)
• “Invalid value at "Input" parameter. Value is not a number.” (ErrorBits = DW#16#0200)
• “Calculation of output value failed. Check the PID parameters.” (ErrorBits =
DW#16#0400)
• “Invalid value at "Setpoint" parameter. Value is not a number.” (ErrorBits =
DW#16#1000)
If the error is no longer pending, PID_Temp will switch back to Automatic mode automati-
cally.