Siemens S7-1200 System Manual page 424

Technology instructions
9.2 PID control
Parameter and type
InputWarning_L OUT
State OUT
Error OUT
ErrorBits OUT
You can use the outputs of the Output, Output_PER, and Output_PWM parameters in parallel.
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Data type Description
Bool If InputWarning_L = TRUE, the process value has reached or fallen
below the warning low limit. (Default value: FALSE)
Int Current operating mode of the PID controller. (Default value: 0)
You can change the operating mode using the Mode input parameter
and a rising edge at ModeActivate:
State = 0: Inactive
•
State = 1: Pre-tuning
•
State = 2: Manual fine tuning
•
State = 3: Automatic mode
•
State = 4: Manual mode
•
State = 5: Substitute output value with error monitoring
•
Bool If Error = TRUE, at least one error message is pending in this cycle.
(Default value: FALSE)
Note: The Error parameter in V1.x PID was the ErrorBits field that
contained the error codes. It is now a Boolean flag indicating that an
error has occurred.
DWord The PID_Compact instruction ErrorBits parameters table (Page 426)
defines the error messages that are pending. (Default value:
DW#16#0000 (no error)). ErrorBits is retentive and is reset upon a
rising edge at Reset or ErrorAck.
Note: In V1.x, the ErrorBits parameter was defined as the Error
parameter and did not exist.
S7-1200 Programmable controller
System Manual, 03/2014, A5E02486680-AG