Process Control Instructions
118 Rockwell Automation Publication 1756-RM006K-EN-P - November 2018
Structured Text
Condition/State Action Taken
Prescan See Prescan in the Function Block table.
Normal Execution See Tag.EnableIn is true in the Function Block table.
Postscan See Postscan in the Function Block table.
Initial Mode Applied on Instruction First Scan
The following table shows the ending control based on the program request
inputs.
Control at Start of
First Scan
ProgOperReq ProgProgReq ProgValueReset FirstRun Control at End of First
Scan
Operator Control false true false na Program Control
na false na na Operator Control
Program Control true Na false false Operator Control
na Na true true Operator Control
false false false true Operator Control
false true false na Program Control
na Na true false Program Control
false false false false Program Control
The following table shows the ending control based on the Manual, Auto, and
Hold mode requests.
Control at
Start of First
Scan
Oper
Auto
Req
Oper
Man
Req
Prog
Auto
Req
Prog
Man
Req
Prog
Hold
Req
Man
Hold
AftInit
Prog
Value
Reset
First
Run
Control at End
of First Scan
Operator
Control
na na na na na false na false Operator Current
mode
na na na na na na na
Operator Manual
mode
na na na na na true na na
Program
Control
na na false false false false na false Program Current
mode
na na na na na false true false
na na true false false false false na Program Auto
mode
na na na true false false false na Program Manual
mode
na na na na true false false na Program Hold
mode
na na na na na true na na