Greetings,
I'm new at PLC programming, but good a logic - so I thought.
I've inherited a PLC system, which is presently operating in the field just fine - vintage 5 years old. I can't get the code to execute on my desktop using the Unity Pro V12.0 simulator. I've reduced the code to a bunch of test routines - which are failing.
- The main SFC cycles fine. Changing BOOL values changes the path.
- The SFC steps show as TRUE when the plc cycle passes through them.
- However, the Structured Text (ST) in the SFC step does not execute at all. IE: The 'Main_2A.x THEN' resolves as TRUE but does not enter the line below. The inherited PLC system uses this approach everywhere.
Thoughts?
I'm new at PLC programming, but good a logic - so I thought.
I've inherited a PLC system, which is presently operating in the field just fine - vintage 5 years old. I can't get the code to execute on my desktop using the Unity Pro V12.0 simulator. I've reduced the code to a bunch of test routines - which are failing.
- The main SFC cycles fine. Changing BOOL values changes the path.
- The SFC steps show as TRUE when the plc cycle passes through them.
- However, the Structured Text (ST) in the SFC step does not execute at all. IE: The 'Main_2A.x THEN' resolves as TRUE but does not enter the line below. The inherited PLC system uses this approach everywhere.
Thoughts?