Define variable with READ/WRITE access
I am working on a User Function Block.
I want to programm UFB for motor control. The motor is controlled by Operator Command (from Faceplate) or by a sequence of Chart.
I want to define 2 variables:
- 1 variable for Automatic mode
- 1 variable for Automatic Command.
To avoid change of command in case of transition (from Free mode to Automatic Mode or from Automatic Mode to Free mode), i want to usein my UFB variable with READ and WRITE Access. This variable will be write in my UFB program (in case of free mode only) and also with the sequence (in case of automatic mode).
What kind of variable to use ? VAR IN does not allow to write.
VAR_DPS are only local.