For some reason the internal variables were not updating when the corresponding external variable to a DFB was being changed. It appears the function block is not being scanned every cycle, or at least the data is not updating every cycle. I have an M580, Unity pro 13.1. Anyone have any suggestions???
Are you sure that you DFB is executed at each cycle ? you can check by setting a watch point on the DFB and look at the counter, if it remains to the same value that means the DFB is not executed. When the DFB is executed all the variables connected to it are exchanged. The EN pin on the DFB may be also the cause, if it is set to 0 the DFB is not executed. Another possibility is that the variables change their state after the DFB execution, so in the program animation, you see the last state. The watch point removes this ambiguity. Here an example of a watch point on a FBD section. Select the DFB and set the watch point on it.
The state of the variables are also refreshed when the DFB is executed, so you can see the real state of your data.