RMA
Member
Does anybody know when exactly a Bit which you switch in a VAT table gets updated in the PLC? I would hope that as with the peripheral devices the update takes place outside the normal program cycle - but am I right in my assumption - anbody know for sure?
The thought occurred to me in connection with my FM352-5 problem because in my test program there is nothing else in OB1 other than the calls to the DEBUG and NORMAL FBs for the 3 FMs, so if the update actually takes place during the cycle execution, there's a 50% chance of it happening between the calls to the two FBs controlling one of the FMs allowing both to run at the same time (since the DEBUG FM is called first), which is BIG no-no!
The thought occurred to me in connection with my FM352-5 problem because in my test program there is nothing else in OB1 other than the calls to the DEBUG and NORMAL FBs for the 3 FMs, so if the update actually takes place during the cycle execution, there's a 50% chance of it happening between the calls to the two FBs controlling one of the FMs allowing both to run at the same time (since the DEBUG FM is called first), which is BIG no-no!