I have a task to convert S5 program to S7 program. In S5 program there are many OBs but one of them is OB2. In manual it says that it is used for hardware interrupts and for that it uses input byte IB0. In S5 configuration there is no interrupt card installed. On byte IB0 some error signals are connected (NOT-AUS, phase presence, PLC error, itd.) but I believe that they can not make interrupt because this is not interrupt card!!!
Is it possible that OB2 block is called on some other way in S5 program?
Thanks in advance,