Function Block for PROFINET IO alarms handling
The PROFINET IO specification defines the Alarm handling of IO Devices. It is based on event handling. A IO Device will raise an Alarm event and the IO Controller must retrieve the alarm from the IO device. If an IO Device has several alarms pending then the IO Controller must fetch them one after the other.
The PROFINET IO Controller CJ1W-PNT21 has the ability to fetch alarms from a IO Device. Therefore a FINS command is implemented. But with a functionblock the handling is much easier.
The principle of operation is that the IO Device signals that has an alarm. The FB will then retrieve the alarm and put it in a FIFO. In this way the last alarms are available in the PLC. There is per device a FB needed.