Diagnosis of the multi-function I/Os

This chapter describes the diagnostic options for multi-function I/O communication. This is important, for example, if the 24 V power supply for the multi-function I/Os fails or the circuit breaker has triggered.

Status variable

The status variable state can be used for diagnostic purposes. In the normal state, the status variable takes the value 0x___8 (OP, Operational) and thus indicates that everything is error-free.

The following table shows which values the variables can assume:

If there is a power supply failure, the multi-function I/Os do not automatically go back into data exchange. To do this, the multi-function I/Os must be reset. A function block that can be used to reset the multi-function I/Os is the FB_CX70xx_ResetOnBoardIO function block.

Notice : If outputs are still set in the PLC, the outputs of the multi-function I/Os are immediately reactivated as soon as the multi-function I/Os are reset with the function block.

Other diagnostic variables

The diagnostic variables Diag and TxPDO State are currently not in use and are reserved for future use. The variable Input cycle counter, on the other hand, increments with each cycle and indicates the number of I/O cycles exchanged with the multi-function I/Os. As soon as the variable is no longer incremented, no more I/O cycles are exchanged with the multi-function I/Os.