Access via a second client

The EK9000 can also be addressed via a further client. This can access the coupler for reading. However, a write procedure is rejected and acknowledged with a Modbus error as long as the first client is still triggering the watchdog.

If the first client fails, the second client takes over after half the watchdog time and can write the outputs itself after half the watchdog time. If the watchdog time is set accordingly high, this can take place virtually non-reactively, i.e. the set outputs remain set. If the first client becomes active again, it then receives a Modbus error message when writing.

Function The manufacturer of the application is solely responsible for the use and method of this type of communication.

When this method doesn't take effect  The first client's application is frozen, but Modbus telegrams are still being sent. In this case the second Modbus client would have no chance to take over the EK9000 because Modbus telegrams are still being sent.