Diagnostic LEDs for Modbus

The two upper LEDs describe the Modbus status

LED green	LED red	E/A RUN	Description	Help
off	off	no meaning	- communication loss - Watchdog time expired	- start communication new - Watchdog reset or new start
off	on or flashing	no meaning	- error in data transmission	this can be caused by: - Parity error - Check sum error - too many stop bits - wrong baud rate
on	off	an	- Module in operation	no error