LED Status

PROFIBUS® status		Device status		Status / cause
LED green H1	LED red H2	LED green H3	LED red H4
off	off	off	off	Power supply is missing
on	flashes			Possible errors: - No connection to the bus master, e.g. PROFIBUSâ is not operating - The PDP21/PDP22 has a slave address that is not configured in the bus master - Parameter length and slave address are correct but the I/O configuration of the slave does not meet the configuration sent by the bus master
flashes	on			The device parameters received from the bus master are formal incorrect, e.g. of other length
off	on			Connection to the bus master is interrupted longer than the timeout set by the bus master before interruption
on	off			Normal data exchange to the PROFIBUSâ DP master
		on	off	Normal data exchange to the terminal device
flashes	flashes	flashes	flashes	Plug is under self-test during power-up
		flashes	off	Plug is waiting for configuration data to be sent from the device (number of input/output bytes, number of parameter bytes, internal baud rate etc.) Note: If no data has been sent by the terminal device within 3 s, the plug switches to the parallel mode.
		off	flashes	Error: can be remedied, e.g. connection to the terminal device is broken
		off	on	Error: cannot be remedied, e.g. incorrect check sum in the Flash. Exchange the plug.