Schneider Electric LUFP9 user manual Description of the error

5. Gateway Initialization and Diagnostics

The correct use of this status word by the DeviceNet master, to read a diagnostic generated by the gateway, goes through the following steps:

•Checking of (ABC_HS_SEND ≠ FB_HS_CONFIRM).

• Reading of the value of ABC_DU to determine whether all of the Modbus input data are up-to-date.

• Reading of the value of the “Periodicity of Modbus exchanges” bit to determine whether the periodicity of the Modbus communications has been maintained.

• Reading of the values of EC and ED to check for any error detected by the gateway on the Modbus network (see table below).

• Copying of the value of the ABC_HS_SEND bit to the FB_HS_CONFIRM bit.

This last step is essential because it allows the gateway to transmit a future diagnostic! Even if you do not wish to read the content of the gateway’s status word, it is preferable to automate this step in your DeviceNet master software.

The values of the EC and ED fields are described in the table below:

EC	Description of the error	ED	Notes
2#0000	Re-transmissions on the	Number of re-	Total number of re-transmissions carried out
	Modbus network	transmissions (1)	on the sub-network, for all slaves.
2#0001	A Modbus slave is missing	Address of the missing	—
		Modbus slave
2#0010	Several Modbus slaves	—	—
	are missing
2#0011	Excessive data in a	Address of the Modbus	This error occurs when the gateway receives too
	Modbus response	slave involved	much data in the response sent by one of its
			Modbus slaves.
2#0100	Unknown Modbus error	Address of the Modbus	—
		slave involved

(1) The re-transmission counter used to signal this error is not reset when the gateway generates this error code. If there are recurrent communication problems on the Modbus network, the gateway will generate this same diagnostic repeatedly, so as to tell the DeviceNet master the total number of re-transmissions carried out as often as possible. This counter is reset when its value exceeds its maximum value (counter modulo 256: 16#FF Æ 16#00).

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