BERG UBN 309 Bedienungsanleitung Seite 58

Exception codes for MODBUS TCP are following described:
$01 ILLEGAL FUNCTION: the function code is unknown by the server.
$02 ILLEGAL DATA ADDRESS: the data address received in the query is not an allowable address for
the slave (i.e. the combination of register and transfer length is invalid).
$03 ILLEGAL DATA VALUE: a value contained in the query data field is not an allowable value for the slave.
$04 SERVER FAILURE: the server failed during the execution.
$05 ACKNOWLEDGE: the server accepted the server invocation but the service requires a relatively long
time to execute. The server therefore returns only an aknowledgement of the service invocation re-
ceipt.
$06 SERVER BUSY: the server was unable to accept the MB request PDU. The client application has
the responsability of deciding if and when re-sending the request.
$0A GATEWAY PATH UNAVAILABLE: the slave is not configured or cannot communicate.
$0B GATEWAY TARGET DEVICE FAILED TO RESPOND: the slave is not available in the network.
58 MODBUS rTU/ASCII, TCP