SUNSTONE CDDP-A - Page 86

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SUNSTONE CDDP-A USERS GUIDE
Code Name Explanation
0x03 ILLEGAL DATA VALUE A value contained in the query data eld is not an allow-
able value for server. This indicates a fault in the structure
of the remainder of a complex request, such as that the
implied length is incorrect. It specically does NOT mean
that a data item submitted for storage in a register has a
value outside the expectation of the application program,
since the MODBUS protocol is unaware of the signi-
cance of any particular value of any particular register.
0x04 SERVER DEVICE FAILURE An unrecoverable error occurred while the server was at-
tempting to perform the requested action.
0x05 ACKNOWLEDGE Specialized use in conjunction with programming com-
mands. The server has accepted the request and is
processing it, but a long duration of time will be required
to do so. This response is returned to prevent a timeout
error from occurring in the client. The client can next
issue a Poll Program Complete message to determine if
processing is completed.
0x06 SERVER DEVICE BUSY Specialized use in conjunction with programming com-
mands. The server is engaged in processing a long–dura-
tion program command. The client should retransmit the
message later when the server is free.
0x08 MEMORY PARITY ERROR Specialized use in conjunction with function codes 20 and
21 and reference type 6, to indicate that the extended le
area failed to pass a consistency check. The server at-
tempted to read record le, but detected a parity error in
the memory. The client can retry the request, but service
may be required on the server device.
0x0A GATEWAY PATH UNAVAILABLE Specialized use in conjunction with gateways, indicates
that the gateway was unable to allocate an internal com-
munication path from the input port to the output port for
processing the request. Usually means that the gateway
is miscongured or overloaded.
0x0B GATEWAY TARGET DEVICE FAILED TO
RESPOND
Specialized use in conjunction with gateways, indicates
that no response was obtained from the target device.
Usually means that the device is not present on the net-
work.