YASKAWA GPD 315/V7 - Chapter 5 Parameter Tables

GPD315 Modbus RTU Technical Manual TM 4325
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16
Write Registers Fault Response
Table 4-10 Write Registers Fault Response Message
Slave Address 01h
Function Code 90h
Error Code 02h
Lower CDh
CRC-16
Upper C1h
The fault response message contains the same slave address as the command message,
indicating to the master which slave is responding.
The function code of a fault response message is actually a value of 80h plus the original
function code of 10h. This indicates to the master that the message is a fault response message,
instead of a normal response message.
The error code indicates where the error occurred in the command message. The value of 2h in
the error code field of this fault response message, indicates that the command message
requested data to be written to an invalid register. A complete listing of the error codes is shown
in Chapter 6, Troubleshooting and Error Codes.
A CRC-16 value is generated from a calculation using the values of the address, function code,
and error code sections of the message. The procedure for calculating a CRC-16 value is
described at the end of this chapter. When the master receives the fault response message it
calculates a CRC-16 value and compares it to the one in the CRC-16 field of the response
message. If these two CRC-16 values are the same the master has received the proper
response message.