User`s manual

110
FX3U Series Programmable Controllers
User’s Manual - MODBUS Serial Communication Edition
12 Troubleshooting
12.6 MODBUS Error Code List
1. Exception codes supported by FX3U MODBUS Slave
The following table outlines the exception codes supported by the MODBUS slave device.
Exception
code
Exception name Details
01H Illegal Function The requested function (code) is unsupported by the slave
02H Illegal device address
The requested device address or device address + device count
exceeds the supported range of this slave
03H Illegal data value
One of the fields within the request exceeds the allowed value (e.g.
the implied length, the device count)
04H Slave device failure
An unrecoverable error occurred while the slave was processing the
request