Modbus Exception Code - Delta DFS150-485 User Manual

Appendix

Modbus Exception Code

Code Name
01 ILLEGAL FUNCTION
02 ILLEGAL DATA ADDRESS
03 ILLEGAL DATA VALUE
07 ERROR CEHCKSUM
09 INVALID TRIGGER
A-18
Meaning
The function code is not supported
The data address received in the query is not an
allowable address.
For a controller with 10 registers, the PDU
addresses the first register is 0x8001, and the
last one as 800A. If a request is submitted with a
starting register address of 0x8007 and a
quantity of registers of 4, then the request will
successfully operate on registers 0x8007,
0x8008, 0x8009, 0x800A..
If a request is submitted with a starting address
of 0x8009 and a quantity of registers of 3, then
this request will fail with Exception Code 0x02
since it attempts to operate on registers 0x8009,
0x800A and 0x800B, and there is no register with
address 0x800B.
A value contained in the query data field is not an
allowable value. This indicates a fault in the
structure of the request, such as that the implied
length is in correct or the value outside the
expectation of the application program.
The checksum of request command is error.
If the trigger command is received in the startup
communication period or system is in the busy
period.
Refer Figure 6. Start-up communication to Scan
mode and Figure 14. Valid trigger to create a
valid trigger.
DFS150-485 2D Fixed Scanner User Guide