User`s manual

107
FX3U Series Programmable Controllers
User’s Manual - MODBUS Serial Communication Edition
12 Troubleshooting
12.6 MODBUS Error Code List
11
Practical Program Examples
12
Troubleshooting
0204
Bit-level Error
Parity, overrun (rx register) or framing error
Master
/ Slave
See above
Check
Communication
Format data register
D8400 or D8420 for
errors.
0205
CRC/LRC Error
Message CRC/LRC is invalid, or message
length ≤ 3 characters (RTU) or ≤ 8 characters
(ASCII)
Master
/ Slave
See above
Check the
Communication
Format, Turn Around
Delay, and Message
to Message Delay
data registers for
errors;
D8400 and
D8410-D8411, or
D8420 and
D8430-D8431.
0206
Bus Character Overrun
- When more than 256 bytes are
received in RTU mode (more than 513
bytes in ASCII mode)
- (Slave only) When another telegram is
received while the former request is still
in process
Master
/ Slave
See above
Check the Turn
Around Delay and
Message to Message
Delay data registers
for errors;
D8410-D8411, or
D8430-D8431.
Also verify that the
serial port settings
are correct.
0207
Data Length Mismatch
The received data does not match the byte
count value within the telegram, or the device
count exceeds the maximum limit for the
command.
Master
/ Slave
See above
Verify that the Slave
is using MODBUS
Serial
Communication and
that the correct
command was
received.
Also verify that the
device count of the
command is within
the limits of the Slave
and Master.
Protocol error may
occur if you don’t
program correctly.
0208
Unconvertible Character Error
When in ASCII mode a byte code can not be
converted
(any character except '0'-'9' and 'A'-'F' ('a'-'f'))
Master
/ Slave
See above
See Corrective
Actions for Error
Code 207.
0209
Unsupported Command Code Error
The requested Command Code is invalid or
not supported
Slave See above
Verify that the
command used is
within the Master and
Slave specifications.
MODBUS
Error
Code
Error Name and Details
Master
/ Slave
Related Devices:(M & D) Corrective Action