IDEC FT1A-B12RA, User Manual

Page: 362 / 393

14: T
ROUBLESHOOTING
14-22 S
MART
AXIS P
RO
/L
ITE
U
SER
'
S
M
ANUAL
FT9Y-B1378
Troubleshooting Diagram 15
*1 See "Communication Error Data" on page 11-3.
Confirm slave settings again.
Make sure that the slave is compatible
with the function code.
Make sure that the slave number and
communication settings are correct.
Are communication
parameters equal at master and
slave?
Modbus RTU master
communication does not work.
YES
NO
YES
NO
YES
Confirm communication settings using
WindLDR (see "Programming Modbus
Master Using WindLDR" on page 11-4.)
Confirm the slave number (high-order
byte) and error code (low-order byte)
*1
.
Make sure that slave address settings are
correct.
Turn on the request execution device.
YES
Is it clear which
request has an error?
NO
See the request table to find which request
has an error and what error occurred (see
"Communication Error Data of Each
Request" on page 11-3).
YES
01h (function error)?
NO
02h (access destination error)?
NO
YES
03h (device
quantity error, 1-bit write
data error)?
NO
YES
16h (timeout error)?
NO
NO
Make sure of the valid slave address
range and master settings.
YES
Data size and actual data may not
match. Make sure that slave settings
and hardware are correct (without noise
and failure).
When the communication
error status is configured, is the error
information stored?
*1
Set to use a request
execution device and the device
is not turned on.