Instruction manual

IMCB14-E1
35
8. TROUBLESHOOTING
This section lists some basic causes and solutions for Modbus communication problems.
If you can not find a solution, contact your nearest RKC sales office or agent for additional
information about replacement or repair.
Symptom Probable cause Solution
No response The controller power is not turned on Turn on the power
There communication cable is improperly
connected
Confirm the connection method
Breakage in the communication cable Replace the cable
Detachment of the communication cable Confirm the connection condition
Problems with the connectors or contacts Check and replace the wiring in the
connector
The communication speed or bit structure
settings are different
Confirm each setting
The address specification is different Confirm the address numbers
A transmission error (overrun error, framing
error, parity error or CRC-16 error) is found in
the query message
Re-transmit after time-out occurs or
verify communication program
The time interval between adjacent data in the
query message is too long, exceeding 24 bit's
time
Instrument failure
Replace instrument or return for
repair
Continued on the next page.
z
To prevent electric shock or instrument failure, always turn off the system
power before replacing the instrument.
z
To prevent electric shock or instrument failure, always turn off the power
before mounting or removing the instrument.
z
To prevent electric shock or instrument failure, do not turn on the power until
all the wiring is completed.
z
To prevent electric shock or instrument failure, do not touch the inside of the
instrument.
z
All wiring must be performed by authorized personnel with electrical
experience in this type of work.
WARNING
!