Troubleshooting; Verification Upon Problem Occurrence - Mitsubishi MELSEC-Q Series User Manual

13 TROUBLESHOOTING

13 TROUBLESHOOTING
This chapter describes the details of the problems that may occur in the CC-Link
System, and lists the check items and procedures for each of the possible problems.

13.1 Verification upon Problem Occurrence

The following lists the details of the check items and procedures for each problem
occurrence.
Description of problem
Unable to perform data link for the entire system.
Unable to receive input from a remote I/O station.
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Check item
Are there any disconnected cables?
Are terminal resistors connected to the terminal
stations located at each end of the CC-Link system?
Are correct terminal resistors connected?
Has an error occurred at the master station's PLC
CPU?
Are the CC-Link parameters set in the PLC CPU of
the master station?
Does the sequence scan time exceed the tolerance
for each transmission rate when using the
synchronous mode?
10 Mbps : 50 ms
5 Mbps : 50 ms
2.5 Mbps : 100 ms
625 kbps : 400 ms
156 kbps : 800 ms
Has an error occurred at the master station?
Is the corresponding remote I/O station performing
data link?
Is data read from the correct address of remote
input RX (buffer memory)?
Is the correct master station parameter information
area being used (CPU built-in parameters, default
parameters)?
Is the corresponding remote I/O station number
recognized by the master station?
MELSEC-Q
Check procedure
• Check the cable connection visually or with a line
test.
• Check the line status (SW0090).
Connect the supplied terminal resistors to the
terminal stations located at each end of the CC-Link
system.
Connect the appropriate terminal resistors that
match the cable type used for the terminal stations
located at each end of the CC-Link system. (See
Section 7.5.)
Check the error code of the PLC CPU and take
corrective action.
Check the contents of the parameters for the PLC
CPU of the master station.
Switch to the asynchronous mode, or reduce the
transmission rate.
• Check the host parameter status (SW0068).
• Check the switch setting status (SW006A).
• Check the Loading status (SW0069).
• Check to see if the "ERR." LED on the master
station is flashing. (See Section 13.2.)
• Check the LED display on the corresponding
remote I/O station.
• Check the other station data link status of the
master station. (SW0080 to SW0083)
• Check the sequence program.
• Check the automatic refresh parameter setting.
Check parameter information (SW0067).
• Check the parameters.
• Check the total number of stations (SW0070).
• Check the max. communication station number
(SW0071).
• Check the number of connected modules
(SW0072).
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