Mitsubishi Electric MELSEC iQ-R Series User Manual page 93

When the D LINK LED turns off
When the D LINK LED turns off, check the following.
Check item
Is the control station operating normally?
Is the control station connected to the network?
Does the communication cable used conform to the standard?
Does the station-to-station distance meet the specifications?
Does the cabling condition (bending radius) meet the
specifications?
Is any communication cable disconnected?
Are the modules of other stations connected normal?
Are station numbers unique?
Are 65 or more normal stations connected?
Is the reserved station set for the control station?
Is the set station number greater than the number of connected
modules?
Does a stop error occur in the CPU module?
If the above action does not solve the problem, perform the self-diagnostics test to check for hardware failure. (Page 95
Self-diagnostics test)
When the L ERR LED turns on or turns on and off in an unstable condition
When the L ERR LED turns on or turns on and off in an unstable condition, check the following.
Check item
Are the communication cables used normally?
Are other stations connected to the RJ71LP21-25 normal?
If the above actions do not solve the problem, perform the following tests to check for an error.
• Troubleshooting for when communication is unstable ( Page 124 When communication is unstable)
Action
• Check if the control station (sub-control station) is performing data link using the
MELSECNET diagnostics.
Check if the control station (sub-control station) is performing data link using the
MELSECNET diagnostics.
Replace the communication cable with one conforming to the standard.
Set the station-to-station distance within range.
Refer to the manual for the communication cable, and correct the bending radius.
Replace the communication cable.
• Check if the modules on the other stations are performing data link using the
MELSECNET diagnostics.
• Check the operating status of the modules on the other stations. ( User's manual for
the module used)
Change the duplicated station number.
Change the connection of the normal stations to 64 stations or less.
Remove the reserved station specified in the control station setting.
Correct the station number so that it is within the number of connected modules.
Follow the instruction displayed on the window.
Action
• Check if the communication cable which conforms the standard is used.
• Check if the station-to-station distance is set within range.
• Check if the communication cables are not disconnected.
• Check if a connector is about to come loose.
Check if the other stations are performing data link using the MELSECNET diagnostics.
4 TROUBLESHOOTING
4.1 Checking with LED
4
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