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12 Diagnostics
12.1 Preliminary Checks
93
FX
3U
-J1939 User's Manual
11
Exam
pl
e
Program
12
D
iagnostics
12.1
Preliminary Checks
Check the RUN, FROM/TO, Tx/Rx, ERROR and POWER LED status.
1. RUN LED
2. FROM/TO LED
3. Tx/Rx LED
4. ERROR LED
*1.
ERROR LED has two kinds of flicker states: single flash and blinking. This LED flickers as follows.
LED State
Description
OFF
FX
3U
-J1939 is in offline.
ON
FX
3U
-J1939 is in online.
LED State
Description
OFF
PLC is not accessing BFMs in FX
3U
-J1939.
ON
PLC is accessing BFMs in FX
3U
-J1939.
LED State
Description
OFF
FX
3U
-J1939 is not transmitting or receiving messages.
ON
FX
3U
-J1939 is transmitting or receiving messages.
LED State
Description
OFF
Normal operation (status)
SINGLE FLASH
*1
FX
3U
-J1939 is in error passive state.
At least one of the error counters of the module has reached or exceeded the warning level.
Check the following points in the network.
•
Check that the terminating resistors at both ends of the network are connected.
•
Check that all nodes have the same baud rate setting.
•
Check that all nodes have a unique Node ID setting.
•
Check that the CAN_H, CAN_L and CAN_GND wires are not broken.
•
Check that the CAN_H, CAN_L and CAN_GND are wired correctly.
•
Check that the CAN_SHLD is grounded.
•
Check that the CAN_SHLD is connected at all nodes.
•
Check that the CAN cable wires do not short circuit other CAN cable wires.
BLINKING
*1
General error has occurred.
Check the error status in BFM #29.
Refer to Section 12.2
ON
FX
3U
-J1939 is in BUS-OFF state, or program/CPU error occurs in PLC main unit.
The LED will always be ON if there is a BUS OFF error, a general error (BFM #29, bit 0), or the FROM/TO watchdog
is expired.
•
Check the error status in BFM #29.
Refer to Section 12.2
•
Check the ERROR LED of the PLC
For FX
3G
Series PLC, refer to FX
3G
Hardware Edition
For FX
3GC
Series PLC, refer to FX
3GC
Hardware Edition
For FX
3U
Series PLC, refer to FX
3U
Hardware Edition
For FX
3UC
Series PLC, refer to FX
3UC
Hardware Edition
For FX5U PLC, refer to MELSEC iQ-F FX5U User's Manual (Hardware)
For FX5UC PLC, refer to MELSEC iQ-F FX5UC User's Manual (Hardware)
•
Check the sequence program for FROM/TO watchdog.
For the FROM/TO watchdog, refer to Section 5.8
•
Check that the CAN_H, CAN_L and CAN_GND are wired correctly.