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MELSEC-Q 
8  TROUBLESHOOTING 
Item  Description 
CRC  During received data code check errors: Illuminated 
1)-a: Forward loop side, 1)-b: Reverse loop side 
OVER  During delayed received data processing errors: Illuminated 
1)-a: Forward loop side, 1)-b: Reverse loop side 
AB.IF.  When errors are triggered owing to values other than the stipulated "1" are received 
consecutively, and when errors are triggered owing to the length of the received data being too 
short: Illuminated 
1)-a: Forward loop side, 1)-b: Reverse loop side 
TIME  When errors are triggered owing to the data link monitoring timer being activated: Illuminated 
1)-a: Forward loop side, 1)-b: Reverse loop side 
DATA  When errors are triggered owing to abnormal data exceeding 2kbytes has been received: 
Illuminated 
1)-a: Forward loop side, 1)-b: Reverse loop side 
UNDER  When errors are triggered owing to the internal processing of transmission data not being 
completed within the specified period of time: Illuminated 
1)-a: Forward loop side, 1)-b: Reverse loop side 
LOOP  When errors are triggered owing abnormalities on the loop: Illuminated 
1)-a: Forward loop side, 1)-b: Reverse loop side 
 
2)  H/W switch information 
Displays the switch information for the network module. 
 
2)-a: Displays the switch settings for the H/W mounted on the network 
module. 
 
Item  Description 
STx10  Position 10 of the station number setting switch 
STx1  Position 1 of the station number setting switch 
MODE  Mode setting switch 
 
2)-b: Displays the switch information actually set up on the network module. 
 
Item  Description  Display range 
NETNO.  Network number setting  0 to 239 
GRPNO.  Group number setting  0 to 9 
STNO.  Station number setting  1 to 64 
MODE  Operation mode setting  0: On-line 
7: Self loop-back test 
8: Internal self loop-back test 
9: Hardware test 
BAUD  Communication speed 
Optical loop  Coaxial bus  Twisted bus 
0: 10 Mbps 
1: 25 Mbps 
0: 10 Mbps  0: 156Kbps 
1: 312Kbps 
2: 625Kbps 
3: 1.25Mbps 
4: 2.5Mbps 
5: 5Mbps 
6: 10Mbps 
CONFIG  Station type, controlled station operations 
during recovery, transmission mode settings 
 
 
 
 
 
b15
b8
b7 b0
All "0"
b5
Empty
Controlled station 
operations
 0: Switched
 1: Not switched
Transmission mode
 0: On-line mode (start)
 1: Debug mode (stop)
Station type
 0: Normal station
 1: Controlled station