Mitsubishi Electric MELSEC Q Series Reference Manual page 315

(5) Detection of cable disconnection and cable insertion errors
Cable disconnections and cable insertion errors are checked through the CC IE Control diagnostics, but they also
can be checked with link special relay (SB) and link special register (SW). (
(a) Checking for cable disconnection and cable insertion errors
1.
When there is a cable disconnection or cable insertion error, loopback occurs.
When loopback occurs, loopback status (SB0065) is turned ON.
Also, loopback information can be checked in Loopback information (SB0065).
2.
Stations where loopback has occurred can be checked with the following link special relay (SW).
• IN-side loopback station No. (SW0070)
• OUT-side loopback station No. (SW0080)
3.
The cause of loopback can be checked with the following link special register (SW).
• IN-side loopback factor (SW0071)
• OUT-side loopback factor (SW0081)
4.
When the cause of loopback is a cable insertion error, the station No. of the station which has the
cable insertion error is stored in the following link special register (SW). (The station No. to be
stored is the one for connection target where the cable is connected.)
• OUT-side mis-cabling station No. (SW0072)
• IN-side mis-cabling station No. (SW0082)
5.
The details of the cause of an error can be checked with the link special relay (SB) and link special
register (SW) of the station No. for a station where the error has occurred.
No.
SB0065 Loopback status
When a cable is incorrectly connected to another station
Ex.
Control station
No.1
IN
OUT
Description
—
Normal station
No.2
IN
OUT
CHAPTER 8 PROGRAMMING
Page 526, Section 10.3)
No. Description
SW0065 Loopback information
SW0070 IN-side loopback station No.
SW0071 IN-side loopback factor
SW0072 OUT-side mis-cabling station No.
SW0080 OUT-side loopback station No.
SW0081 OUT-side loopback factor
SW0082 IN-side mis-cabling station No.
Normal station Normal station
No.3 No.4
IN
OUT
IN
OUT
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