Mitsubishi Electric MELSEC Q Series Reference Manual page 31

(d) Detection of a faulty cable
A cable fault can be detected as a cause of a communication error. (
Control station
No.1
Normal station
No.4
(e) Detection of a cable insertion error
Incorrect cable connection between OUT and IN can be detected as a cause of loopback or disconnection from
the network. ( Page 128, Section 4.4.5)
Control station
No.1
IN OUT
OUT IN
Normal station
No.4
(f) Detection of a duplicated control station and duplicated station number
Duplication of the control station or station No. can be detected as a cause of loopback or disconnection from
the network. ( Page 129, Section 4.4.6)
When a station is added to a network (Station No. duplication)
Ex.
When a normal
station of a duplicated
No. is added
Normal station
No.4
Station No.
duplicated
Communication
error
Normal station
No.2
A cable fault is detected as the
cause of the communication error.
Normal station
No.3
Communication
error
Normal station
No.2
IN OUT
Incorrect cable connection between
OUT and IN is detected as the cause
of the loopback and disconnection.
Cable
IN OUT
insertion error
Normal station
No.3
Control station
No.1
Stations No.1 to No.4 continues
cyclic transmission.
Normal station
No.4
CHAPTER 1 OVERVIEW
Page 127, Section 4.4.4)
Normal station
No.2
Normal station
No.3
1
29