Mitsubishi MELSEC-A series Programming Manual

APP - 35
APPENDICES
Appendix 1.4 Special registers for Link
The link special register stores the result of any error, etc. which may occur during data
communication as a numeric value.
By monitoring the link special register, any station number with an error or fault diagnosis
can be read.
These special registers are applicable to all types of CPUs except the A3V.
For description of the special registers for link for the A3V, refer to the A3VTS Data Link
System User’s Manual.
(1) Link special registers only valid when the host station is the master station
Table 1.5 Link special Register
Number Name Description Details
D9200
LRDP processing
result
0: Normal
2: LRDP instruction
setting fault
3: Corresponding
station error
4: LRDP cannot be
executed in the
corresponding
station
Stores the execution result of the LRDP (word device read)
instruction.
• LRDP instruction setting fault:
• Corresponding station error:
• LRDP cannot be executed in the
corresponding station:
Faulty setting of the LRDP
instruction constant, source,
and/or destination
One of the stations is not
communicating.
The specified station is a
remote I/O station.
D9201
LWTP processing
result
0: Normal
2: LWTP instruction
setting fault
3: Corresponding
station error
4: LWTP cannot be
executed in the
corresponding
station
Stores the execution result of the LWTP (word device write)
instruction.
• LWTP instruction setting fault:
• Corresponding station error:
• LWTP cannot be executed in the
corresponding station:
Faulty setting of the LWTP
instruction constant, source,
and/or destination.
One of the stations is not
communicating.
The specified station is a
remote I/O station.
D9204 Link status
0: Data link in forward
loop
1: Data link in reverse
loop
2: Loopback in forward/
reverse direction
3: Loopback in forward
direction
4: Loopback in reverse
direction
5: Data link impossible
Stores the present path status of the data link.
• Data link in forward loop
• Data link in reverse loop
• Loopback in forward/reverse loops
Master
station
Station 1
Station 2
Station n
Forward loop Reverse loop
Master
station
Station 1 Station 2 Station n
Forward loop Reverse loop
Master
station
Station 1 Station 2 Station n
Forward loo
p
back Reverse loo
p
back
Station 3

Mitsubishi MELSEC-A series Specifications

General

Brand	Mitsubishi
Model	MELSEC-A series
Category	Controller
Language	English