Mitsubishi Electric Melsec QJ71LP21 Reference Manual page 86

3 SPECIFICATIONS
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(4) SB/SW when a communication error station/communication stop
station occurs on the network
The status of whether there are any communication error/communication stop
stations on the network can be checked with the link special relay/link special
register (SB/SW).
Use them as interlocks for programs.
For interlock program examples, refer to Section 6.1.2.
Link special
relay/link
special
register
Shows the communication status between the
SB0020
network module and CPU module.
SB0047 Shows the baton pass execution status of the host.
SB0049 Shows the cyclic transmission status of the host.
Shows the baton pass execution status of all
stations (including the host). However, it only shows
SB0070
the status for the number of stations set with
parameters.
Shows the baton pass execution status of each
SW0070 to
station.
0073
Each bit corresponds to the status of each station.
Shows the cyclic transmission status of all stations
(including the host). However, it only shows the
SB0074
status for the number of stations set with
parameters.
SW0074 to Shows the cyclic transmission status of each station.
0077 Each bit corresponds to the status of each station.
Shows the low-speed cyclic transmission status.
SB007A,
The transmission completion is indicated by the
007B
on/off status of either bit SB007A or 007B.
Indicates the redundant system status (control
SW01FC to
system/standby system) of each station. Each bit
SW01FF
corresponds to the status of each station.
*1: Signals for the stations in other than a redundant system are off.
Link special relays and registers
Description
MELSEC-Q
Signal status
Off On
Normal Abnormal
The baton The baton
pass is being pass is
executed stopped
Normal Abnormal
Occurrence
The baton
of
pass is being
communicati-
executed on
on stop
all stations
station
The baton The baton
pass is being pass is
executed stopped
Occurrence
All stations
of abnormal
normal
station
Normal Abnormal
SB007A
SB007B
Low-speed cyclic interval
Control Standby
*1
system system
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