Appendix 2 Link Special Relay (Sb) List - Mitsubishi Electric QJ71LP21 Reference Manual

APPENDIX

Appendix 2 Link Special Relay (SB) List

No. Name
1 3
SB0000 Link startup (host)
(0)
1 3
SB0001
Link stop (host)
(1)
1 3
SB0002 System link startup
(2)
1 3
SB0003 System link stop
(3)
SB0005
Clear retry count
(5)
1
Clear communication
SB0006
error count
(6)
1: Used in the network tests of peripheral devices.
2: SB0000 to SB0003 become valid when only one point turns on.
SB0000
SB0001
3: Valid only when SB0047 is off. When it turns on (error), the last data are retained.
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The link special relay turns on/off by various factors that occur during data linking.
Thus, by monitoring or using it in the sequence program, the abnormal status of the
data link can be checked.
Moreover, the link special relay (SB) that stores the link status is used for the detailed
information of the network diagnostics of GX Developer. For a list of the device
numbers for each display item, see Section 8.1, "Network Diagnostics (Line Monitor)."
When multiple network modules are installed, the SB of each network module is
refreshed to the corresponding SB of the CPU module if each network module's refresh
parameters are not set. If the refresh parameters are set for at least one network
module, the refresh parameters of all the network modules should be reviewed.
Module installing position
Device number
In the link special relay, there are ranges the user can set on and off (SB0000 to
SB001F) and ranges the system can set on and off (SB0020 to SB01FF). (When the
unit mounting position is unit 1.)
Table 1 Special link relay (SB) list
Description
Restarts the host's cyclic transmission.
Off: Start not instructed
On: Start instructed (valid at rise)
Stops the host's cyclic transmission.
Off: Stop not instructed
On: Stop instructed (valid at rise)
Restarts the cyclic transmission according to the contents of
SW000 to SW004.
Off: Start not instructed
On: Start instructed (valid at rise)
Stops the cyclic transmission according to the contents of
SW000 to SW004.
Off: Stop not instructed
On: Stop instructed (valid at rise)
Clears the retry count (SW0C8 to SW0C9) to 0.
Off: Clear not instructed
On: Clear instructed (valid when on)
Clears the communication error (SW0B8 to SW0C7) to 0.
Off: Clear not instructed
On: Clear instructed (valid when on)
AB0001 is valid
SB0000 is valid
Module 1 Module 2
SB0000 to 01FF SB0200 to 03FF SB0400 to 05FF SB0600 to 07FF
2
2
2
2
2
2
[Availability column] Optical: optical loop, Coaxial: coaxial bus
MELSEC-Q
Module 3
Use permitted/prohibited
Remote
Control Normal
master
station station
station
Optical Coaxial Optical Coaxial Optical Coaxial Optical Coaxial
: Available, : Not available
Module 4
Remote I/O
station
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