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8.1 Troubleshooting Flow
8.1.16 When "CAN'T SWITCH" Occurs to Control System CPU Module due to Communication Error when
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TROUBLESHOOTING
(2) How to cancel "CAN'T SWITCH"
Cancel "CAN'T SWITCH" detected by the control system CPU module after checking
that the standby system and the CC-Link IE Controller Network module or
MELSENET/H module operate normally by the special register.
A sample program to cancel an error by the error cancel command (M100) at the time
of "CAN'T SWITCH" occurrence is shown in Diagram 8.17.
In this sample program, when "CAN'T SWITCH" occurs to the control system CPU
module due to system switching request from the network module, an error "CAN'T
SWITCH" can be cancelled by turning ON the error cancel command (M100) after
checking that the standby system CPU module, CC-Link IE Controller Network
module, or MELSECNET/H module operate normally.
However, when systems cannot be switched by "other than system switching
request", "CAN'T SWITCH" cannot be cancelled in this sample program.
[Program example]
When executing the error cancel command automatically, change error cancel
command (M100) in Diagram 8.17 to be always ON (SM400).
(3) Programming of CC-Link IE Controller Network or MELSECNET/H
CC-Link IE Controller Network or MELSECNET/H network detects a temporary
communication error depending on conditions such as power supply ON/OFF or cable
and noise. Create the program using CC-Link IE Controller Network or MELSECNET/
H so that it will not stop control even when the temporary communication error is
detected.
For details, refer to the following manuals.
CC-Link IE Controller Network Reference Manual
Corresponding MELSECNET/H Network System Reference Manual
(PLC to PLC network)
Corresponding MELSECNET/H Network System Reference Manual
(Remote I/O network)
Diagram 8.17 Sample Program to Cancel an Error "CAN'T SWITCH"
An error "CAN'T SWITCH" (No.6220) is cancelled
when the system cannot be switched normally
(SD1589=0), system error information (SD1600),
and system switching request module No. from
the host system or other system network module
(SD1590 and SD1690) are all normal in the system
switching request by the network module (SD1588=3).
K0
M100
= K3 SD1588
0
= K0 SD1600
K0
SM50
<> K0 SD1589
= K0 SD1590
= K0 SD1690
MOVP K6220 SD50