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MELSEC-Q
9 PROGRAMMING
(6) Program example
(a) Interlock program example for remote master station and
remote I/O station
Provide interlocks depending on the link status of the remote master station
(local station) and remote I/O station (other station).
The following example shows communication program interlocks using the
link status (SB47, SB49) of the remote master station and the link status
(SW70 bit 0, SW74 bit 0, SW78 bit 0) of the remote I/O station (station No.
1).
Program for automatic communication function: Refer to (b) in this section.
SB47: Baton pass status(host)
SB49: Host data link status
SW70: Baton pass status of each
station
SW74: Cyclic transmission status
of each station
SW78: Parameter communication
status of each station
SB20: Module status
Set the following value in the timer constant K
.
Baton pass status
(T0, T2)
(Sequence scan time
4) or more
Cyclic transmission status
Parameter communication status
(T1, T3, T4)
(Sequence scan time
3) or more
Reason: To prevent control from stopping even if the network detects an
instantaneous error due to a cable problem, noise or other condition.
Note that "
4" and " 3" represent standard values.
POINT
For details of the interlock program for the remote master station and remote I/O
station of MLESECNET/H, refer to the "Q Corresponding MELSECNET/H Network
System Reference Manual (Remote I/O Network)".
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