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8.3.7
Scan synchronous function
This function selects whether to synchronize or not the link scan with the sequence scan.
(1) Synchronous mode
Performs data linking using the scan that is synchronized with the program.
(The sequence scan and link scan start at the same time.)
In the synchronous mode, the link scan interval becomes longer when the sequence scan takes long because the
link scan is synchronized with the sequence scan.
● While in the synchronous mode, the sequence scan time must not exceed the time specified for the corresponding
transmission speed, as listed below.
If the scan time exceeds the specified time, a time out error occurs at each station.
Transmission speed
10Mbps
5Mbps
2.5Mbps
625kbps
156kbps
● The asynchronous mode is recommended for a mixed system of local stations A1SJ61BT11 and A1SJ61QBT11 when
the L series master/local module is used as the master station.
When using a system that uses the L series master/local module as the master station in the synchronous mode, make
sure to observe the restrictions in (a) and (b) below.
• When using a system consisting of both the A1SJ61BT11 and A1SJ61QBT11 as local stations, set the sequence
scan time of the local station CPU to be shorter than ST.
For more details on "ST", refer to
• When using a system consisting of the QJ61BT11N as the master station in the synchronous mode and both the
A(1S)J61BT11 and A(1S)J61QBT11 as local stations, use XnC as an interlock of the FROM/TO instructions on
the local station CPU side.
● When operating in the synchronous mode, the "L RUN" LED may be lit dimly.
(2) Asynchronous mode
Performs data linking without synchronizing with the program.
(3) Setting method
Set the scan synchronous function in "Scan Mode Setting" of the network parameter setting in GX Works2. (Refer
to
Page 77, Section 7.3.2 to Page 99, Section 7.4.2.)
182
Sequence scan time
50ms
50ms
100ms
400ms
800ms
Page 430, Appendix 4.1.
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Troubleshooting
