Scan Synchronous Function - Mitsubishi LJ61BT11 User Manual

8.3.7 Scan synchronous function

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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.
POINT
(1) 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
(2) 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.
(a) 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 Appendix 4.1.
(b) 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.
(3) 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 Section 7.2 to 7.5.)
10 Mbps
5 Mbps
2.5 Mbps
625 kbps
156 kbps
Sequence scan time
50 ms
50 ms
100 ms
400 ms
800 ms
8 FUNCTIONS
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