Mitsubishi Electric MELSEC iQ-R-R6SFM - Page 394

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23 LATCH FUNCTION
23.1 Latch with Battery
■Timing of the latch processing
The timing of the latch processing is determined based on the effective range of the latch interval setting and the operation
setting for the specified latch interval ( Page 390 Setting the latch interval)
• When set to "Time Setting"
Latch processing is started in the END processing executed after the set time.
• The more the latch points, the more it takes to complete the latch processing. If the set time elapses while
latch processing is still executing, the next one is executed in the END processing that follows the
completion of the previous latch processing. Set a latch interval longer than the latch processing time so
that the specified time does not elapse during latch processing.
• If the latch interval is shorter than the scan time, latch timing occurs more than once within one scan.
However, latch processing is executed once during the END processing.
• When set to "Per Scan"
Latch processing is executed in the END processing of every scan. This setting allows to always retain the device of the
previous scan because the devices are latched at every scan. However, it may increase the scan time.
0
0
100 300200
200
400
300
10ms10ms
Time setting
(For 10ms)
Device memory
(Values from D0 to D99)
Backup power area
(Values from D0 to D99)
Program
1 scan
Time elapsed
Time elapsed
Write 400 to
D0 to D99.
Write 300 to
D0 to D99.
Write 200 to
D0 to D99.
Write 100 to
D0 to D99.
Data at this
time is latched.
Data at this
time is latched.
Latch processing
Powering off (resetting) the module at this time holds
D0 to D99 = 200.
Latch processing
100
1000
200
200
300
300
Device memory
(Values from D0 to D99)
Backup power area
(Values from D0 to D99)
Write 100 to
D0 to D99.
Write 200 to
D0 to D99.
Write 300 to
D0 to D99.
Program
Each scan
1 scan
Latch
processing
Latch
processing
Latch
processing
Latch
processing
Latch
processing
Latch
processing
Data at this
time is latched.
Data at this
time is latched.
Data at this
time is latched.
Powering off (resetting) the module at this time holds
D0 to D99 = 200.
1 scan 1 scan