Mitsubishi Electric MELSEC iQ-R Series Reference Manual page 23

■Pulse measurement mode (Synchronous pulse measurement function)
The pulse measurement value of the function input terminal's input pulse is retrieved at the inter-module synchronization cycle
start timing. The pulse measurement interval can be selected from four patterns: ON width, OFF width, rising edge to rising
edge, or falling edge to falling edge. (The synchronization latch pulse measurement value is updated only once during the
inter-module synchronization cycle.) By reading the synchronization latch pulse measurement value from the inter-module
synchronous interrupt program, the pulse measurement value of the input pulse just before the inter-module synchronization
cycle is started can be read out.
CPU module
High-speed counter module No.1 CH1
Measured pulse value
Synchronization latch measured pulse value
High-speed counter module No.2 CH1
Measured pulse value
Synchronization latch measured pulse value
Inter-module
synchronization cycle
Inter-module synchronous interrupt program
Normal program
Input Operation Output
refresh processing refresh
Read a synchronization measured pulse value.
Measured value 1
Measured value 1 Measured value 2
Measured value 1
sured value 1 Measured value 2 Measured value 3
Measured value 1
Inter-module
synchronization cycle
Inter-module synchronous interrupt program
Normal program
Input Operation Output
refresh processing refresh
Read a synchronization measured pulse value.
Measured value 3
Measured value 3 Measured value 4
Measured value 3
Measured value 4 Measured value 5
Measured value 3
5.1 Fixed Cycle Synchronization Function
Measured value 5
5 FUNCTION
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