Effects Of The Double Check System - Mitsubishi Electric MELSEC-Q Series User Manual

8.1.2

Effects of the double check system

(1) Input
Unless the master module receives the same data twice successively, data in the input area is not updated.
A minimum of one-transmission cycle time and a maximum of two-transmission cycle time are required as data
response time.
Therefore, when input data is shorter than two-transmission cycle time, the input data may not be captured
depending on the timing.
To ensure the response, provide an input signal that is longer than two-transmission cycle time.
Minimum data
response time
Maximum data
response time
(2) Output
As the double check is performed on the slave module side, the time required is the same as that for input,
namely a minimum of one-transmission cycle time and a maximum of two-transmission cycle time.
Sampling timing
Minimum of one transmission cycle time
Input data change
Sampling timing
Maximum of two transmission cycle times
Input data change
CHAPTER 8 TRANSMISSION TIME
Sampling timing
Input data update
Sampling timing Sampling timing
Input data update
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