Inovance H3U Series - Page 353

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5
5 High-speed Input5.2.4 SPD Pulse Density Detection
1
)
Note:
X00 to X07 ports used for the SPD instruction can be used for high-speed counters or interrupt inputs.
2
)
Example:
●
Notes to actions:
D0
D1
D2
Measured pulse value
within the set time
Instant count value in
the measured period
Remaining time of the
measurement period
1000ms
X
7
X
0
1000ms 1000ms
In the gure above, when X7 is set to ON, D1 counts the X0 action which is from OFF to ON state, and
stores the result to D0 after 1000 ms. Then D1 is reset and counts again the X0 action. D2 is used to
measure the remaining time.
Therefore, the pulse frequency can be calculated according to the D0 and [S2] setting value. If the pulse
signal is measured by rotary encoder, the speed can be calculated.