36 COUNTER/TIMER FUNCTION BLOCKS
36.3 Up/Down Counter
1985
36
■Operation processing
In (n), set the maximum count value for up count and the start count value for down count. The valid range of (n) is 0 to 32767.
1. Counting up
• When (s1) changes from off to on, the value in (d3) is counted up by one.
• When (d3) reaches the (n) value, (d1) turns on and the counting stops.
• When (s3) turns on, (d1) turns off and (d3) is set to 0.
2. Counting down
• When (s2) changes from off to on, the value in (d3) is counted down by one.
• When (d3) is 0, (d2) turns on and the counting stops.
• When (s4) turns on, (d2) turns off and (n) is set to (d3).
3. Others
• When (s1) and (s2) change from off to on simultaneously, the value in (d3) is counted up by one with priority given to (s1).
• When (s3) and (s4) turn on simultaneously, (d3) is set to 0 with priority given to (s3).
■Operation result
1. Function block without EN/ENO
The operation processing is performed. The operation result is output from (d1), (d2), and (d3).
• Timing chart
When (n)=3
(1) When (s1) turns on, the value in (d3) is counted up.
(2) When (s3) turns on, the value in (d3) is initialized.
(3) When (s2) turns on, the value in (d3) is counted down.
(4) When (s4) turns on, the value in (d3) is initialized.
OFF OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON ON
(s1)
OFF
(s2)
OFF OFF
ON
ON ON
(s3)
OFF OFF
ON
(s4)
OFF
OFF
(d1)
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON ON
ON ON ON
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(d2)
(d3)
(1) (2)
(3) (4)