Mitsubishi Electric NZ2FTGN User Manual page 530

■Once - backwards
This function performs counting between the "Load value" and "End value + 1". The counting stops when the value exceeds
End value + 1.
It is used to perform down counting only.
To use this function in combination with the preset function, set the preset value between Load value and End value + 1.
Ex.
When Once - backwards is set (when "Counter behaviour internal gate" is set to "Interrupt counting")
Set SW gate
(b2 in "Control word" of Process data output)
Reset SW gate
(b10 in "Control word" of Process data output)
SW gate active
(b2 in "Counter status" of Process data input)
Internal gate active
(b5 in "Counter status" of Process data input)
End value reached
(b10 in "Counter status" of Process data input)
(1) When the Set SW gate is turned on, the counting starts.
When the counting starts, SW gate active and Internal gate active turn on.
(2) If Counter value goes below End value + 1 during down counting, Load value is stored in Counter value.
At this time, the counting stops automatically, Internal gate active turns off, and End value reached turns on.
(3) When Reset SW gate is turned on, SW gate active turns off.
(4) When Set SW gate is turned on, the counting restarts.
After restarting the counting, SW gate active and Internal gate active turn on.
(5) When Reset SW gate is turned on, the counting stops.
When the counting stops, SW gate active and Internal gate active turn off.
19 HIGH-SPEED COUNTER MODULE
528
19.1 NZ2FTS-D62P2
Counter value
Upper limit value
(+2147483647)
(1)
Load Value
0
End Value + 1
Lower limit value
(-2147483648)
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
(2) (4)
(3)
(5)