
B-63983EN/02 4.LADDER LANGUAGE
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(b) Specify up and down
The signal REV changes according to the then direction of
rotation. It becomes 0 for forward rotation and 1 for reverse
rotation. Thus, the counter is an up counter for forward
rotation and a down counter for reverse rotation.
(c) Reset
In this example, since W1 is not used, RST = 0, and contact
B of L1 is used.
(d) Count signal
The count signal POS turns on and off 12 times each time
the rotor rotates once.
(2) Counter number and W1
In this example, the second counter is used. The result of W1 is
not used, but its address must be determined.
(3) Operation
(a) Setting the preset value
Since the rotor to be controlled is 12-angle as shown in Fig.
4.4.1 (d), 12 must be preset in the counter. It is set from the
counter screen.
(b) Setting the current value
When the power is turned on, the position of the rotor must
be equated with the count on the counter. The count is set
via the counter screen. Once a current value is set, then
correct current positions will be loaded to the counter every
time.
(c) The POS signal turns on and off each time the rotor rotates.
The number of times of the POS signal turns on and off is
counted by the counter 2, as below.
1, 2, 3, . . . 11, 12, 1, 2, . . .
for forward rotation
1, 12, 11, . . . 3, 2, 1, 12 . . .
for reverse rotation