1. Single button control motor start and stop.

① The counter is used to control the start and stop of the motor, and the control circuit only needs one button (x0). When the button x0 is pressed, the coil of the counter CO is powered on and counted through the M0 normally closed contact. The count value is 1 and equal to the set value 1. The contact of CO acts, the Y0 coil is powered on and controls the motor to start. In the first scanning cycle, although the Y0 contact is closed, the M0 normally closed contact is disconnected and C0 will not reset. When the button x0 is released, Y0 continues to be powered on.

② When the button x0 is pressed for the first time, the co coil is powered on, but it has reached the set value, so it will not be counted, and the count value is still 1. Because Y0 contact is closed, CO is reset, CO contact is disconnected, yo coil is powered off, and the motor stops. In the second scanning cycle, the normally closed contact of M0 is disconnected, and the co coil will not be powered on. When the button x0 is released, Y0 will still not be powered on. As shown below:

Start and stop the motor with PLC and counter

2. Control a disc with pluc

① The rotation of the disc is controlled by the motor. It is required to stop for 3S after each revolution and 5 revolutions after pressing the start button.

② A limit switch is used to detect the number of revolutions of the disc, and the control ladder diagram is shown in the figure below. The control principle is as follows: when the disc is in the initial state, if the start button x0 is pressed when the limit switch X1 is pressed, the Yo coil is powered on and self-locking, the disc rotates, and the limit switch X1 is reset. The counter CO is reset to 0, M1 is powered on and self-locking, and the timer T0 is connected to the circuit.

③ The disc rotates. When the bump touches and presses the lower limit switch x1, the normally closed contact of X1 is disconnected, the self-locking of Yo coil is released, the disc stops rotating, the normally open contact of X1 is closed, and M0 coil is powered on. Its function is to close the normally open contact of Mo in the second scanning cycle to prepare for the next rotation. The counter co counts once. The timer to is powered on and sends out a pulse with a delay of 3S, so that Y0 coil is powered on again and self-locking, and the disc rotates. The disc is counted once every revolution. When the count value is 5, the normally closed contact of counter C0 disconnects Y0 coil, and the whole process ends.

④ M1 in the figure is used to connect the timer T0 after starting to prevent automatic delayed starting when the original X1 contact is closed.

3. The following describes the use of high-speed counter.

(1) One phase one count input high speed counter.

① The number of one phase one counting input high-speed counter is c235 ~ c245, with a total of 11 points. Their counting mode and contact action are the same as those of ordinary 32-bit counter. When counting, when the count value reaches the set value, the contact acts and remains; When the count is reduced, it will be reset if it is less than the set value. The counting mode depends on the corresponding special auxiliary relays m8235 ~ m8245.

② The figure below shows one phase one count input high-speed counter. C235 in figure (a) has only one count input x0. When X12 is closed, m8235 is powered on, c235 is the minus count mode, and vice versa. When X12 is closed, c235 counts the pulse of count input x0. Like the 32-bit internal counter, in the counting mode, when the count value is greater than or equal to the set value, c235 contact acts. C235 resets when X11 is closed.

Start and stop the motor with PLC and counter

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