Several ways to write one-button start and stop of Siemens SMART200PLC

In production, due to factors such as installation environment, cost control, and ease of operation, one-button start and stop control will be used, such as motor control, valve control, etc. Today I will talk to you about several common writing methods. For the sake of intuitiveness and popularity, we use LAD (ladder diagram) to write it.

1.) One-button start and stop by bit command:

(One-button start and stop by bit command)

Program Description:

When the M10.0 button is pressed, M10.0 connects a scan cycle. In the first scan cycle, the normally open Q0.0

The contact is disconnected, the M10.1 coil loses power, the rising edge of M10.0 connects Q0.0 to energize, and the motor starts;

In the second scanning cycle, the normally open point of Q0.0 is closed, but the rising edge of M10.0 is disconnected, the M10.1 coil loses power, the Q0.0 coil loses power, and the motor stops.

2.) Bit Instructions

(One-button start and stop by bit command)

Program Description:

When M10.2 is pressed for the first time, the rising edge of the M10.3 coil is turned on and it is energized; within the same scan cycle, M10.3 is turned on and the Q0.1 coil is energized. It is turned on once within a scan cycle and is self-locking, realizing single-button start. In network 3, M10.2 is pressed again, the M10.3 coil is energized, the M10.3 normally closed point is disconnected, and the Q0.1 coil loses power, realizing single-button stop.

3.) One-button start and stop (set/reset)

(Reset/set one-button start and stop)

Program Description:

Press button M10.4, it connects the first scanning cycle, Q0.2 coil is energized and set to 1; press M10.4 again, Q0.2 coil is reset to 0; .5 is used as the auxiliary point of one-button start and stop, and the state of Q0.2 coil is consistent, and M10.5 is used as the normally closed point in the start network 1, and the normally open point of M10.5 is used in the stop network 2.

4.) One-button start and stop (position priority)

(One-button start and stop setting priority)

Program Description:.

Press M10.6, the rising edge of M10.6 generates a scan cycle, the normally closed point of Q0.3 is connected, the SR triggers S1 and R are turned on, the S1 terminal is set first, Q0.3 is set, Q0.3 normally open is closed, the motor starts, and the normally closed point of Q0.3 is disconnected.

5.) One-button start and stop (reset priority)

(One-button start/stop reset priority)

Program Description:

Press M10.7, and in the first scanning cycle, Q0.4 is turned on, and the normally open and normally closed terminals of Q0.4 are connected in series to the S and R1 ports respectively, forming an interlock, that is, only one port is turned on in one scanning cycle.

6.) One-button start and stop (counter)

(One-button start and stop counter)

Program Description:

Press M11.1, counter C0 counts to 1, and the current value of the counter in network 2 is compared with the number 1, which is exactly equal to 1, the Q0.5 coil is energized, and the motor starts; press M11.1 again, counter C0 counts to 2, and since the counter PV value is 2, the counter CO is reset, and the value of C0 is not equal to the current value 1, the Q0.5 coil loses power, and the motor stops.

When the current value of the counter is equal to 1, Q0.5 is turned on.

7.) One-button start and stop (addition)

(One-button start and stop addition)

Program Description:

Press the M11.2 button, VW4 is added to 1, and the result is stored in VW4; the value of VW4 is compared with the number 1, and they are exactly equal, so the Q0.6 coil is energized and the motor is powered on and started; when M11.2 is pressed again, the value of VW4 is compared with the number 2, and they are exactly equal, so the VW4 data is cleared and the motor stops.

8.) One-button start and stop (logic inversion)

(One-button start and stop logic is reversed)

Program Description:

The initial value of VB2 is 2#00000000. After pressing button M11.5, VB2 is inverted and the VB2 value is 2#11111111. At this time, VB2 low bit V2.0 is connected. Press M11.5 again, VB2 is inverted and the VB2 result is 2#00000000. At this time, VB2 low bit V2.0 loses power, and the cycle continues. V2.0 controls Q2.0. When it is energized, Q2.0 is connected, otherwise, Q2.0 is disconnected.

The above are the common one-button start and stop writing methods, of course there are more than these.