PLC control program case, frequency converter running at multiple speeds

The frequency converter is controlled by multi-stage speed. When it senses proximity switch 1, it runs at low speed. During operation, it encounters proximity switch 2 and runs at high speed. There are two ways to write the program: the first is hardwired control. When the proximity switch senses it, the PLC immediately outputs the corresponding terminal to control the speed. The other is communication writing frequency. When proximity switch 1 is sensed, the preset low speed frequency is written. When proximity switch 2 is sensed, the preset high speed frequency is written.

Firstly, let's take a look at the multi-stage speed control of the frequency converter, as shown in the following figure:

Explanation of Huichuan MD200 frequency converter on multi-stage speed

The specific program of the multi-stage speed program is as follows:

If communication is used to write frequency, the program will add the following on top of:

By using communication methods, changing the frequency can be very convenient. Using multi segment speed and changing the frequency can be relatively cumbersome. If you don't remember to operate, you still need to look up the manual.

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