How can PLC communicate with frequency converter through analog quantity?

First, open the smart programming software, then configure the hard line, and select st3o.


Because our actual PLC is ST30, it is necessary to conform to the actual. Then select the extension module, and there is only one here, and we choose AM03.


After selection, the analog output of the module is set. This (2ai/1aq) is two analog input and two analog output. Today I only set analog output.


This place can be selected voltage or current, according to your actual situation. We are connected with voltage now. The voltage is selected in this place. The range is positive and negative 10V, and the positive and negative 10V contains 0-10V. Other ones will not be moved. Then click to confirm, and the hardware configuration will be assembled.


Next, start writing programs. Here is a very important thing. You must master the analog conversion library.


After you click open the analog library, select the bottom RTI, and write a direct call smo.o. here. What does this mean? Next, I will introduce you to each corner.
The first input is the input, that is, the frequency you want. For example, if you want 50 Hz, you can write 50 Hz. Then you say I want him to be between 0-25, and any number can change. Then you write a VD0 address and write a memory. Ish represents the maximum value of the frequency you want. Our maximum value is 50.0, that is, 50 Hz, ISL represents the minimum frequency you want, which is 0.0.
What do the following Osh and OSL mean? They represent the maximum and minimum values of our analog output.


I will write you 27648 directly now, that is, your 0-10V voltage signal, then the corresponding PLC is 0-27648, the minimum value is 0, the maximum limit is 27648, which just corresponds to our frequency of 0-50 Hz. So this is output is output, and the output is analog quantity. The value of analog quantity is between 0-27648. A change of value, where is it stored? Store in the place just as shown.


You can see that the channel address is aqw16, that is, you are going to fill in this address, and all the other ones are wrong. You must fill in this. Here you write an aqw16. You can see this value from here. The change range is between 0-27648 with the change of your frequency. We write the program and download it to the PLC.


matters needing attention:


one After downloading the program to PLC, do not click Run.


two Remember to set the parameters of the inverter.