siemens micromaster 430

I think this is nothing to do with VFD setting. Air compressor usually come with pressure switch to shut down the compressor once the max pressure reached.

If I guest you right, You have a screw compressor (maybe ATLAS COPCO...) with VFD siemens Micromaster 430.

You want to use this directly without the dedicated PLC controller supplied with the compressor ?

I can only give some hints on the way to control the Inverter with the PID but you need to do most of the parameters settings yourself. Always try the settings with the motor uncoupled from the compressor and do some simulation on the feedback to verify it is working the way you want:

- PID feedback input must be from a pressure transducer giving the required 0 to 10V signal to cover the range of pressure you want. Select the PID feedback location parameter P2264 to be 755.01 which means that you will use the Analog Input 2 for this feedback.

- PID Set point input should be also an analog signal entering Analog input1, and also varies from 0 to 10V.

This setpoint signal must be rigged so that you can set the pressure required by varying the signal value. (Potentiometer can be used...).

The PID will compare the 2 input signals and will increase/decrease the motor frequency to increase/decrease the rpm and attain the required pressure and maintain it.

the minimum and maximum rpm are set somwhere else.

All the PID controller parameters should be looked at and understood to set them properly for the operation to be correct. Do tests without driving the compressor element but only the motor. Rig the feedback to simulate pressure values and see if you have selected the parameters correctly.

I hope that you only needed the above info Otherwise i cannot pretend to configure it completely for you. This would require more checks and some experience in using the same installation whish I do not have now.

The OEM PLC does the PID Job externally and controls the frequency of the inverter directly.

Hi Lucke,

thank you so much for the help. this is my first time to configure the siemens vfd. furthermore, as i have read on the manual, on the application macro, MM430 is only applicable for pumps and fans, just want to be clarified if these MM430 is also applicable for air compressor?

once again, thank you so much

For Piston Compressors, you need to make sure that the VFD can be set to constant torque in the first place. Also, there will be a minimum rpm for this type of compressors not to go below otherwise you will compromise the efficiency and affect the smoothness of the running... But for the screw types and centrifugal compressors, it will be easier to work with. Atlas-copco uses the MM440 series.

thanks for the assistance. i can now have the option.

much appreciated