Inverters are being used more and more widely now. So how do we control inverters with PLCs? Below, I will briefly write out the methods we commonly use for your reference.
1. In a simpler way, the output frequency of the frequency converter is adjusted using the polarized input/output signals of a PLC. This is the common method of using external circuitry to drive high, medium, and low speeds. This method is simple to wire and has strong anti-interference capabilities. The PLC's digital output terminals can control the forward and reverse rotation of the frequency converter, and the speed and acceleration/deceleration time can be adjusted polarized.
2. The commonly used method is to use the analog output module of the PLC, namely the DA module, to supply the inverter with a DC voltage of 0-10V or a DC current of 4-20mA. This method is simple to wire and flexible to control, and is generally used.
3. High-speed pulse output signal as frequency command signal. Some frequency converters have high-speed pulse input function, so this method can be used.
4. Serial communication provides a frequency setting signal, allowing the PLC and frequency converter to transmit a large amount of parameter setting and status information. If both the PLC and the frequency converter have serial ports and can use the same protocol, the frequency converter can be easily controlled without adding any additional hardware, but familiarity with the communication protocol and design of the communication program is required.
These are some of the methods we commonly use.
