Variable Frequency Drivers (usually known as VFD´s), are very popular in industry because they can adjust torque and speed of AC motors by varying motor input frequency and voltage. The setpoint can be sent from a PLC and, therefore, from a computer, so this is what we are going to show you in this newsletter: how to send a setpoint to a VFD using a computer connected to an Ardbox PLC from Industrialshields. Hardware and considerations
Before starting the job, we will consider these points:
- The VFD has an analog input where we can send the setpoint. Therefore, the communication between the VFD and the PLC will be 4-20 mA.
- The Arduino programming environment has a built in serial reader and writer that makes it easier to debug and develop your Arduino code. This point is important taking into account that we will use the
Software and code
To communicate our Ardbox PLC with our computer we will use Serial communication. Serial communication just means that only one bit of information is sent a time. Most computers don’t have serial ports, but use a USB-to-serial driver to send and receive serial communication over USB So basically, inside loop(), we will check if any serial data has arrived with Serial.available(). If data has arrived and is available, store that data in a variable called setpoint, which we will use to send it to the VFD as an analog output. You can download the code here: Key Benefits
The main benefits of the Opiron purposed solution are:
- Easy: Easy is the first word that comes to our mind when we think in this application. Easy to install, easy to program, easy to send commands to the VFD!
- Open Source: Because open source means flexibility in terms of freedom to modify and integrate your system into more complex systems, and reliability.
- Useful: This project is useful because VFD´s are everywhere. See an example of VFD´s application in our blog.
Do you have a process to be automated? Contact Industrialshields to buy the proper hardware and to implement the entire solution.