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VFDs from Unitronics! One Solution for Control and Automation

Cara Bereck Levy


VFD, inverter, AC drive - engineers call these adjustable speed drives by different names, but all use them to control motor speed  and torque.

Now, you can obtain your VFDs from the same supplier as your PLC + HMI controllers. Unitronics VFDs can be used as a stand-alone product, or as part of a complete All-in-One package with our PLC+HMI controllers: UniStream®, Vision™ and Samba™.

This simplifies workflow by enabling you to:

  • Obtain your VFDs, PLC + HMI controllers and related components, as well as technical support, from a single supplier.
  • Operate your VFD directly from the controller’s HMI panel
  • Use the same programming software as the PLC control and HMI application, to:
    • Set-up and configure multiple VFDs in a snap
    • Monitor and debug your VFD 
    • Remotely Access your VFD

For more information, check out the VFD page in our website:



Recommended Comments

How many VFDs can I connect to one Unistream?

What if any are the limitations?

Can I read/control all of the I/O on each VFD? Even the analog inputs?

I'm looking to essentially use the VFD as a remote I/O unit since I only need a couple of I/Os and an analog input at each VFD. If I can control several VFDs from one Unistream and then use the Unistream as my gateway as well, all the better.



Mike Henry

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Hi Mike,
Since our VFDs are communicating using MODBUS RTU the limitation is 31 (If you need more then that you will have to add another modbus port and implement the communication manually) 

I\Os (digital and analog) can be red using communication so it seems that your paln should work.
Please note that since it uses a serial communication it is recommanded using the "read parameter" element instead of reading all values from every VFD and so improve the response time

  • Upvote 1
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Hi MIke,
After we double checked it seems you are right.

You need to connect a device on the Y1 or Relay output. Use Modbus 200BH, the corresponding signal can be output according to the setting value of Modbus. When it is set to 1, the output is ON, and when it is set to 0, the output is OFF. In this case, it's a way to send a virtual signal to Y1 or Relay output.

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