Hi, I am using an EATON Variable Frequency Drive in a lab setting and was having trouble connecting it directly to my PC.

I am using this VFD: https://www.eaton.com/us/en-us/skuPage.MMX12AA7D0F0-0.html

My first attempt was to take an ethernet cord, cut off on end, and try to plug the data twisted pairs into the VFD. I was wondering if this effort could still be a solution (I am new to modbus and VFDs in general) and if I was plugging the wrong pairs into the terminals. I am using a Cat 6 Ethernet Cable.

After doing a bit more research I have found that there are usb to RS485 cables available. I was wondering if this would be a better solution, though I would like to avoid purchasing more material if possible. https://www.mouser.com/ProductDetail/FTDI/USB-RS485-WE-1800-BT?qs=sGAEpiMZZMsgSGrx0WqTbGAkhvJAByZv is the specific cable I was looking at.

Finally, the final option I am considering, though it is the least preferable, is to get the interface card that the VFD manufacturer lists in the data sheet.

 

Well, Ethernet is not going to work with the RS-485 inputs on your drive.

PCs do not normally support RS-485, you need an adapter; the FTDI device should work. Next you will need an application for your PC that has Modbus [master] capability.

 

What about Planet ICS 2105a ?
Or am I digging in the wrong direction?

 

You haven't said why this project needs Modbus communications. You might be better off with manual control - using a multi-turn potentiometer to control the VFD output.

If your approach is to "take an ethernet cord, cut off on end, and try to plug the data twisted pairs into the VFD" I think you're in over your head and you might consider seeking local help on this project. Connecting conductors with carrying unknown voltages to unknown connectors is a way to damage the electronics and blind efforts never work in industrial electronics.

Implementing Modbus is a project in and of itself. It is not plug-n-play. Understanding VFD's has its own learning curve.

System Integrators are the people who make their living connecting devices to each another to getting them to talk. A local electrical distributor who carries VFD's can probably provide the names of people who do this kind of thing.