Controlling a VFD with eth400

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Controlling a VFD with eth400

Postby Gadget » Wed Dec 27, 2017 8:01 pm

How does it work with vfd control in uccnc?
I have the eth400 and I understand how to control it with 0-10v but if I do not have the usb interface with feedback from the vfd, can I still input an "assumed" rpm at a specific voltage.
Let's say I measure a specific rpm at a known frequency/voltage output, can I then input that value in uccnc?
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Re: Controlling a VFD with eth400

Postby cncdrive » Wed Dec 27, 2017 8:46 pm

If you will use the UC400ETH only and want the UCCNC to show the Sact actual spindle speed then you have to get a frequency signal which represents the rotational speed of the spindle.
That signal you can connect to any input pins of the UC400ETH and the signal has to be a TTL 0/5volts digital signal and the frequency of the signal has to be proportional to the spindle speed.
You can then configure that input pin to the Spindle encoder Index signal and then the UCCNC will measure and show the speed based on the index prescaler setting and the input frequency.

Ofcourse you could "hack" the UCCNC to get in a signal in different routs, e.g. you could send in data via modbus via an external modbus device (e.g. an Arduino programmed as a modbus slave) and show the value in a DRO with reading the associated modbus registers using a macroloop or a plugin.
If you would have a UC300ETH then you could also connect in a 0-10V signal to an analog input pin and read it's value and put it in a DRO. However the UC400ETH does not have analog ports, so this is not possible with the UC400ETH.

And to have a closed loop spindle speed control for that you need an incremental encoder with at least A and B channels and configure that as the spindle encoder and then configure the PID controller for the spindle speed control.
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Re: Controlling a VFD with eth400

Postby Gadget » Wed Dec 27, 2017 9:07 pm

Thanks for the quick reply.
This is the vfd I will probably use
When I was looking into this briefly on google I got the impression that I needed the usb dongle with 2 ports for vfd feedback but you are telling me I can connect the feedback directly to the eth400?
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