Which potentiometer to select speed for my VFD driven lathe spindle

[maxime.levesque]

I want to remotely control the spindle speed of my VFD driven lathe motor,
and I'd like to know if I'm understanding the info from manual (HUANYANG GT-Serie):

I have the choice between two analog input terminals, that have the following spec/descriptions:

AI1	Analog Input: -10V ~ 10v, input impedance: 20 kOhm
AI2	Analog Input: 0-10V / 0-20 mA, switched by J16, input impedance: 10 kOhm (voltage input) / 250 Ohm (current input)
J16	Switch between (0~10v) voltage input and (0~20mA) current input. V connect to GND means voltage input, I connect to GND means current input

I suppose that AI1 is meant for a potentiometer that also reverses voltage, since it goes from -10 to positive 10. I am assuming it is for cases where I want the ability to go in reverse by turning leftwards.

For a lathe this is NOT a good option IMO, and I would prefer to switch from forward to reverse by other means, and have a POT that only controls speed, from zero to max. So it seems that AI2 is the terminal I should use. but there are subtleties that are beyond my comprehension, so I'd like to get some advice on which POT I should get.

 

[woodchucker]

I have a Hyuang HY series and I use a 10k potentiometer . I guess they use different resistance for the GT.
I used buttons to reverse my mill the potentiometer does not reverse the motor.
I doubt yours reverses based on voltage, I just think it works with both + or negative voltage.

edit: this is what I bought for the 10k potentiometer

https://www.amazon.com/gp/product/B0B55XFWDC/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&th=1

 

[markba633csi]

I'm surprised the manual doesn't specify a pot value
Electronically speaking, the input impedance and the pot value would be two different things, but a value of 10K is low enough
that it could be the actual pot value- they don't clarify. Also they don't say how much current the +10v output can supply
Pretty sure you don't want to go larger than 10K to avoid picking up noise

 

[den-den]

You want a linear pot, either 0 - 5K or 0 - 10K should work. I prefer a single turn pot for speed control. There is no reason to spend much money on this item. Note that most pots do NOT come with a knob, check the shaft size and order a knob to put on it.

 

[woodchucker]

I'm surprised the manual doesn't specify a pot value
Electronically speaking, the input impedance and the pot value are two different things, but a value of 10K is low enough
that it could be the actual pot value
Pretty sure you don't want to go larger than 10K to avoid picking up noise

it does.. it specifies 10k pg 17 of the manual.. AI2

https://www.automationtechnologiesinc.com/wp-content/uploads/downloads/2018/08/GT-series-manual.pdf

 

[maxime.levesque]

@woodchucker that is the exact manual I have !

So I should use AI2 with a 10k Ohm resistor, and not AI1 with a 20kOhm resistor ?

Sorry, I'm an illiterate in electronics.

it does.. it specifies 10k pg 17 of the manual.. AI2

https://www.automationtechnologiesinc.com/wp-content/uploads/downloads/2018/08/GT-series-manual.pdf

 

[BrianVedack]

Did you ever get the potentiometer issue taken care of?

 

[maxime.levesque]

Did you ever get the potentiometer issue taken care of?

Yes, it's working !

 

[BrianVedack]

Awesome!