Remote speed control on VFD

[Islander71]

After recommendations on here I bought one of the remarkably cheap AT1 VFDs off Aliexpress., and with help from a member have got it running my Wadkin wood lathe with remote switching and reversing sorted. The motor seems to be giving more torque than when using the original static inverter. When set for the frequency to be controlled by the unit's control knob it varies from the 20c/s to 65c/s which I've programmed in, but when set to be controlled remotely via a 10k potentiometer with wires to ground Vil and 5v, it will only vary between 20 and 42 c/s. Tried wire direct from Vil to ground, then to the 5v, and still only the 20 - 42 c/s. It has a 12v terminal so I moved the wire going to the 5v to that which has given me the 20 - 65 c/s. But now I'm worried that the higher voltage may damage the unit. Should I set it pack to the VFD's control or is it safe to leave it connected to the 12v, ViL ,and ground?

 

[mattg]

The AT1 pdf shows the supply to be '5v/10v'. I cant immediately see a parameter to adjust it - is there possibly a jumper or some other physical switch to change it?
Alternatively it looks like parameter p73 and p74 can be used to adjust the analogue input range.

 

[Islander71]

Thanks for replying Matt. There are 2 terminals, at 5v and 10v ( not 12v as I had said). It was connected to the 5v as shown in tutorials, but that didn't give the full range, so I've connected to the 10v one. Just not sure if that will cause damage.
I have no idea what P73 "Max Ext Analogue" variable between 0-65535 and factory set at 31440 actually means, so am reluctant to alter it.

 

[Islander71]

Quick update. With the lead to the 10v terminal, the frequency reaches the max set at 65c/s before reaching the limit of the potentiometer. If I go past that point the frequency suddenly becomes unpredictable before dropping to the minimum set of 20c/s and then will not respond to the control for some time. So I'm guessing its not doing the unit any good, so for now I've put it back to being controlled by the VFD's potentiometer.

 

[Seadog]

You do have one of the terminals connected to ground, I hope?

 

[Islander71]

You do have one of the terminals connected to ground, I hope?

Yes.

 

[RichardM]

Can you post some photos?
What is the actual vfd?
Is it this?https://www.manualslib.com/manual/2817548/Xsy-At-Series.html?page=12#manual

 

[Islander71]

Yes, it looks like the one you've linked to. But I can now answer my own question - will connecting the pot to the 10v instead of the 5v terminal damage it? Yes it does! On the remote frequency control, twiddling the pot has no effect now it stays at 20c/s regardless, though occasionally briefly increasing erratically before returning to the 20. Luckily setting it back to control from the unit does still work. I guess I haven't really lost anything as it was no use when set at the correct 5v terminal as that only allowed the frequency speed to a max of 42, so the motor running slower than it should.
Either there was a fault in the unit to stop the remote operating correctly, or there must have been an additional parameter that should have been altered, though I cannt see what.

 

[Islander71]

Reading the manual the unit linked to is slightly different. This is the one I bought - https://www.aliexpress.com/item/100...o.order_list.order_list_main.5.28f518020Yaxri It is an XYS AT1.

 

[RichardM]

Pot should be attached to Com, Vi1 and 5v with Vi1 being from the pot wiper.
Pogramme10 needs setting to 2.

Dirty setup works as it should.

 

[RichardM]

Reading the manual the unit linked to is slightly different. This is the one I bought - https://www.aliexpress.com/item/100...o.order_list.order_list_main.5.28f518020Yaxri It is an XYS AT1.

Xsy at1 is the one you have linked to. Do you have a link to the manual?
Did you alter the programming for external frequency control?
If you did check your potentiometer.
Have you altered any other programme values?

 

[Islander71]

I dont have a link to a manual for the XYS AT1 - it came with a single basic page of information. It was set to external frequency control. The potentiometer was supposed to be 10k but my cheap multimeter showed it about 6k. That should have still been in acceptable range I think. Programs were set for nominal motor speed (980rpm), min and max frequency - 20-65c/s. For external stop and start and reversing.

 

[RichardM]

the pot is only a voltage divider so should be ok at 6k. have you checked that the wiper is ok?

 

[tigdlo]

With the speed set to maximum, wired as the photo above, measure the voltage between,

5V - COM
5V - Vi1
COM - Vi1

What do you get?

The Allen Bradley inverters I use have a setting to adjust the low and high point to allow full adjustment when using an external speed adjuster, the pot I used wouldn't adjust all the way to zero until I set the low point, I can't find a similar setting for your vfd but the documentation isn't the best.

 

[Dr.Al]

That inverter looks very similar to the one I used on my lathe build:

That one was quite strange. The manual (which I've got a scan of somewhere and can share if it's helpful) showed lots of different voltages and made it very unclear what was actually going on in the unit I had. After quite a lot of digging I found that the output (if memory serves me correctly shown in the manual as being for the potentiometer) was 5 V but the potentiometer input expected 0-10 V. There was also a 12 V output for the digital stuff.

That left me with a few options:

1. Use the knob on the front.
2. Connect the potentiometer to 5 V and only have half the speed range available
3. Do the same as #1 but configure it to run to 100 Hz instead of 50 Hz (as a cheat so that 5 V, or 50%, resulted in full speed)
4. Run the potentiometer off 12 V and risk over-volting the unit if the knob went round too far.
5. Run the potentiometer off 12 V and add another resistor in series so that it wouldn't reach full voltage (if you add 2 kΩ between the 12 V supply and a 10 kΩ potentiometer, the output of the potentiometer will vary from 0 to 10 V).
6. Find a 10 V supply from somewhere else.

I went with #1 for a while and then #6: I designed a new control box that had a linear regulator to drop the 12 V output down to 10 V to supply the potentiometer high side (I'm an electronics engineer so this stuff comes quite easily to me!). Details at this link. However, the other options are probably also valid.

I hope some of that is useful/relevant to you. Feel free to shout if there's anything I can help with. It might be worth scanning / sharing the user manual that came with your inverter (if it's like mine, the manual was only two sides of A3 so easy to scan!)

 

[Islander71]

The easiest thing to check was as RichardM suggested checking the potentiometer and lo and behold it had stopped working! Brand new unit bought off Amazon has lasted just 1 day. I found an ancient "Radio Spares" " Volume Control" lurking in a forgotten corner and it tested OK at 8K, so have fitted that and all seems to be working. I've put a simple stop on it so it can only just be turned far enough to get the max 65c/s which is probably at about 80% of its range.
I did check the voltage of the 10 or 12v tapping and found it to be 12.8v. I think putting a stop on the control knob will limit the voltage so less likely to do any damage.
Because it is being used in a very dusty wood environment, I have completely boxed the VFD in against a fractionally opened hopper window with just the small control unit fed through to the outside of the box, so not so easy to get to now without taking apart the box, so I'll leave it as it is as it appears to be working fine.
Many thanks for all the replies which has helped greatly.

 

[carbon]

Alternatively it looks like parameter p73 and p74 can be used to adjust the analogue input range.

Thats what Im thinking as well change parameter P73 to the max 65535 and this should allow the motor to achieve the max frequency set, rather than the percentage of the max value that you have set

 

[Dr.Al]

I did check the voltage of the 10 or 12v tapping and found it to be 12.8v. I think putting a stop on the control knob will limit the voltage so less likely to do any damage.

A 2.7 kΩ resistor in series with the potentiometer would also limit it to 10 V (actually 10.08 V, depending on resistor tolerance) and would be a bit more robust than a stop on the knob.

 

[Islander71]

Thanks Dr Al, that sounds a good idea.

 

[Islander71]

Sorry next query - what wattage resistor would it need - they seem to have 1/4watt up to 5w?