Hi all 🙂

I’m just setting up a DRO on my X1 milling machine and have finally got the second scale mounted … and whilst the DRO readout worked perfectly with the first scale, as soon as I added the second scale the readouts of both axes freeze / jitters by +/- 5um when the axes are moved.

If I unplug either of the linear scales the other one works just fine, which rules out an issue with either scale.

The DRO is by Vevor:

**LINK**

and the scales are by Warco:

**LINK**

Can anyone offer a suggestion as to what might be going wrong?

I’ve tried adding a ground wire from the DRO to the machine but it made no difference …

Many thanks for your help 🙂

David

Edited By David Hogg on 10/04/2022 13:12:27

Thanks for the quick replies!

Sorry, here’s the correct link for the DRO scales:

**LINK**

I will check when I’m back home but I did look at the specs for the DRO and the scales before I connected them together, and the pin-outs and voltages all looked the same.

Thanks again and will report back 🙂

David

Howard – they’re both identical scales. The third one I’ll be fitting on the Z axis is the same brand but longer.

Thanks 🙂

David

David – yes I’ve now tried all 3 scales on all 3 inputs, and on their own they all work fine.

I’ve done some more experimenting, and strangely, the 250mm scale that’s destined for the Z-axis works perfectly no matter what — whether it’s plugged in on its own, or whether one or more other scales are also plugged in, it always works. It was bought from the same page on the Warco website as the two 200mm scales, so the only difference should be the length … but something is obviously different otherwise it would also suffer the same freezing / jittery readout issue.

I’ve tried a few things including:

• Removing all the scales from the machine and laying them on wooden blocks — no difference.
• Checking the resolution setting of the DRO — 5um for each axis, the same as the linear scales
• Checking the pin outs for the DRO and scales — all match, with the same voltages
• Plugging each of the scales in on their own, in different sockets, and they always work flawlessly when they’re the only scale connected. As soon as a second or third scale is connected, neither of them work — unless one of them is the 250mm scale, which always works.
• Connecting a ground lead from the 4mm ground socket on the back of the DRO (marked PE?), and touching this to the suspect scale which is having reading issues … no difference.
• I’ve looked through the manuals of both the DRO and scales, and there aren’t any significant user-changeable options on the DRO such as changing the output voltage on the 9-pin connector, or changing the reading frequency, etc.

Also, on one of the reviews for the DRO someone said they got their scales from Warco and it worked fine, which is why I bought my scales there too…

One thing I did notice that may or may not be relevant, is that sometimes (not always), when you move one of the scales, the readout for one of the other connected scales (not the 250mm one though), jitters slightly as well. It’s as if there’s some cross-coupling interference between the two, which I imagine there shouldn’t be …

I’m at a bit of a loss what to try next, although I will be emailing the manufacturers of the DRO and scale tomorrow to see what they say.

Thanks for for your help!

David 🙂

Edited By David Hogg on 10/04/2022 20:08:10

The scales were from Warco but the screen was direct from Vevor … and although I’m not quite sure which is at fault, my money is on the DRO given that all the scales work fine on their own.

Have asked Vevor if I can send it back for a refund …

Cheers!

David

Hi everyone,

So Vevor have refunded me £30 of the £51 total cost as I guess it was too long since I bought it … anyone want a slightly suspect cheap DRO for parts? 😆

Cheers!

David