PM DRO's

[phazertwo]

Anyone have some experience and opinions on the PM DROs? Specifically the scales themselves. For my use I don't need the actual read out, but it would be nice to have.

I would like to use them to map my ball screws, and possibly use them for feedback in the future. I've looked at Accurite but it's going to be over $1500 just for the scales, where as PM is $499 for the whole kit and caboodle. I would assume that PM uses a Chinese vendor that is probably not in the same league as Accurite, but if it works, it should be good enough...

One of the issues I think I might run into is I need to know the pin out of the DB9 connection, so if anyone knows if that is in the documentation, that would be great.

PZ

 

[kb58]

You'll probably have better luck asking on the CNC forums. I have a PM DRO, but since it was already installed, there's nothing to do other than use it. Even if I had installed it, the DB9s are already wired and just plug in. What you're asking for is much more hardware/electronics-centric.

 

[MSD0]

I just replaced one of the glass scales (Sino DRO) on my PM-1127VF-LB with a Easson GS31 from DRO pros. The pinout was the same for both scales.

 

[phazertwo]

At this point, I'm far more interested in your opinion of the DRO and scales themselves. Are they consistent and accurate? Do they sometimes miss count for no apparent reason? What is your general feeling on the quality of the scales and the setup as a whole? What, if any, other issues have you had with them?

This is actually a VERY long way away form being integrated into a CNC controller. For now it will just be a DRO that I can use to map the ball screws, and use as a sanity check on sensitive parts.

I just replaced one of the glass scales (Sino DRO) on my PM-1127VF-LB with a Easson GS31 from DRO pros. The pinout was the same for both scales.

Why did you replace the glass scale? Was there an issue with them, or was it an upgrade?

PZ

 

[kb58]

The problem with the question is that users (including myself) often have nothing to compare it to. Do I like it? Yes (having not used a DRO before). Is it accurate? I don't know and haven't checked. Has it skipped readings? I don't know.

 

[7milesup]

Phazertwo...

I just installed a set of glass scales on my PM833T mill. You will find that almost all of these products come from the same place out of China. My system is identical to PMs but at half the price. The supplier did mess up my order and sent a two axis head instead of a three axis head but he made it right, so I am very happy.

https://www.aliexpress.com/item/fre...216.html?spm=a2g0s.9042311.0.0.6db94c4dKev7LF

I have not had mine very long but so far it has been flawless. As you probably already know, the method of mounting has a lot to do with reliability. For example, does the read head have proper tolerances ie: is it binding at some point. Is the scale mounted in such a fashion that will allow swarf and cutting fluid to enter into the scale cavity (I mounted mine upside down).
The big difference between the one I bought and the one PM sells is service. Matt will take care of you. However, I was well taken care of from the seller on AliExpress too. Another interesting note is that the manual I received with mine is quite good. I was expecting a Chinglish monstrosity but very pleasantly surprised at how well it was documented.

Not sure if any of that helps but I will bet that the accuracy of the chinese scales is just as good as a more expensive brand. I think the area you would see the biggest difference is in the head. Display clarity, ease of use, etc are much better on the higher end models.

 

[MSD0]

At this point, I'm far more interested in your opinion of the DRO and scales themselves. Are they consistent and accurate? Do they sometimes miss count for no apparent reason? What is your general feeling on the quality of the scales and the setup as a whole? What, if any, other issues have you had with them?

This is actually a VERY long way away form being integrated into a CNC controller. For now it will just be a DRO that I can use to map the ball screws, and use as a sanity check on sensitive parts.



Why did you replace the glass scale? Was there an issue with them, or was it an upgrade?

The scale got contaminated with oil (chip stuck between read head and seal). I thought I saved it by cleaning in an ultrasonic cleaner, but it started missing steps and was inaccurate. The new scale was also an upgrade (1 micron vs 5 micron), so I now have .0001 resolution on the display.