Modern DROs and their scale interfaces

A while ago I bought a new to me lathe which was/is fitted with a (CHFOIC badged) DRO. My other machines have Anilam or Heidenhain DROs which have far fewer bells and whistles but have (touch wood) always been reliable.

My issue with the new DRO is that it is failing its Power On Self Test. It does the exact same thing when the scales are disconnected which leads me to believe that the head unit is faulty.

Information on the 'net seems to be really thin on this subject, but it seems that the interface to the X and Z scales is something called JCXE it uses a 9 pin connector.

I can't seem to find any sellers who will sell me a CHFOIC head unit on it's (i.e. not part of a kit with scales) so, what I really need is a head unit which is compatible with the scales I already have. Any suggestions or guidance would be most welcome -thanks for reading this.

I am not familiar with them but a quick Google search came up with a few hits and sellers on ebay

GUIYANG XINTIAN OETECH CO.,LTD, www.chfoic.com

Operation manual **LINK**

That looks remarkably similar to the Warco unit I bought & fitted a couple of years back, Might be worth checking out

Regards Mike.

Stueee

I have Chinese glass scales and found there are ar least two different wiring patterns for DB9 connectors linking the scale to the display.

I would recommend speaking to Machine DRO. They sell a number of adapters to connect different systems and have a lot of experience in this area.

Yes, trawling through eBay revealed that some of the Chinese suppliers used the same 9 pin physical interface on their scales, but with only 5 of the pins used.

I don't think the internal error code on the display unit can be caused by the scales being faulty or not connected. From your connector pinout it looks like the sales are pretty standard quadrature scales with the "R" signal being for a pulse which is generated as a reference point near one end of the scale travel. The "A" and "B" signals will be the quadrature outputs. As these signals are not at any fixed value the display unit has now way to know if the scales are faulty. Your scales are single ended output. If they were differential output they would have A+ and A-, B+ and B- and R+ and R-. As the scales are supplied with 5 volts the logic levels will be 0 and 5 volts. (These signal levels are often called TTL levels.) With power to the scales if you look at the "A" or the "B" signals with an oscilloscope you should see them changing state as the scales are moved. You will also need to know how many pulses per mm of movement that your scales provide. This can noemally be set with a setup function on the display unit. If you try to get into the setup function of your display then you may be able to see what the pulses per mm setting has been set to.I agree that Machine DRO will be able to tell you if their display units are compatible with your scales

Les.

Hi Stueeee

Check your inbox as I might be able to help

CS

Les,

The fault is a failed display startup self test both with and without the scales being fitted.

He's trying to match a new display to his existing scales

Try contacting machine dro. This one on their website might be suitable:

**LINK**

Stuart

Wrong button

Edited By duncan webster on 16/02/2023 19:55:18

I have recently fitted a DRO to my Boxford lathe, I ordered all the bit the same make but for some reason the display couldn't be shipped here (UK) and only one of the scales arrived but the other was unavailable so I ended up with 2 different brand of scales and a different make of display.

When I came to fit it, one of the scales worked but the other didn't luckily the one that didn't came with a 9 pin adaptor that did work with fitted I found this site explaining the different wiring very good.

https://www.touchdro.com/resources/scales/glass/glass-scale-pinout.html for getting the wiring right

But yours looks like a display problem.