Sino KA800MC

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GuustFlater

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Hi, I have mounted scales on my 60 year old Maximat Standard. For the cross slide I used a Sino KA800MC magnetic read head, since i have limited space. Unfortunately I have strange issues when calibrating this specific axis. Everything works normal up to a certain moment where the reading keeps on increasing/decreasing while the slide is stationary. It can happen both when moving high speed and while accurate positioning. It does not happen all the time, but off course this results in an unusable DRO.
I have aligned the read head perfectly, using a feeler gauge to have a consistent distance and avoid skewed setup.
I really have no clue where to look. It happens even when no motors or any other electrical appliance in the neighborhood is running, so for me that rules out interference. All signal wires are guided through metal sleeves.
Anyone who can point me into a solution direction?

Merry Christmas to all of you!

Marko
 
Try swapping scales to the readout to determine if the problem is a scale or readout issue
 
GuustFlater said:
Hi, I have mounted scales on my 60 year old Maximat Standard. For the cross slide I used a Sino KA800MC magnetic read head, since i have limited space. Unfortunately I have strange issues when calibrating this specific axis. Everything works normal up to a certain moment where the reading keeps on increasing/decreasing while the slide is stationary. It can happen both when moving high speed and while accurate positioning. It does not happen all the time, but off course this results in an unusable DRO.
I have aligned the read head perfectly, using a feeler gauge to have a consistent distance and avoid skewed setup.
I really have no clue where to look. It happens even when no motors or any other electrical appliance in the neighborhood is running, so for me that rules out interference. All signal wires are guided through metal sleeves.
Anyone who can point me into a solution direction?

Merry Christmas to all of you!

Marko
Click to expand...
Marko,
So the first problem is that Sino doesn't exist anymore, and definitely doesn't make magnetic scales (Sino used to a trademark for a Chinese company that went out of business a couple of years ago). There are many-many sellers in China now that use that name. One of them is the former Sino distributor, who now sells Ditron scales rebranded as Sino. I found only two listings for KA800MC (one on eBay and another on AliExpress) from an unknown sellers: https://www.ebay.com/itm/403953278560 and https://www.aliexpress.us/item/3256802580450669.html. Those don't look like Ditron magnetic scales. The are closer to the scales to SIEG ships with their DROs, but appear to be chrome plated. There are some similarities in description (like "Ulnar band TR50 at 5 + 5mm intervals") so I'd wager to say that this is the same seller.

All this said, I've never seen a magnetic scale do what you describe. You didn't say what you are connecting this to (TouchDRO vs. something else). A quadrature counter would not "climb" when the signal is noisy, instead the reading would flicker. I've never heard of quadrature scales doing this, and I can't fathom the sort of noise that would cause 5V signal spikes. On top of that, they would need to be just the right sort of noise to trick a quadrature counter to think it's getting phase-offset quadrature signal.
For the position to climb while the scale is stationary, the interpolation circuit in the scale would have to output the counts.

Hope this helps
Yuriy
 
Hi, thank you for your extensive reply. To be honest this is a project started several years ago and has been post-poned due to several reasons. I have bought the "Sino" KA800MC read head with tape on Ebay about 3 years ago. No clue if it is a real Sino, but it looks a pretty decent product, well made and finished. Wiring and connector look pretty nice as well. But anyway it is a magnetic read head, with quadrature signal. In the same period I made a touchdro board (with custom PCB), based on a schematic that was on your yuriystoys website (I cannot find the schematic anymore), with an arduino and HC-05, so very vintage.... I used the exact schematic including the LS7366 quadrature decoding IC.
Good to hear the quadratic scales would not "climb" on noisy signal.

Could bad alignment of the read head (although I think it is pretty perfect aligned) be a reason for climbing values?

Otherwise I see two options: Or the read head is bad (a lemon), or the arduino board might be flaky, not capable of handling the signals. I might opt for the latest ESP32 based controller. The other two scales (bed and vertical milling head) are iGaging EZ-View Plus scales. These work ok. I have a third iGaging scale for the cross slide, but it almost impossible to install this one without blocking a lot of travel.

Which ESP32 TouchDRO version should I use for this combination?
 
Last edited:
GuustFlater said:
Hi, thank you for your extensive reply. To be honest this is a project started several years ago and has been post-poned due to several reasons. I have bought the "Sino" KA800MC read head with tape on Ebay about 3 years ago. No clue if it is a real Sino, but it looks a pretty decent product, well made and finished. Wiring and connector look pretty nice as well. But anyway it is a magnetic read head, with quadrature signal. In the same period I made a touchdro board (with custom PCB), based on a schematic that was on your yuriystoys website (I cannot find the schematic anymore), with an arduino and HC-05, so very vintage.... I used the exact schematic including the LS7366 quadrature decoding IC.
Good to hear the quadratic scales would not "climb" on noisy signal.

Could bad alignment of the read head (although I think it is pretty perfect aligned) be a reason for climbing values?

Otherwise I see two options: Or the read head is bad (a lemon), or the arduino board might be flaky, not capable of handling the signals. I might opt for the latest ESP32 based controller. The other two scales (bed and vertical milling head) are iGaging EZ-View Plus scales. There work ok. Which ESP32 version should I use for this combination?
Click to expand...
Hi Marko,
I never had an Arduino based quadrature adapter option, so you probably found it somewhere else. I'm not familiar with that design, but given that it uses a purpose-built quadrature decoder chip, it's unlikely that the chip is making up stuff. I'd say, go over the Arduino sketch and make sure that there is nothing silly going on there, and if it all looks OK, then there is a problem with the scale.

The ESP32-based DIY circuit can read iGaging scales and quadrature scales at the same time. There is nothing pre-made that can read both (without modifications). The iGaging board firmware can read quadrature scales, but the inputs are not 5V-tolerant, so they need a voltage divider or a buffer.

Regards
Yuriy
 
Hi Yuriy,
Ah, that's an interesting situation. Going through my development folder, I think I have the arduino software from Rysium. But still no clue where I got the electronic schematic from, if it is not from your site. Anyhow, this might be a source for the problems, since Rysium marks his firmware as Beta, and I haven't seen a final version. So a new interface board, based on the ESP32 with the latest (tested) software might be a step in the right direction.
I noticed your earlier posts that you won't sell the DIY kits anymore. So to have an interface that can handle combined capacitive and quarature based on a good design, I will develop my own PCB based on the schematic on your site. Is the 1.6 firmware compatible for me?
Again, thank you for your quick and informative replies!
Marko
 
Hi Yuriy, I build a new adapter board after above problems, based on your ESP32 schematic (since the 2 capacitive scales on my machine are not supported with your current adapters, which I can fully understand and accept). I flashed sw 1.6 and everything works really fine now. Thank you once again for your hard work. Since i did not buy an adapter board, but I'm happy with the product, I want to support you by making a donation. Do you have a PayPal account?
Marko
 
GuustFlater said:
Hi Yuriy, I build a new adapter board after above problems, based on your ESP32 schematic (since the 2 capacitive scales on my machine are not supported with your current adapters, which I can fully understand and accept). I flashed sw 1.6 and everything works really fine now. Thank you once again for your hard work. Since i did not buy an adapter board, but I'm happy with the product, I want to support you by making a donation. Do you have a PayPal account?
Marko
Click to expand...
Marko,
Glad you got it working, and thank you for the offer, but no need for a donation. I get a lot of help help and support from the community, so this is my donation back to the community. Plus, my hope is that if you are happy wit your TouchDRO unit, you might tell your friends, who will tell their friends, etc. ;)
Regards
Yuriy
 
ycroosh said:
Marko,
Glad you got it working, and thank you for the offer, but no need for a donation. I get a lot of help help and support from the community, so this is my donation back to the community. Plus, my hope is that if you are happy wit your TouchDRO unit, you might tell your friends, who will tell their friends, etc. ;)
Regards
Yuriy
Click to expand...
Take that, PS!
 
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