# Problem with defective board



## kevinismo (May 8, 2021)

Morning,
Hope somebody can help me with a problem. One of my scales is jumping all over the place. Not just a few thou, but over an inch.
I tried emailing Yuriy but he can't or doesn't wan to resolve this. 
I tried a different tablet, wrapped the cable with aluminum foil, mounted the scale on 3D printed standoffs but it still jumps. I'm at the end of my rope and if nobody can help me I will just thrash the DRO and get something from eBay. Doubt that the service will be any worse.
Kev.


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## JimDawson (May 8, 2021)

Glass scales?  Is it clean?  Is the error always in the same place?  Maybe time to connect an O-scope to look at the scale output.


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## markba633csi (May 8, 2021)

I doubt it's something you can fix externally, sounds like a chip failure in the read head.  Can you buy a replacement scale?
-M


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## kevinismo (May 8, 2021)

The scale is iGaging EZ-View DRO. I can get a new scale but there is nothing wrong with the scale. When I plug it into the iGaging display the position is solid. It only happens with Yuri's board.


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## ycroosh (May 8, 2021)

Kevin,
The board is not defective. There is something wrong [or at least different] with that scale. I can't help you more without either you capturing the outputs of the scale via an oscilloscope while it's jumping or sending the scale to me so I can do it.
Also, just to set the record straight, I've been trying to help you since October. Here is a quick recap:
You bought the adapter in July of 2018
In October of 2020, you sent it to me to look at, and even though I wasn't able to reproduce the issue, I replaced the board with the new revision.
In February of this year, you complained that the problem has gotten worse and sent the new board back. I reprogrammed it with the new firmware version and tested the crap out of it with the scales I have. I even sent you 3D-printed standoffs to isolated the scale from the machine's body. The problem didn't go away on your end.
I offered to test the scale and tell you exactly what's wrong with it if you send it to me. If there is something wrong on my end, I will cover the shipping. That said, I sell hundreds of these boards per year and on a bad year, I get no more than ten-ish boards with ANY issues (defects and customer damage). It's extremely unlikely that there is a bug in the firmware that is causing this problem, especially since yours is the only case with these symptoms.
In the few cases, I've seen before. the scale was bad, but those scales didn't work with the original display either. I don't have access to the iGaging code, so I don't know what magic they are doing to make that scale not jump. It's possible that there is something different with the signal timing. iGaging scales flip the data bit on the rising edge and need to be read on the falling edge of the clock signal. TouchDRO uses interrupts, so it reads the bit within a few nanoseconds of the falling edge. it could be that the data line is either not changing fast enough, or there is some jitter that is triggering the interrupt at the wrong time. 

It's plausible that the signal either doesn't fall fast enough (and the display somehow can compensate for it) or more likely, there is some sort of jitter that the display doesn't catch and TouchDRO does. I can probably see that pretty easily on the scope, but I can't afford to be sending you new boards in hopes that one of them will miraculously work. 
Regards
Yuriy


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## kevinismo (May 8, 2021)

I don't buy that I'm the only one with this problem. I saw hundreds of threads even on your forum with the same problem.


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## kevinismo (May 8, 2021)

Here are just a few links:
https://forum.yuriystoys.com/showthread.php?tid=118


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## ycroosh (May 8, 2021)

This is a different issue. Jumping of the last digit is inherent to how these scales work. All EZ-View and DigiMag scales do it. It happens when the scale is stopped between two discrete values and tiny fluctuations in capacitance nudge the reading up and down by one bit. Your scale is jumping by as much as an inch if I recall correctly.
Regards
Yuriy


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## RJSakowski (May 8, 2021)

I would suggest interchanging two scales.  If the problem goes with the scale, the problem is the scale.  If it stays with the same display position, the problem is with the display electronics.


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## kevinismo (May 8, 2021)

No. This is exactly what my scale is doing most of the time. It's not only the last digit. When I'm at 0.500" the display jumps to 0.499 and 
when I'm at 1.000" it jumps to 0.999" so it's all four digits jump up and down. This never happened with the igaging display.
Kev.


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## BladesIIB (May 8, 2021)

kevinismo said:


> Morning,
> Hope somebody can help me with a problem. One of my scales is jumping all over the place. Not just a few thou, but over an inch.
> I tried emailing Yuriy but he can't or doesn't wan to resolve this.
> I tried a different tablet, wrapped the cable with aluminum foil, mounted the scale on 3D printed standoffs but it still jumps. I'm at the end of my rope and if nobody can help me I will just thrash the DRO and get something from eBay. Doubt that the service will be any worse.
> Kev.


Your original post says it jumps over an inch. Your last post says .001” which is it?  Those seem pretty different?  Trouble shooting is about clearly defining the problem and narrowing it down to a repeatable problem so you can ultimately resolve the problem.


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## kevinismo (May 8, 2021)

yes, it's not jut the thousandths that are jumping. When I stop at 2.000", the inches digit is jumping too.


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## ycroosh (May 8, 2021)

OK, this makes a lot more sense. So the position is not "jumping by an inch". What you really meant was "the display is jumping, and when the scale stops at an inch boundary all digits are jumping/flickering".  I suspect that you are not seeing this with the other scales because they jump less frequently. I have one scale in my "library" that jumps up and down by 7 ticks at one spot. I wonder if yours is doing something silimar.
If you don't mind, do the following:
Set CPI for that axis to 1000. Then move the axis to a spot where the jumping is really bad and tell me what the min and max values are.

Regards
Yuriy


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## JimDawson (May 8, 2021)

kevinismo said:


> No. This is exactly what my scale is doing most of the time. It's not only the last digit. When I'm at 0.500" the display jumps to 0.499 and
> when I'm at 1.000" it jumps to 0.999" so it's all four digits jump up and down. This never happened with the igaging display.
> Kev.



Depending on the resolution of the system, that is only 1 encoder count.  That seems pretty normal.


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## BladesIIB (May 8, 2021)

kevinismo said:


> yes, it's not jut the thousandths that are jumping. When I stop at 2.000", the inches digit is jumping too.


Ok, but jumping from 1.999” to 2.000” is still just 0.001” or 1 thou and not inches. That sounds like what the seller is trying to explain above?  Just an outside observer here trying to help interpret. But that is what I am reading.


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## kevinismo (May 8, 2021)

ycroosh said:


> OK, this makes a lot more sense. So the position is not "jumping by an inch". What you really meant was "the display is jumping, and when the scale stops at an inch boundary all digits are jumping/flickering".  I suspect that you are not seeing this with the other scales because they jump less frequently. I have one scale in my "library" that jumps up and down by 7 ticks at one spot. I wonder if yours is doing something silimar.
> If you don't mind, do the following:
> Set CPI for that axis to 1000. Then move the axis to a spot where the jumping is really bad and tell me what the min and max values are.
> 
> ...


There is no one spot where the reading jumps. I moved all the way from left to the right and there are many spots. I don't want to list all of them but they are all the same. For example in one spot the scale flips between 1.436" and 1.439". Another spot is 2.757" and 2.760". Does this help?
What does 1000 CPI do? I had 2562 before. Should I change back?
Kev.


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## ycroosh (May 8, 2021)

Hmm, this is more than one bit. 
Changing the CPI to 1000 makes it so you can see the raw scale readout (ignoring the decimal period).
So the reading in binary would be as follows:
1436 - 101100111*00 *
1439 - 101100111*11*
2757 - 101011000*101*
2760 - 101011001*000*

Notice that the last two or three bits are different between those two numbers. The second set of numbers is interesting. I have one scale that tends to flicker the last three bits, but I've only seen it go between ...111 and ...000. I think yours might be jumping the last two bits, and the second set of numbers has some offset in TouchDRO so you ended with 101 and 000. 

The scales have a native resolution of a tad less than 10 microns (10 microns would be 2540 CPI, iGaging scales are 2650 CPI). This means that each increment is about 0.00039". I don't want to bore you with how to convert binary to decimal, but  1 in binary equals 1 in decimal 11 in binary equals 3 (2+1) in decimal, and 111 equals 7 (4+2+1). With the last two bits, your scale is jumping by 3 "ticks" or about 0.0013". If it's the last 3 bits, then your jumps are 0.0027.

EZ-View display averages 8 or 16 values for each position refresh, so you are not seeing this when the scale is connected to it. I don't know if this is OK for the type of work you do on your mill, but I wouldn't be comfortable with this scale. 

Hope this makes sense
Yuriy


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## ycroosh (May 9, 2021)

Kevin, you successfully "nerd-sniped" me to dig through my box of problematic scales and find one that has the same behavior as yours. I made an animated .gif of a series of oscilloscope screen captures that show this in action. In this particular case, the scale was plugged into its original display and was completely stationary. I did this on my kitchen counter, away from any machinery, running motors, etc. Second .gif shows a more common flickering of a single bit that would result in jumps by 0.0004" or 0.01mm. That one is an older DigiMag scale plugged into its original display too. Curiously, in both cases, the iGaging displays were completely still.


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## markba633csi (May 9, 2021)

The clock is the yellow right? Why so different between the two cases?
Is that expected?
-Mark


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## ycroosh (May 9, 2021)

markba633csi said:


> The clock is the yellow right? Why so different between the two cases?
> They must be using some type of clock multiplier since I see falling edge jitter on the second case- I don't know what's going on with the first one
> -Mark


Mark,
iGaging is constantly tweaking their scales, so I see a lot of differences between different scale and display revisions. Some early display units had a 50Hz refresh rate with equally spaced data packets. The latest EZ-View runs four bursts of 16 closely spaced packets with a much faster clock speed.
Regards
Yuriy


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## kb58 (May 10, 2021)

I don't own one of these units, and don't know Yuriy, but I do have a background in electrical engineering and software. Everything he's saying is exactly correct. I don't see anything in his responses that is exaggerated or played down; he's just stating facts. He has no control over whatever signal processing is done upstream of his product. It's just the nature of any digital-based sensor, that there will always be a potential one LSB (Least Significant Digit) bobble.

There's the scale itself, a sensor, and possibly inboard signal processing. The key thing to understand is how digital values are handled. If the sensor sees a scale reading of 1.999999", it will be outputting a reading of 1.999. If the sensor in the scale sees a shift of only one millionth of an inch, the output will change to 2.000. So, to the user, it may appear that the reading is "jumping all over the place", when in fact it's only changing by one millionth of an inch. That said, if it's jumping far more, then as Yuriy suggests, that may be due to a problem within the sensor assembly itself. The easy way to find out is to swap the X and Y sensor cables on the display to see if the problem follows the sensor, or doesn't. That's the "divide and conquer" method of troubleshooting.


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## ErichKeane (May 10, 2021)

kb58 said:


> I don't own one of these units, and don't know Yuriy, but I do have a background in electrical engineering and software. Everything he's saying is exactly correct. I don't see anything in his responses that is exaggerated or played down; he's just stating facts. He has no control over whatever signal processing is done upstream of his product. It's just the nature of any digital-based sensor, that there will always be a potential one LSB (Least Significant Digit) bobble.
> 
> There's the scale itself, a sensor, and possibly inboard signal processing. The key thing to understand is how digital values are handled. If the sensor sees a scale reading of 1.999999", it will be outputting a reading of 1.999 to the display. If the sensor in the scale sees a shift of only one millionth of an inch, the output will change to 2.000. So, to the user, it may appear that the reading is "jumping all over the place", when in fact it's only changing by one millionth of an inch. That said, if it's jumping far more, then as Yuriy suggests, that may be due to a problem within the sensor assembly itself. The easy way to find out is to swap the X and Y sensor cables on the display to see if the problem follows the sensor, or doesn't. That's the "divide and conquer" method of troubleshooting.


Yep, I also agree, though as a software engineer (though one who hooked up his ebay-scales to an O-scope at one point).  The signal that the scales send is noisy!  

That said, it seems above the OP mentioned that the range is actually about 3 thou.  I could definitely imagine that his scale is interpolating pretty poorly (as mine are :/), but a 3 thou jump seems bad.


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## kevinismo (May 10, 2021)

If I'm going to be replacing the scale, I don't see a point in keeping the thing. This was supposed to be easy and instead I have never been this frustrated my whole life. With the time and money I wasted on it the TouchDRO is still not working and jumping all over the place. I don't even see a point of TouchDRO if it can't display the position from the scale. What's the big idea? I don't care about touch screen or the features. I just need to see where my spindle is. Unless someone convinces me that it has some redeeming qualities, I'm going to chuck it into the bin and get a real DRO with real support that can read real scales.
Kev.


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## ErichKeane (May 10, 2021)

kevinismo said:


> If I'm going to be replacing the scale, I don't see a point in keeping the thing. This was supposed to be easy and instead I have never been this frustrated my whole life. With the time and money I wasted on it the TouchDRO is still not working and jumping all over the place. I don't even see a point of TouchDRO if it can't display the position from the scale. What's the big idea? I don't care about touch screen or the features. I just need to see where my spindle is. Unless someone convinces me that it has some redeeming qualities, I'm going to chuck it into the bin and get a real DRO with real support that can read real scales.
> Kev.



The problem you have is likely just what you get out of a poor-resolution scale, I think that is just about it.  I don't know anything about the  TouchDRO, but I'd imagine you would have the same problem with a "Real DRO", though the scales might have a better resolution (and thus do it at a lower amount of 'movement').


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## tonydi (May 11, 2021)

So let me see if I have this straight, *Kev*.  Yuriy spends a long time trying to help you, going way above and beyond the call in offering all sorts of ways to determine the problem.  He finally proves that it's not his product, but your scale, that particular scale.  

Yet you end up bad mouthing his product anyway and now you're taking your ball and going home.  Sounds like a win for Yuriy and now you'll be someone else's problem customer.


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