Unable to calibrate axises

[redvan22]

Just got a TouchDRO for my mill and after installation I am unable to calibrate each of the axises.

I followed the instructions from the website using two 1-2-3 blocks, setting the CPI to match the size of the block face (30000 for the 3" face) I was using and I get an odd reading on the DRO and when I input the value into the CPI and test to see if I get the right reading... I get a negative number nowhere near the size of the block face (3.0). I realize that the negative number could be because the direction I'm traveling in but I've tried this on each axis several times and just can't get the calibration right.

As I said I followed the instructions exactly.... https://www.touchdro.com/resources/getting-started/scale-calibration.html
AND watched a video...

Any help would be greatly appreciated.

Mike.

 

[RJSakowski]

What were the readouts that you got after moving the 3 inches?

 

[mchasal]

Just got a TouchDRO for my mill and after installation I am unable to calibrate each of the axises.

I followed the instructions from the website using two 1-2-3 blocks, setting the CPI to match the size of the block face (30000 for the 3" face

I think this is your problem, you don't set the CPI to 30000 in step 1 just because you're using a 123 block, you set it to 10000. You only use the size of the block (distance moved) when doing the calculation for the correction in step 3.

 

[ycroosh]

Just got a TouchDRO for my mill and after installation I am unable to calibrate each of the axises.

I followed the instructions from the website using two 1-2-3 blocks, setting the CPI to match the size of the block face (30000 for the 3" face) I was using and I get an odd reading on the DRO and when I input the value into the CPI and test to see if I get the right reading... I get a negative number nowhere near the size of the block face (3.0). I realize that the negative number could be because the direction I'm traveling in but I've tried this on each axis several times and just can't get the calibration right.

As I said I followed the instructions exactly.... https://www.touchdro.com/resources/getting-started/scale-calibration.html
AND watched a video...

Any help would be greatly appreciated.

Mike.

After the calibration, do you zero-out the axis? I.e. calibrate, move to one edge, zero out the axis, move the other edge and check the reading.

 

[redvan22]

I think this is your problem, you don't set the CPI to 30000 in step 1 just because you're using a 123 block, you set it to 10000. You only use the size of the block (distance moved) when doing the calculation for the correction in step 3.

mchasal,
I setup the 1-2-3- blocks again (long sided)
Zeroed the indicator on the X axis on the first block.
Set the X axis CPI to 10000.
Removed the first block traveled 3" and zeroed the indicator on the fixed block.
The number displayed was -1.5245
I first used this number as a whole (15245) for the CPI and the display read -1.4462
I then divided -1.5245 by 12 and got 1270.4166666 used that number (1270) and the display showed -0.2826
Tried using 12704 and the display read -0.2819

Tried again using 1" travel and the display showed -0.5092 and when I entered that whole number, display showed -0.7284

ycroosch,
According to the video, once the CPI is updated, the correct distance traveled should be shown on the display, 3.0000.

Also, every time I go into Settings, I lose the connection and after making settings changes, I need to wait for the tablet to reconnect. Could this have some bearing on the issue?

 

[mchasal]

mchasal,
I then divided -1.5245 by 12 and got 1270.4166666 used that number (1270) and the display showed -0.2826
Tried using 12704 and the display read -0.2819

Why are you dividing by 12? From the instructions: "Divide the reading (ignoring the decimal point) by the number of inches traveled." You might want to carefully read through the instructions again.
ETA: I see now where you got the 12. That was just an example. In your case, it's 3 since that's how far you traveled.

So your CPI math should be 15245/3 = 5081.6...

Try setting the CPI to 5082 and see if that gets you sane results. (You do not ignore the decimal point in this step!)

If you're still having trouble can you take a video of your whole process and share it and maybe we can see what you're doing wrong?

 

[redvan22]

Ok,
Repeated my steps on the X axis.
123 block clamped down.
Placed another 123 block next to it long ways and zeroed the DI.
Removed the block and zeroed the DI on the clamped block.
The reading was 1.5240 / 3 = 5080
Entered 5080 for the CPI and the display showed 2.7402

 

[redvan22]

Please correct me if I'm wrong; the ABS values for all axis should be zero before calibrating?

Now, I re-did the calibration on each axis (after setting the ABS values all to zero and following the instructions carefully) using the 3" side (except for the Y axis where I had to use the 2" side) and what I saw in the video didn't happen for me but after entering the calculated value from the displayed value, I got an unexpected number (at this point in the video, the display showed the actual traveled distance) so I thought, I'll zero out and return to my point of origin and insert the block to see what happens. So I zeroed and then moved the amount of travel until the display showed the correct value (3") and reinserted the removed block and the DI came to zero (actually a few tenths more or less)

So, does all this sound like I finally calibrated the axis correctly?

 

[mchasal]

Please correct me if I'm wrong; the ABS values for all axis should be zero before calibrating?

Zero or not shouldn't matter. All you're doing is counting the number of steps per inch. Starting from 0 just makes the math a little easier.
See Yuri's correction below.

I'd say if you're getting 3" of travel on the DRO when you move the table 3", you're dialed in.

 

[ycroosh]

Zero or not shouldn't matter. All you're doing is counting the number of steps per inch. Starting from 0 just makes the math a little easier.

I'd say if you're getting 3" of travel on the DRO when you move the table 3", you're dialed in.

Checking the calibration from zero is very important here. This is the most common mistake with calibration.
What happens is that TouchDRO has two offsets that it keeps internally: one from the scale zero to the absolute origin and another from absolute origin to incremental origin. Those are stored in microns. When you calibrate the scales, you change the ratio between scale encoder increments and microns, so the offsets change. This is why is VERY important to check the calibration from 0, as redvan22 did above.