Basic XY Screw Mapping - Geo Table

[TomKerekes]

Hi MadTooler,

I know I could use the current Geo Correction for now, but in the future I will not be able to also use the Geo Correction for work and part correction/alignments.

Both could theoretically be combined into one Correction Table. But I agree that might be complicated especially if at different grid spacings.

I think this is actually the most efficient. Once the tables are combined the data only needs to have one table applied to it.

It is also forcing me to burden the system with 245 x 245 instead of 245 x 2 (one for x and one for y).

Probably not a significant consideration.

I need to look back, but I think I would also need to change "m_MotionParams.MaxLinearLength" to match the 0.2" and recompile anyway.

I think that is correct.

[MadTooler]

Tom,

Happy New year, I hope!!

I am finally getting around to working through screw mapping. At the moment, I am figuring out my temporary mounts for an X then Y scale. I will use the same scale on one then remove it and do the other. With my setup, permanent install of scales on both is not really an option.

While I am getting the hardware worked out, did you have any more thoughts on geo correction table vs. kinematics and the best approach for basic screw mapping since last we chatted?

Thanks

[TomKerekes]

Hi MadTooler,

No new thoughts

[MadTooler]

Tom,

As long as I wired it up proper, I should be able to start looking at one axis of scale vs. screw measurements later today.

New projects and sooner than later needs to have a simple and clean geo correction table available for use in job specific alignments has made it necessary to take the kinematic approach. That means I will be diving into the code deeper and recompiling the project.

While I am thinking through the steps I will be needing to take, I was unclear if I can make the actuator code look at an external text file and read in the values at run time, or if I will need to have those values hard coded before compile.?

[TomKerekes]

You can read it at run time. Copy how the Geotable is loaded.

[MadTooler]

Excellent. I will see where this takes me...

[MadTooler]

Tom,

I have the scale functioning. I am now trying to setup a "dual loop" to command and measure. I looked around, but I cannot find a clear instruction on setting up a dual feedback loop with snapamp, brushed dc motors with encoders, and scales. However, I did see "bhurts" is currently doing something similar on cnczone and having a hard time: https://www.cnczone.com/forums/dynomoti ... scale.html

[MadTooler]

Tom,

Thinking about it, I think I will skip the dual loop since this is a temp scale installed only long enough to get my measurements. Instead, I wrote a short test that moves while looking for the scale values to be what I want. Then it will write out the values and go to the next point.

So far, I am finding the spring in the system is bouncing a single scale step/micron past the desired stop point after a short pause. Also, my X screw is not so bad overall, but I do know there are some weird points I will eventually find.

Curious, since I will need help working through some of this as I get the mapping worked out, do you think you will add the feature in the future?

Do look at the cnczone link I noted prior. It looks like Ben really has a situation and needs some guidance.

[TomKerekes]

Hi,

Thanks for pointing out that Thread somehow I wasn't getting notified.

If it turns out useful we may want to add it as a new feature.

[MadTooler]

Should I be working with version 4.35f?

Regarding the measurements I am trying to collect, what will be better, to gather the position of the screw/motor encoder at the increments I have chosen then the true position from the scale, or move the screw/motor until reached the true scale position of the desired increments then gather the current motor position?