Measure Step Loss between two machine homings?

[mr_cg]

Hallo!

I am new to UCCNC and i am trying to find a way to measure potential step losses between two machine homings.
This basic feature is available in Estlcam and WinPC-NC but i could not find it in UCCNC.

How is it possible to measure potential step losses in UCCNC?

Thanks for support!
Br
Christian

[Vmax549]

Do a site search on " Verify Function " and you should find it.

(;-) TP

[dezsoe]

Hi Christian,

You can find a macro in this post. Use M20910 if you use the 1.2049 stable version.

[mr_cg]

@ dezsoe
Thanks for your answer about M20910 but unfortunately it's not what i was searching for.
Sequence should be as follows:
1. Home all machine positions (X, Y, Z) at the beginning
2. I perform my CNC milling actions e.g. 1-2h of milling
3. At the end i want to know if there was any step loss while all my activities. I perform another homing on all machine positions (like 1.) and from this i want to know the deviation (=step loss) to the initial machine position homing.

This is useful to get confirmation that final part is 100% ok and it also provides very good indication about the machine reliability.
It was a basis feature in Estlcam and WinPC-NC and i wonder how this is possible in UCCNC.

E.g. in Estlcam i automatically get this information if machine axis homing was done a second time.
For better understanding about what i mean here the information as example which i get as feedback in Estlcam after second machine axis homing:

Code: Select all

Position Deviation:
X:  0 steps /  0.00mm
Y: -1 speps / -0.01mm
Z:  2 steps /  0.02mm

[dezsoe]

Did you try the macro? That is exactly what it does. You home your machine, do test or work moves, then call M20910. The macro homes the machine without resetting the axes and writes the difference in units and steps.

[mr_cg]

Yes, i have tried M20910 but it's only doing this for z axis. I have Stepcraft 2/840.
It is not moving/homing the x and y axis.

Feedback from M20910 looks like this:

Softlimit reached;
Z axis: 0.015, 1.9999995 step(s)

1. So first issue is that is is only testing the z axis.

2. Second problem is that speed is to fast which lead to step loss because the axis is mechanically hitting the end point. Same issue also in WinPC-NC.
From Estlcam i know that machine axis homing needs to be done very slow on Stepcraft machines in order to get reliable step loss results.
The electrial switching point on Stepcraft is quite close to the mechanical end stop (hitting the aluminium end stop) which does not allow normal speed for this activity.
I guess the homing speed can be easily adapted in M20910 macro. Can you point me to the right line of code?

Thanks

[dezsoe]

The homing speed is not set in the macro, it uses the speed you have set in the axis setup without any change. This macro checks the homing only on the axes that are set in the home sequence on the general settings page. It reads the home sequence and calls the home check in the order of the set sequence. If an axis has no home pin set then it will not test it. So, you have to check your home speeds and the homing sequence. (The macro makes a normal homing except that it turns off the Auto set checkbox, so it can calculate the difference between the current and the normal homing.)

[mr_cg]

The homing speed is not number one priority at the moment because first i need to get M20910 working at all.

The homing sequence is set like this and the normal machine homing is also working without any issues for X, Y and Z:
1. Z axis
2. X axis
3. Y axis
4. none
5. none
6. none

All axis have home PIN configured. For stepcraft all axis are using the same PIN but this should not cause any impact to the homing procedure.
The issue with the M20910 macro on Stepcraft seems to be that "softlimit reached;" is caused by initial z axis homing and the macro exits without doing the job for X and Y.
I guess the M20910 macro need to be able to handle or prevent exiting if softlimit is reached. Also for the normal machine homing it is not causing any issue.
I believe the M20910 is not working on any Stepcraft machine because of this.

When disabling the "Enable Softlimits" in the general setting than M20910 is working.
But in general i want to use the softlimit protection. How to disable the softlimit feature only in the M20910 macro?

[dezsoe]

I modified the macro to disable and after checking reenable soft limits.

[mr_cg]

I have further investigated and i am quite close to get reliable homing results on Stepcraft in range of only 0-2 steps deviation which is totally acceptable.
For productive work i have the following questions to be clarified:

1. How to disable the "Enable Softswitch" only for the M20910? At the moment i am manually disabling the feature but this is not practical solution.

2. By reducing the homing speed for up/down and some macro modifications the home check for Z and X are already very reliable.
Unfortunately there seem to be different homing implementation in UCCNC (or even bug) for Y axis because here the deviation is always in the range of the backlash distance.
I have configured backlack for all three axis (XYZ) but only for the Y axis the home check difference is visible.
It could be possible that for the general home all axis function the backlash steps addition is done in different way (e.g. before or after reversing the down from switch movement).
This issue is 100% reproducable and the deviation is always on Y axis is almost same range than the backlash coniguration for this axis (Y backlash is 0.22mm, X backlash is 0.27mm, Z backlash is 0.11mm). See screenshot attached.

3. Is it possible to modify the code which is executed if regular "HOME ALL" button is pressed? How?

Many thanks for support. I really believe that lot of Stepcraft users should be interested in optimized and reliable check home feature.