Accumulated travel distance for axes

I have tried to figure out if it is possible to accumulate the distance the axes are moving.
I have a reccomended service interval (lubrication) of 2km for my mill and it would be very nice to get this information out of the mill instead of guessing!

Has any one done somthing like this?
If it is not possible, I'm interested in adding this feature to Linuxcnc.
I guess that I'm not the only one that would like this.

--Per

What kind of axis do you have?
This might be pretty easy for a software stepped system. (In other words I think I have an idea that may work.)
A hardware stepper or servo may require more thought, but should still be possible. (In other words, I don't have an idea how to do this, yet.)

Unfortunately I have analog servos with Mesa 7i77 interface. So we are in the "don't have an idea yet" territory
I'm absolutely willing to try to develop this if I get a hint where to start!.

--Per

Ok I think I have another idea that should work for all situations, but it may not be the best or cleanest way to do it. and I don't quite have all the pieces of the puzzle. (hopefully if someone has a better idea they'll chime in.)

There are 3 key steps to making this work, 1st getting the absolute distance traveled, 2nd remembering the distanced traveled between Linuxcnc sessions and restarts, and 3rd triggering your warning, or lube cycle at the required maintenance interval.
Here is a rough sketch of the hal work to implement the 1st step for one axis.
1st step, using the abs component connect the axis.N.joint-vel-cmd pin to the input of an integ component. The output of the integ component would be the total distance traveled since starting the machine (or since the last reset of it)

I'm not sure about how to implement the 2nd step.

The 3rd step seems simple enough, so I won't go into it now

Fantastik, it works ! This was the hard part for me!

If there is no ready hal component that can save the result it should not be too hard to write one that saves the distance to a file. It can be triggerd when axis.n.amp-enable-out goes low for instance. and at the same time reset the integ component.
Spontaniusly I Think of the following pinns:
in1 - actual Count ( from integ). Or even better, do the abs and integ inside the component and just connect axis.n.joint-vel-cmd
in2 - Trigger for write to file
out1 - reset integ (if not internal)
out2 - Total Count (saved + actual Count)
out3 - Alarm service distance.

param in 1 - Distance for service alarm

This was exciting! I will start with this tonight.

--Per

One neat thing about the integ component is you could input the stored distance value to the integ.N.min pin and that would set the integ.N.out startup value. But you might have to work out how to reset it back to 0 when you need to restart your count.

Maybe this would be helpful for the hal pin persistence?
wiki.linuxcnc.org/cgi-bin/wiki.pl?Contri...ents#Parameter_Saver