Axis_Comp having no effect[SOLVED]

I'm trying to axis comp a machine with a Renishaw ML10 Interferometer. Unfortunately no matter what comp type or file formatting I can come up with I cannot get the system to take effect. The machine is repeating +/- .001mm on every step of the run.

I've been working on this for days and had no luck. I also can't get any feedback from HALSHOW that mentions it in effect or a component related to compensation. My understanding this a rolling backlash table to linuxcnc, hower the values never change. The man pages are extremely sparse, but strait forward. Name a file, stuff it with (Target)  (POS Move) (Neg Move) and select a type 0 or 1.

Please help! I offer cookies of all types.

Also of note the units in the RTL File are um so .001mm. Pass 1 is -5 to -170 and Pass 2 is -170 to -5.

The .zip is a zipped .xls file.

 
 

Just a guess, but I think your screw compensation table is backwards:

"Compensation files must start with the smallest nominal and be in ascending order to the largest value of nominals"


 

If the comp table is backwards then the interpolator function will only ever read the first value, so you will get a fixed offset, and no apparent compensation.

I'm happy to say, I was just being dumb and -5  was lowest number in my head except it was negative so it was obviously the highest number.  I also spent a bit of time playing with spreadsheets and the raw RTL file and it was easy make a mistake shuffling data.

So, I wrote a python script to handle the process. (I haven't tested it with an axis going in the positive direction, it should work.) 
  Renishaw_Laser10_with_LinuxCNC

I really hope it helps someone someday.  I've attached my results before and after.

Good to see you have comp working.
The raw error looks very linear, are you sure about your Exp coeff value?

Yes, it’s a rolled screw it has error from the manufacturing process. Thomson claims +\- 0.004 per ft / 300mm.

Though it could be mathed out in the SPU if I was using UCCNC or MASSO.

I did most of my work on big iron. Watching what happens with an AC vent hitting the top of a machine with a laser will drive you crazy.
Good luck!

scotth wrote:

 Watching what happens with an AC vent hitting the top of a machine with a laser will drive you crazy.
 

Skunkworks implemented temperature compensation on his (large) mill a long time ago. 



 

This is very cool, I have a customer who created cooling passages and plumbed a chiller into his spindle motor mount. Then ran it into spindle motor to keep it from growing.