Limiting Resolution

If you can edit glcanon.py a PyVCP panel is simple...

JT

I'm sure I could figure out the panel, just haven't taken the time to do it yet. Do you think there is any advantage to making a panel? All I can think of is adding both commanded position and actual position to get a feel of how the mill is performing real time.

Todd Zuercher wrote: I must say I've never seen a machine that could achieve such precision, in reality most are lucky to be +-.01mm.

You can achieve that sort of resolution with a good lathe.

(This isn't my picture, but is the lathe of a chap who first prompted me to look at adding extra decimals to Axis)

picasaweb.google.com/1081645046564043805...#5952917901014508418

Every diameter is X.000mm on his micrometer, you can see he is using high resolution scales on the X axis.

The main advantage I can think of is the next time there is a Linuxcnc update and you install it, you would not have to redo your changes you made to Axis.

I wasn't saying that machines that good aren't out there, just that a lot of people are fooling them selves because the DRO might have X number of decimal places.

Todd Zuercher wrote: The main advantage I can think of is the next time there is a Linuxcnc update and you install it, you would not have to redo your changes you made to Axis..

It ought to be fairly easy to add a DRO_FORMAT entry to the INI, and have the UI's look for that. Though currently glcanon.py does not know how to look at INI files, and might not always have an INI file to look at.

perra_e wrote: I have configured my servos so they give 10000 lines (or 40000 pulses) per turn to my Mesa 7i77 board for a 5mm screw. That is a resolution of 0.000125mm. This will produce a 2Mhz signal at 3000rpm wich is maximum speed in my setup.
I have only dry run this since I have not got my mill yet due to some delays, but without any load it works fantastic well.
After some adjustment of the PID there is about 0.005mm following error at 2000 mm/min if i have interpred halscope correct.
It shall be interesting to se if I can use this in reality as well.

Hi

I figth with setting while made my analog servo setup with mesa 7i77. What a hack set to encoder output resolution? I am using delta servo packs which have conficurable output resolution. Do i set 1000, 2000, 4000 or what pulses/rev?

Linuxcnc servo period is set to basic setting 1khz. So position is read from mesa and second velocity calculation is made 1000 times per second am i right?

so if i change delta servo pack output resolution from 1000 pulses into 2000pulses/rev so my position location accurasy is doubled? But position is stil read/updated from mesa card 1000 (1kHz) times per second (servo period time)

Max encoder communication rate between Delta servo pack and mesa 7i77 is about 2Mhz?

So if i like to make all as fast and accurate:
-i decide max needed system velocity m/min.
-i devide mesa 7i77 Max count rate 2MHz with max velocity to get maximum resolution which can be used in max velovity.
- i pump servo period time as low as computer stability allows. Smaller period time gives higher position reading and velocity calculation update rate (kHz).

How about base period time? Is there no need for that? analog servo system is not making any pulse stream.

If you are using a 7i77 then you don't need a base thread and should disable it.