View Full Version : spindle speed display in gmoccapy under reading by a factor of 1000

02-12-2020, 01:21 AM
getting into the final stages of linuxcnc configuration on my Boxford VMC190 - its been quiet a journey of discovery, but got there with lots of reading, some help from great people on here and some trial and error.
The last issue was to get spindle speed feedback from an optical sensor reading one pulse per rev back into Linuxcnc
I have got this to work, kind of, but the speed is reading about 1/1000 of what it actually is doing i.e. an actual spindle speed of say 2000RPM (estimated by eye only) is displaying a spindle speed in Linuxcnc of 20

I'm thinking some sort of scaling is needed to bring the displayed value from 20 to 2000

I will grab the latest config files (ini / hal's etc) from the PC and post them tomorrow


02-12-2020, 01:27 AM
2000/20 = 1/100

Need Configs. Likely you have your encoder scale set wrong.

02-12-2020, 01:06 PM
Just another thought seeing as you're largely eyeballing this - there's no weird stuff going on between PPS and RPM is there (x60 scaling) - I don't have my HAL to hand (and it's moved on since then) but pretty sure at some point I did use a 60x scaler.

02-12-2020, 01:44 PM
IIRC, you are using parallel port, not a Mesa board?

02-12-2020, 11:58 PM
sorry all been busy with work and too cold to go into the workshop now to get the ini/hal files
to answer what I can without the files
using a pair of Par ports
I can't be sure what actual speed the spindle is running at, but it does 'feel' to be out by a factor of 100 (not a 1000 as I orignally stated, typo) however I have just remembered I bought some years ago a display / promimity sensor and magnet that runs from 12 volts. I had it on my Boxford BUD before converting it to CNC at which point it was removed and but back in its box, I'm 99% I know where it is so can use that to double check the actual spindle speed

I will try to post the ini / hal files sometime tomorrow

thank all

03-12-2020, 06:12 AM
I didn't read the bit about estimating by eye.

The revs per sec (RPS) vs revs per min (rpm) would be the most common error. 60x out.

03-12-2020, 10:31 PM
files attached

05-12-2020, 10:08 PM

Got it sorted the other day just needed to adust the scalling
I have attached the files again just in case this helps anyone in the future who stumbles upon this thread

I've been practicing milling Hex and Sq on some bits of ally bar ends using the A axis. The accuracy is astounding, well under 0.0005"
very happy with my Boxford VMC190

for a cheap conversion to Linuxcnc using a pair of Par ports and two 6 BoB's I have 4 axis control, spindle control, XYZ axis jog on the Boxford control panel and Start Stop Step, tool change all also on the Boxford control panel, plus a Wifi pendent which replicates all of the control panel function using an MPG and a host of useful macro keys
Probing is also now fully working,

Next job is coolant