Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: Hix on February 28, 2018, 05:15:39 AM

Title: Spindle Index anomaly [Hall effect - last stored RPM]
Post by: Hix on February 28, 2018, 05:15:39 AM
Hi Folks,

Just joined. I've got a Taig Mill which I'm running using Mach3 through a Gecko G540.
I recently updated the motor in the mill to a Brushless servo motor. As part of the upgrade, I can now use Mach3 to control the spindle speed.
Here's where I've encountered something weird.
I added a magnet to the spindle and used a Unipolar [non-latching] hall effect switch to measure RPM at the spindle. All works well, however, when I stop the spindle the RPM value in Mach3 retains the last seen RPMs. Does anyone have any ideas on what could be going on here? I've checked with a DMM and the HE switch activates in the presence of a magnet, and goes back to VCC when the flux field is far enough away.
It's not a massive issue, but it is bugging me, it is also causing problems calibrating the spindle, as that starts from 0, which is never 0.
Cheers
Title: Re: Spindle Index anomaly [Hall effect - last stored RPM]
Post by: joeaverage on February 28, 2018, 05:30:48 AM
Hi,
I'm guessing what happens is that when you stop the spindle (M5) the spindle speed DRO stops updating and just sits there displaying its last known value.

Try this, insteadi of stopping the spindle issue a speed command of zero, wait for 5 seconds or so for the spindle to reach its new programmed speed (0)
THEN issue M5.


S 0
G04 P5
M05

Craig
Title: Re: Spindle Index anomaly [Hall effect - last stored RPM]
Post by: Hix on February 28, 2018, 05:44:35 AM
Cheers, I'll give that a spin.
However, it would be good to get to the bottom of why the DRO just retains the last seen value.
Title: Re: Spindle Index anomaly [Hall effect - last stored RPM]
Post by: joeaverage on February 28, 2018, 05:52:10 AM
Hi,
it stops updating because you told it to, that's part of what M5 does.

Craig