For what it is worth, this is a snippet from my configs as to how I do
the same on my lathe (the other components are used elsewhere)
# **** Use ACTUAL spindle velocity from spindle encoder
# **** spindle-velocity is signed so we use absolute component to remove
sign
# **** ACTUAL velocity is in RPS not RPM so we scale it.
addf scale.1 servo-thread
addf scale.2 servo-thread
addf abs.1 servo-thread
addf abs.2 servo-thread
loadrt lowpass count=1
addf lowpass.0 servo-thread
setp lowpass.0.gain 0.01
##########################################################################################
# Display spindle speed in pyvcp bar
##########################################################################################
setp scale.1.gain 60.0 #convert velocity per sec into rpm
net spindle-velocity => lowpass.0.in
net filtered-spindle-velocity <= lowpass.0.out => abs.1.in
net absolute-spindle-velocity <= abs.1.out => scale.1.in
net scaled-spindle-velocity <= scale.1.out => pyvcp.spindle-speed
I do not use spindle-at-speed.
It is an absolute pain unless you have a high mass spindle or an actual
physical encoder rather than just an index pulse from a pickup.
The fudge factor you have to program in to prevent program pauses due to
speed fluctuations, makes it irrelevant.
I just command a 4 second pause after M3, which is enough to get to
speed and stabilise on my machine.
regards
On 04/01/17 08:48, Russell Gower wrote:
Hi Marius,
The examples in the documentation (all be it the upstream documentation, but
I didn’t think we would have diverged much in this area) had it at 0.01 as do
all the example configs i’ve found whilst googling - I have also tried setting
it to 1.0 which had the same out come.
Regards
Russell
On 4 Jan 2017, at 06:31, Marius Alksnys <[email protected]> wrote:
Isn't your lowpass gain higher than 1 ?
01/03/2017 09:31 PM, Russell Gower rašė:
Hi,
I wonder if someone could help me diagnose an issue I have with trying
to use a low pass filter to stabilise the pyvcp spindle speed display in
Axis, I got the idea from
here http://linuxcnc.org/docs/html/examples/spindle.html
With the low pass filter in place the speed is displayed for a few
seconds then goes to “nan” and the following is output on the terminal I
launched machinekit from
Exception in Tkinter callback
Traceback (most recent call last):
File "/usr/lib/python2.7/lib-tk/Tkinter.py", line 1437, in __call__
return self.func(*args)
File "/usr/lib/python2.7/lib-tk/Tkinter.py", line 498, in callit
func(*args)
File "/usr/lib/python2.7/dist-packages/vcpparse.py", line 154, in updater
a.update(pycomp)
File "/usr/lib/python2.7/dist-packages/pyvcp_widgets.py", line 1219,
in update
end, self.bh-1)
File "/usr/lib/python2.7/lib-tk/Tkinter.py", line 2205, in coords
self.tk.call((self._w, 'coords') + args)))
ValueError: could not convert string to float: floating
If I remove the lowpass filter then the speed is displayed fine (apart
from the jitter).
My config files can be found here
https://github.com/russellgower/Lathe-Config.git
Thanks
Russell
--
website: http://www.machinekit.io blog: http://blog.machinekit.io github:
https://github.com/machinekit
--- You received this message because you are subscribed to the Google Groups
"Machinekit" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
Visit this group at https://groups.google.com/group/machinekit.
For more options, visit https://groups.google.com/d/optout.
--
website: http://www.machinekit.io blog: http://blog.machinekit.io github:
https://github.com/machinekit
---
You received this message because you are subscribed to the Google Groups "Machinekit" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
Visit this group at https://groups.google.com/group/machinekit.
For more options, visit https://groups.google.com/d/optout.
