Re: [CAD_CAM_EDM_DRO] Re: Position counter stop updating....

riet91 wrote:

> Hi Jon & forum
>
> I was out of city while my friend Asim (with yahoo id lti_cnc)had
> post a message on this forum regarding
> stopping of position counters.
> > What speed of CPU are you using?
> We are using Pentium-II with 400 MHz cpu clock.
> > When the counters stop counting, do
> > you see a following error box pop up on the screen? Does it go into
> > estop-off mode from machine on? (See below)
>
> No we dont see any dialog box poping up!
> When we are joging any axis, The counters stop without poping up any
> window. while the joging is still in progress
>
> I have figured it out that Position counter sometimes dont update
> even at slower speeds. they just dont count!
> Sometimes after closing and restaring the tk-emc the counters start
> counting but as soon as the drives run at high speeds they stuck!

Due to noise in the original STG board (or the chips on it), there was a
piece of code added to the chain of routines involved in encoder reading
to suppress wildly invalid readings. If a very rapid change in position
is detected, it can lock up the display, as it believes no valid readings
are coming in, and will wait forever for a reading to be within some
range of the last valid reading. I forget the exact module this piece
of code is in. If your encoders have very high resolution, or the servo
update rate is set very low, this can be the cause. What is the servo cycle
time? It should be something like 0.001 for 1 mS = 1000 times/second.

Jon