On 2010-07-22, Jon Elson wrote:
Ignoramus24043 wrote:

What happens is that if I approach home slowly, the home switch
triggers, but since the table stops instantly, it untriggers.
You may have oil in the switches. Now that you are using it, it may
clear up after a while. (or, it may get bad enough you will need to
eventually replace the switches. Watch during homing for it to ignore
the switch and just keep moving.)

I think that you got it.

The resistance that I measured, was kind of high for a closed
switch.

If the
table moves fast, it takes it some distance to stop (1mm?) and by that
time, the switch is fully actuated. Homing fast is what I want,
anyway.

The question I have is how fast should I be in my index-finding move
(latching move).
Although the latest incarnation of the PPMC does this all in hardware at
10 MHz speed, it seems prudent that you shouldn't be moving more than 1
encoder count per servo cycle, or typically 1000 counts/second. But, in
fact, it doesn't matter, as the encoder counter is zeroed in hardware
when the index pulse is detected and the zero-count-on-index logic is
enabled.

I have upped the speeds a little bit, and made all axes home at
once. Now the homing part is really quick. The last part of homing
involves getting the middle of the table approximately under the
quill, for convenience.