Gunner Asch wrote:

On Sun, 27 Jun 2010 11:30:44 -0500, Ignoramus12901
wrote:

On 2010-06-27, Pete C. wrote:

"Pete C." wrote:

Ignoramus11285 wrote:

On 2010-06-26, Pete C. wrote:
Ignoramus31989 wrote:
On 2010-06-26, Karl Townsend wrote:
9. Pot for axis feed rate. change feed while running program.

nope

Most "real" machines don't have this either. What they do typically have
is a rotary switch providing feed rate override capability in 10% steps
+/- some decent range. This allows the machine operator to tweak the
feed rates to match the real world cutting conditions, slightly dulling
tools, etc. vs. the ideal conditions the person who generated the G-code
wrote it for.

I can do that from keyboard, it seems more industrial in nature.

Yes, as a HSM guy, you don't need quite the same programmer vs. operator
setup.


12. six limit switches

got only five

That is sufficient generally. The control doesn't really have to know
which direction the overtravel was, as long as you can hold the
momentary limit override toggle switch and manually jog the axis back
off the limit. This is how most real machines operate. Many have three
limit LEDs next to the limit override toggle switch to show which axis
is on a limit as it can sometimes be difficult to tell if more than one
axis is at the end of travel.

But this means that, for homing with limit switches, theq limit
switches should not automatically inhibit drives via the inhibit
function, right? At least on my Y axis with only one limit switch?
And so, EMC should be responsible for proper behavior when limits are
reached. Right?

Yes, and no. You can actually have it both ways, since you're a
programmer. Your limits can connect directly to the servo inhibits and
you can have your "limit override" momentary toggle switch actually
disconnect and override the inhibit signals to the servos (use a 4 pole
switch). That way you still have true hard limits even if EMC goes nuts
for some reason, and the real ability to override the hard limits to
manually jog the axis back off the limits. The three LEDs limit LEDs
should be able to be directly driven from the inhibit signals to the
servos.

Forgot to add: If you need to move off limits under EMC control, as in
for a homing process, you can use an output from EMC to operate a relay
(4 pole) in series with the limit override toggle switch, to allow the
control to override limits during homing.

That's smart, looks like a way to go.

I think that hitting a limit, as such, is not a disaster if it is
handled right. So I would not want a limit to do a full estop.

I am really not sure what I want at this point, what is the ideal
estop behavior and what EMC can do with estop signals. Maybe I will
ask on the EMC forums.

i

Typically...there are two switches on each axis end. The first one is
for a warning/control change..the other is a home switch

When you run into the first switch..it signals the control that it
NEEDS to slow down and now..and after it does..it gently approaches the
home switch and stops where its supposed to, rather than slamming into
the hard stops as it overtravels beyond the home switch while
desperately trying to slow down.

I've not seen decel switches on both ends of an axis, perhaps that's
normal on some of the faster machines. The machines I've seen have a
decel switch only on the homing end of the axis, and the homes and
limits are both roller limit switches and trip rams that so that the
limit trip point is somewhat before the physical axis limit so the axis
can safely travel a little past the limit trip if it was moving fast. In
one of the previous threads I gave the detailed homing procedure using
the encoder index and why it's used.