"Ignoramus31989" wrote in message
...
On 2010-06-25, Karl Townsend wrote:

"Ignoramus31989" wrote in message
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On a second thoughts, I was reading about PPMC on the linuxcnc
website. It would seem that PPMC includes this functionality already:
there is a relay on it that is switched off when estop is activated.

What this means is that I can wire the motive power contactor through
that relay in ppmc and it will do what I want: when estop is
activated, the motive power contactor drops out.

i

You got a pretty good plan there iggy. I'd suggest you also have a
machine
stop button. This stops motion and spindle through software (servo
inhibit
and VFD brake etc.). This is the normal everyday stop button. I also like
a
spindle stop button. Buttons are cheap. this assumes inputs aren't a
limiting issue in EMC. I know Mach 3 really limits you on inputs for this
sort of stuff.

Yes. On the machine itself, there are several buttons among many:

OK, thanks

1) E-Stop
2) Green START
3) Red STOP

So, I think that E-Stop should function, like you say, through the
estop input of PPMC and cut off all motion power.

The START should be a signal to EMC to start (resume) the process. The
STOP button should pause the milling program. The START button should
start, or resume, the program.

PPMC has 16 inputs. Of them, one is a E-Stop. So I have 15 inputs
left.

The first candidates for inputs are limit switches (6), Start/Stop
(2). This leaves 7 more digital inputs. Ideally, I would like to make
my X-Y-Z hand controls to work. For that, I would need at least 6
inputs.

I hope that if I need more buttons to work, I could expand this PPMC
by adding one more I/O cards.

I will make a separate post about limit switches.

i

Buttons I really like on my controls

1. Cycle start. that's your green button
2. Feed hold. red button - halts Gcode till you press cycle start again.
3. Single step switch. when on each cycle start runs one line of Gcode
4. optional stop switch - put an option stop M code in your program and it
will stop executing till you press cycle start.
5. spindle start. need to start spindle for edge find most often.
6. spindle stop.
7. machine stop. Put beside the estop and use this for nearly all stops.
8. Pot for spindle speed. change speed while running program
9. Pot for axis feed rate. change feed while running program.
10, Rotary Mode switch - three inputs. using base2, you can have handwheel
for all axis (four), jog, run, MDI (you can put single step on the mode
switch - line 3)
11. handweel increment switch. On for coarse, off for fine
12. six limit switches
13. three home switches
14 Nine Jog buttons in three rows of three. perimeter is X+,X-, Y+,Y-,
Z+,Z-, A+,A- center is rapid jog.

This is the sort of stuff you find on a Professional control. I'm spoilt -
I HATE using a keyboard as a substitute.

I'm sure you won't do all these, just stuff to think about.

Karl