Re: relays

Hey,

http://sherline.com/emc/User_Handbook.pdf page 28+

I believe EMC was built to run closed loop servos with a motion
control card like the Servo To Go $888 ISA card.

Step/direction for steppers, step servos was an afterthought.
When using the parport with freqmod and minimill IO or Bridgeport IO
the pinout for the first parport is hardcoded into EMC for 6 axis
step/dir and home/limit switches. Pins that are commonly used for
aux. IO, 1, 14, 16 and 17 are reserved for axis B and C step/dir
signals. This unfortunately cannot be changed without modifying the
source code and recompiling EMC.

The .ini file does have settings for coolant, spindle, brake
etc... However, these settings only work for a second parport when
using bridgeport IO. So, you would need to have a second
parport/breakout to use aux. IO functions. I would recommend using
your Axxus board with it's relays on the second port, and use a
simple/cheap standard DB25 breakout;
http://www.winfordeng.com/products/brk25.php
on the first parport.

When your spindle started, what you saw is when the PC boots, some
outputs like 16 and 17 are forced high or lo. This can turn on
things connected when you don't want them to. However, you have no
control over these pins. This is exactly what the "charge pump" for
Mach 2 prevents, and is built in to the Campbell Designs board and
one of the PMDX boards.


You do have another option though. Since you already have geckos
servo or stepper (doesn't matter), check out Jon Elson's products at;
http://jelinux.pico-systems.com/motion.html

He has a USC (universal stepper controller) for $250 that does a
ton of things. It has a 300Khz hardware based pulse output, (much
faster than 30-45Khz from EMC or Mach2 with a fast computer), plenty
of IO capability, an e-stop watchdog circuit, encoder feedback to
software with steppers or servos, and 4 axis capability. It will
interface to Gecko servo drives or Gecko stepper drives. The cards
can also be daisy chained together, up to 8 I think. All this is off
of one parport. Plus, the driver is already built in to EMC, and Jon
Elson is very helpful.

I plan to use this card or the similar PWM card and PWM servo
drives, with a future project with EMC. I'm currently working on a
lathe, since EMC has no lathe functionality, and especially no
threading capability, I went with Mach2 this time.

EMC is awesome, with the right hardware. However, it's lack of
pinout configuration when using a single parport hurts it badly.
EMC2, not available yet, is addressing this and many other issues
that will greatly improve it.

If you want to use EMC, I would seriously look at Jon Elson's USC
board. If you can't spend any more money, with your current
hardware, you will have much better luck with Mach2 or equivalent.

Good luck.

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Gene <capper@i...> wrote:
> I have a axxux tech. breakout board and two relays hooked to pin 14
and
> pin 17. I am using EMC with geckos. I cant figure how to control the
> relays with software. is this possible? for a while the spindle
would
> start as soon as I turned on the power to the geckos, but now there
is
> no power to the relays at all. I don't have any idea what i did to
make
> this change. any help would be appreciated.