Re: EMC running at last!

Clint Bach wrote:

> From: Clint Bach <clintbach@...>
>
> It has been a long and hard battle with rtlinux and emc but I may have
> finally won the battle! The trick seems to be (for me!) to copy rtlinux
> and linux both to /usr/src. Symbolic links would not work for me
> somehow. I know not why.
>
> I have one last hurdle (or maybe only a few more hurdles!). I do not
> have the computer hooked up to an actual machine yet and I can't get the
> estop to reset. I presume the system thinks I have hit a limit switch
> or something. The axis fonts are red... Not the green of a ready to go
> system. I presume there is a place to tell the program how to behave
> but I don't know where that is. I would guess in the emc.ini file.

The limit switch polarity is indeed in the emc.ini file, and the method of
selecting polarity is quite obvious by the names of the parameters.

But, that won't lock you in estop - there is an e-stop signal required
from the motion hardware. If you look at the schematic of the E-stop
external hardware I use at http://www.artsci.wustl.edu/~jmelson/EMC.html
You'll see that this hardware provides an e-stop signal at pin 25 of a
26-pin IDC ribbon cable connector. That maps out to pin 13 of the
traditional D-25 connector that plugs into the parallel port.
This signal indicates an external fault or E-stop condition when high, or
left unconnected. grounding pin 13 of the parallel port should enable
EMC to be brought out of E-stop. You could just wire a normally
closed emergency stop button to ground this pin when not pushed,
if there won't be any other E-stop conditions.

The additional circuitry in that schematic watches the fault chain from
the servo amps, and also the watchdog timer on the STG card, and
not only informs EMC of the condition, but also kills power to the
auxilliary controls, like spindle and coolant.

Jon