Re: PPMC developments

[Fred Proctor <frederick.proctor-at-nist.gov>]

Jon Elson wrote:

> So, now EMC comes up on the system, but I can't get out of
> estop (sound familiar?)  I have a .ini file that works perfectly
> on the real EMC system with the Servo-to-Go card in it.
> Now, as I understand it, the sensing of estop is through the
> parallel port, not the STG card.  So, it seems like it should
> come out of estop without the STG card.  But, maybe there
> is additional logic in there that senses the STG card is missing,
> and forces it to stay e-stopped.

I'm always plagued by not being able to come out of estop. Several
things need to be true for you to be able to come out of estop. They
are:

1. The estop sense needs to show that the button/relay is not latched.
You can use ESTOP_SENSE_POLARITY to twiddle this, as you noted.

2. The motion system needs to be off the position limits. If the
hardware limit switches are tripped, you'll have to physically move the
axis off the limit switch, or change the polarity of the limit switch in
the .ini file (MAX/MIN_LIMIT_SWITCH_POLARITY).

3. The amp fault must not be asserted. If you don't have the amp fault
input tied to the real amp fault, then set FAULT_POLARITY to be such
that you don't see a fault when reading the stubbed value.

What I normally do when I can't come out of estop is bring up the EMC
motion diagnosics application "usrmot" and peek into the status. Once
the EMC is up, run usrmot (via "plat/linux_XXX/bin/usrmot -ini
yours.ini") and then show the status, with "show flags" and RETURN.
You'll see the bits labeled. Notice anything like amp fault or limits
that may keep the motion system from allowing you to come out of estop.
"show" with no args returns to normal status mode, where RETURN just
updates the status.

You can use emcpanel with the IO system to check its status. What I do
is run the emcio controller manually, by itself. It doesn't need motion
or the task controller to be up. Then, run the text-based emcpanel, with
"plat/linux_XXX/bin/emcpanel -ini yours.ini", and you'll see errors pop
up showing that it can't connect to the task level (it's not running),
and you'll get the emcio> prompt. You can type "estop on/off" and you
should see your electronics taking the system out of estop. If you can
come out of estop with emcio only, then the problem is with the motion
system. If you still can't, it's at least an IO problem.

--Fred