Re: This is my same confusion (Port#2 re-visited)

[Ray Henry <rehenry-at-up.net>]

Patrick

Yep!  Some confusion is justified here.  You will probably find more of these 
when you get into lube and a few others.

On Tuesday 07 May 2002 01:16, you wrote:
<s>Please note below:
>
> ESTOP_SENSE_INDEX         =     1
>
> This means that S1 on this particular parallel port is an input, right?
>
> Ok, now observe this:
>
> SPINDLE_FORWARD_INDEX     =     1

In this case the (1) assigned to sense index refers to the first input pin 
and the spindle forward index refers to the first output pin but it is 
possible to assign the same pin to more than one variable. 

A number of folk have pointed out that the weakest part of the EMC is it's 
relationship to what the folk at NIST refer to as auxiliary I/O.    That is 
probably justified by the fact of their mandate which is a motion API.  Most 
of the I/O work done on the EMC has been related to motion rather than 
machine control. 

Fred Proctor is quoted in the handbook and the archives as saying that if 
someone held a gun to his head, he would write a Programmable Logic 
Controller using Tcl/Tk because that has the easiest connector into the NML 
language and communication channels that allow one to talk among the various 
running parts of an EMC.  In fact, you can see his example PLC in a file 
named emc/src/emcio/tkio.tcl.  This example is functionally parallel to 
bridgeportio which was written in c/c+.  You can run it by specifying tkio 
rather than bridgeportio, minimillio, or simio in your ini file.

Tkio uses a connector named emc/src/emcio/iosh.cc which is the connector 
between hardware, NML, and Tcl/Tk.  This file is documented a bit in the 
handbook along with emcsh which is the connector used by tkemc and tkemcex. 

Tcl/Tk is a rather intuitive language to get a sense of aux I/O at the level 
that it is applied in the EMC.  If you are serious about using a second 
parport or even a dio board for things like tool changers, robot parts 
changers and such, this is by far the easiest approach.

Some examples of I/O that run with Tcl/Tk are included under the scripts menu 
in such things as IO_Show, IO_Exercise, and probing.  

<s> So...am I still confused? I look at KT marketing's fine port pinout and I
> realize the nameing conventions are not the same as in IO_show.tcl (Kudos
> to the efforts of everyone who made these tools...I am a newbie, I need
> spoon-feeding)

I don't think so. <g>  I think that you can and will run your own spoon.  I 
had a hand in both of these and when you find errors point them out and we 
can fix both.

> BTW, I am planing to use Steppers. Does it make a difference in how the IO
> signals are interpreted?

Only to the extent that limits, homes, and step and direction pulses get 
fixed to specific pins on the parport that is assigned to the task of motion 
control. 

You should point at me for any errors in IO_Show.  In fact I seem to remember 
finding one in the labeling there some place but I can't remember where and 
at the moment of discovery, had other things in mind.  Must be that old 
timers stuff.

Hope this helps.

Ray