TkEmc problems

[Jon Elson <jmelson-at-artsci.wustl.edu>]

To: Fred Proctor and others working on the TkEmc interface

I had some problems with TkEmc over the weekend.  It was the
first time I did some serious work with it, and I ran into some
very strange behavior, including something that is pretty dangerous.

I had motion on axes that I was not commanding to move, in
MDI.  Here is what I did :
1.  X17.25 F10
2. X0
(so far, everything was fine)
3. Y-.02
(observed a positive X move.  I think it was moving
to X17.25 Y-.02, but I had to abort it before it caused a problem.)
I saw it do this 3 times, in about an hour of work, where I did
this operation about a dozen times.  It always was on the MDI
move of the Y axis alone, on a very short -Y move, after a very
long X move + and then back to about X0.

I also found several other problems or odd behaviors, none of which
is so serious as the above.

This one is present (at least in older) Xemc as well as the current TkEMC
20-Dec-1999.  When switching modes (man, auto, MDI) and then
back to manual, the jog velocity shown on the screen is not used, but
jogging occurs at the last feed rate set by the last program run.  Pressing
a feed rate override key sets the jog speed correctly.

In TkEmc, f you externally edit an RS-274D file, and then attempt to
reload the file with the open command, and OK the dialog box, the
new program DOES not show on the screen.  You see the old program.
When you execute it, You see it work down the OLD program lines,
while it correctly executes the NEW program lines.  The only way to
refresh the view is to load some different program by name, then reload
the new program by name.  If you use the edit window, you see the
new program, but if you don't change it, it still doesn't update the
program text on the main display.

When running with work offsets (G10 L2 P2 and G55) it works fine
the first time, but resets as if you had entered a G54 at the end of the
program.  To return to the correct work offsets, you need to do a
G55 again.  (Modes in force display shows G55 all the time.)
This is in TkEmc, also.  Last time I did this in Xemc, it was OK, but
I haven't used this feature in the 20-Dec-1999 Xemc version.

TkEmc highlights the bottom line in the program display window, but
that is not always the line being executed.  It often shows a line about
2 past the one it is currently executing.  Sometimes, it DOES show
the current line highlighted, on the bottom line, so you have no idea
what is coming next.  I suppose this could be just TkEmc running
behind in updating the display, but it could be several seconds behind
the motion control system.

Thanks,

Jon