Re: 4th axis working

[Dan Falck <dfalck-at-sprynet.com>]

Lawrence,

I worked on this setup today and was able to learn a few things.  To get 
the GUI working, you have to alter all the references in tkemc that is in 
the /usr/local/nist/emc/plat/linux_2_2_14/bin directory to the axis 
info.  I added another axis by doing a search for anything having to do 
with the word "axis" and duplicating it.  Then, I added a 4th axis in the 
emc.ini file by duplicating the axis.  As soon as I can, I will upload my 
version of "4axtkemc" , "4axemc.ini", and "4axemc.run" to the dropbox in 
linuxcnc.org.
One thing that I learned today was that the 4th axis had to be set up as 
"LINEAR" instead of "ANGULAR", to make the rotary table run in sync with 
the other axis'.  When I had it set up as "ANGULAR" it would run short if 
the linear axis made it to their destination faster than the rotary 
table.  An example of this would be the commands G0 x0 a0,  G0 x1 a10 - the 
rotary table only made it to a=5.  So, I changed it to linear and it seems 
to work.
As far as a screen shot, it's not all that interesting- just an entry for 
the A axis right under the Z axis readout on the tkemc screen.

Another thing that I learned about 4axis EMC (it was in Will's release 
notes) is that it can be tricky mixing linear and angular movement when it 
comes to rapids.  If the rotary table has to move a lot and the linear axis 
doesn't, you can get a follow error.  It's going to take a while for me to 
get things working the way that I want, but I have had a lot of fun playing 
with this and learned a lot more about Tkemc.


I ran into a bug having to do with tkemc.  When I first open tkemc, it 
comes up defaulting to G21 metric mode.  If I go into MDI right away and 
give it a G20 command and then try to issue another command, it locks up my 
computer hard.  If I start tkemc and go right into manual mode and try to 
move the machine right away it locks up too.  So, I now open it, get it out 
of estop, turn on the machine, THEN press the MDI and Manual buttons 
alternatively a few times and things will work fine.
Another bug in the new version is the inability to restart a program in 
Automatic mode, without having to open the same program again. So, if you 
are running a lot of parts and have to do multiple cycles, you will have to 
open the part program every time you want to start the cycle again.

Dan



At 12:35 AM 2/16/01 -0500, you wrote:

>Good news Dan,
>any chance you have some notes on the process that you would share with the
>group? Did you use the Bridgeport controller module or start from scratch?
>What GUI did you end up with? A screen shot would be interesting.
>Getting more axis online is one of the items in my to-do list once I get
>some driver hardware built.
>cheers
>=======================================================
>Lawrence Glaister VE7IT             email: lg-at-jfm.bc.ca
>1462 Madrona Drive                    http://jfm.bc.ca/
>Nanoose Bay BC Canada      http://gspy.sourceforge.net/
>V9P 9C9               http://members.home.net/cncstuff/
>=======================================================
>----- Original Message -----
>From: Dan Falck <dfalck-at-sprynet.com>
>To: Multiple recipients of list <emc-at-nist.gov>
>Sent: Thursday, February 15, 2001 8:12 PM
>Subject: 4th axis working
>
>
> >
> > I have a rotary table running with EMC now.  Tomorrow, I will tweak things
> > up and make some parts with it.
> >
> > Thanks guys!
> >
> > Dan
> >
> >