[Lathe] Fanuc OT to DC_CNC conversion

Charcole said:
wow, I've never seen a pre 95 cnc with a tool eye. Pre 90's CNC's I have ran but I guess employers get cheap. Sounds familiar today even. Looking at that pick with the turning tool reminds me tool room lathe with just tool post. Is it 90 or 60 slant.
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I think it's a 60.

I discovered another small problem, the home position was not consistent or rather there were two ''home'' positions. It turned out to be a function of what side of the home switch cam you started on. I fixed that by not using the home switch at all. Now I'm using the travel limit as the home switch so there is only one possible direction to approach the switch. Gently hit the travel limit, back off, rotate the motor in the negative direction to the encoder index pulse. The home position is now consistent to 0.0001''

Still haven't made any real chips, but soon. :)
 
JimDawson said:
I think it's a 60.

I discovered another small problem, the home position was not consistent or rather there were two ''home'' positions. It turned out to be a function of what side of the home switch cam you started on. I fixed that by not using the home switch at all. Now I'm using the travel limit as the home switch so there is only one possible direction to approach the switch. Gently hit the travel limit, back off, rotate the motor in the negative direction to the encoder index pulse. The home position is now consistent to 0.0001''

Still haven't made any real chips, but soon. :)
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That's always been my understanding that the travel switch was the home switch. But now that you mention that I do recal seeing two rollers on a couple of machines.
 
In this case, there are 2 switches and 3 cams on each axis. One switch is the travel limit the other is the home switch. The travel limit is operated by a cam at each end of the travel, the home switch has a seperate cam. Some machines have 3 switches according to a schematic that I have.

Now that I am not using the home switch, I'm going to do a little rewiring and use a seperate switch for each end of the travel. This will eliminate the need to perform a limit switch override to move the axis off of the travel limit in case of an overtravel. This will be especially useful when using the MPG
 
You must be a more clever programmer... I had tried to get away without installing a home switch on one axis - knee. Had reliability issues, ended up installing the extra switch. would you care to share the galil code for homing off a limit?

Karl
 
Happy to share Karl. The key to accuracy is not to use the switch itself for actual positioning, but rather use the encoder index pulse (FI command). But this does only work if the encoder has an index output. It is possible to use only the switch if it is repeatable. You could wire the switch to the index pulse input as well as connecting it to the limit input, in that case you would want to move the LDA=0 after the FI routine and maybe have to move the axis off of the limit before setting LDA=0. The index input is limited to 12V max, but I normally supply the limits with 5V.

#HOMEA
LDA=3;'DISABLE TRAVEL LIMIT
FLA=2000000;'SET FORWARD SOFTWARE LIMIT TO A HIGH VALUE
DCA=1000000;'SET DECEL HIGH SO THE AXIS STOPS ALMOST INSTANTLY
JGA=20000;'SLOW JOG FORWARD, TOWARDS THE LIMIT SW, ABOUT 20MM/SECOND
BGA;'BEGEN MOTION
#G
JP#G,(_LFA=1);'LOOP UNTIL LIMIT IS HIT (_LFA=0)
STA;'STOP AXIS
AMA;'AFTER MOTION COMPLETE
IPA=-10000;'BACK OFF OF LIMIT 10000 COUNTS, ABOUT 10MM
AMA;'AFTER MOTION COMPLETE
LDA=0;'ENABLE TRAVEL LIMIT
HVA=1000;'SET HOMING SPEED TO 1000, DEAD SLOW
FIA;'FIND ENCODER INDEX PULSE
BGA;'BEGEN MOTION
AMA;' AFTER MOTION COMPLETE
WT10;'WAIT 10 MS
FLA=1000;' SET FORWARD SOFTWARE LIMIT TO 1000 PULSES
RLA=-174000;' SET REVERSE SOFTWARE LIMIT TO ABOUT 6MM OFF OF REVERSE TRAVEL LIMIT
EN
 
Thanks, you have a couple program ideas I've not used. I am getting rusty as it has been five years since doing a galil refit. trouble is the machine is so dang reliable, I just don't ever touch it.
 
brino said:
I need more of those kind of troubles!
-brino
Click to expand...

I should clarify, its the software that never breaks. Those very few of us that use galil know its world class quality.

Karl
 
Jim, spent some more time with your program...

My Galil Command reference has NOTHING about LD. I assume its stands for LIMIT DISABLE. That's the key I was missing, my program would jump to #limswitch <default limit switch routine> and not always jump back

Does not have HV command either for that matter. I do remember a work around here as my home routine creeps to the index mark.

So I've not been using a full deck. Do I just need to look for a newer command reference? I use all DMC18x0 cards if that matters.

Capture.JPG
 
Karl_T said:
I should clarify, its the software that never breaks. Those very few of us that use galil know its world class quality.

Karl
Click to expand...

Karl, Jim has helped me a great deal in getting my mill running with Galil. Since it was my first CNC conversion, I probably am sort of oblivious to other manufactures cards and their behaviors. I know there are the run of the mill (pun intended) setups that use Chinese cards and can be had for a fraction of the price. What makes Galil superior to those?
 
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