Find current location?

Can someone point me to some reference material that would help me understand what I would need to do to write a bit of code for the ShopBot DeskTop? I want to write a routine similar to C3 that moves to the X,Y proximity switches but doesn't zero the X,Y axes. That way I can find out the absolute coordinates of my current position and use it to set up my home position quickly.
I've had to re-calibrate about 6 times today because of one mistake or another the spindle has run up against one of the stops or slipped because I forgot to set the spindle speed correctly, and thereby lost its alignment for that axis.

It sounds like you may not have your C3 homing routine set up properly. If you have never set it up using TS (Tools ShopBot Setup) or by manually entering the proper values for the offset distance between the prox sensors and the true 0,0 of your table in the 'C:\SbParts\Custom\my_variables.sbc' file, it will use the defaults of 0.5" for both the X and Y axis. Once set properly, if you lose position, you can C3 to reset to absolute 0,0. If you happen to zero X and Y at another location, you can just do ST to reset to table base coordinates. If you're using version 3.8.XX, you can use the memorize buttons on the Keypad to memorize and return to locations previously set.

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Originally Posted by srwtlc

It sounds like you may not have your C3 homing routine set up properly. If you have never set it up using TS (Tools ShopBot Setup) or by manually entering the proper values for the offset distance between the prox sensors and the true 0,0 of your table in the 'C:\SbParts\Custom\my_variables.sbc' file, it will use the defaults of 0.5" for both the X and Y axis. Once set properly, if you lose position, you can C3 to reset to absolute 0,0. If you happen to zero X and Y at another location, you can just do ST to reset to table base coordinates. If you're using version 3.8.XX, you can use the memorize buttons on the Keypad to memorize and return to locations previously set.

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scott, this is an interesting thing for the prox sensors.
I have a 96X48 prs alpha with 4hp spindle and 12"Z. I carved a grid system and numbers into my spoilboard with 0,0 being lower left on the bed. the MDF I have was about 2" bigger than 96X48" so I have the overhang on the left and bottom sides and that is where I put the numbers.

Sometimes I lose my zero due to whatever, and the table base coordinates are also off. meaning wherever the machine thinks zero is, is not lining up with my grid system. So I throw the v bit in and slow the move speeds down to .05 and sink the v bit into the actual 0,0 and then reset everything.

I tried to move my prox switches to line up with the grid system 0,0 but can never get it close enough...

are you telling me that I dont have to get them close at all, and that wherever they actually are relative to my self made 0,0 I can just assign an offset and use the prox switches to actually zero my machine?!

I know that was a long explanation/ question, if it is confusing, let me know and I can upload pictures. thank you for any help/ insight.

Justin,

In a word, yes.

Long answer....I generally position the prox switches a 1/2" before the mechanical stops. Then you would position the tool at the true table 0,0 (you can do this with a v-bit as you have done before and get it as close as possible or it can be done with a touch off plate xy zeroing fixture that I won't get into at this time here). Once you have it at that location, do a Z2 to set the XY DRO's to 0.00 and then run ShopBot setup under the tools menu. As you go through that step by step, check the appropriate items that you want to set up (prox switches being one of them) and when you get to the page for setting the prox switches, select 'Make it easy on me' and click the big 'Make it easy on me' button and follow the prompts.

When the set up is done, your offsets from table 0,0 to the prox switches are saved and you can now use C3 to home the machine to the table 0,0 at any time.

If you reposition the prox switches, or I should say the targets, as you can't move the proxes, set the gap with a piece of tag board or something around 1/32" thick. Don't forget to adjust the targets at the other end of each axis also.

If you have further questions, come back for more. ;)

Scott,
thank you for this response. I am going to knock this out first thing in the morning.
I am assuming using the prox switches to set a zero will not interfere with my table base coordinates correct?

similar to if I ran the machine to 10,10 and set that as a zero with a z2, then did whatever, then typed in ST at that "new" zero location, the location would update to 10,10 again instead of 0,0? If that is correct, then the same should be applied to the prox switch zeroing yes?

Justin, using the prox switches to home the machine with C3 (if the prox switch offsets are properly set), sets the table base coordinates at that time. If you move to another location and issue a Z2, that location is your working coordinates and the table base remains as set with the proxes and C3. As you stated, a ST will set the DRO's back to table base coordinates. If you issued a ZT, you would change the table coordinates to that new location (seldom if ever used).

One thing i do in case of situations like this where you don't want to lose work if you lose all settings is, prior to starting work i do a C3 to find table Zero.

Then i manually jog over to my material X,Y zero (I usually set mine in the center of material). I then write down those X,Y coordinates. Then I Zero X,Y.

So now if the gremlins sneak in on me during or between cuts all i have to do is go back do a C3, MX24, MY24 (or whatever the written down coordinates numbers are) and i'm back to manual center of the material even though all settings were lost like in your situation.

Jack and Scott,
Great points and I'm learning. Thank you. I'm at my computer/bot right now and just made sure with a 60deg V bit that my table base zeroes were on point. Now going to make sure the prox targets are near the mechanical stop blocks...

Here's the automated way of Jack's paper and pencil method. ;)

Quote:

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Originally Posted by srwtlc

Justin,

In a word, yes.

Long answer....I generally position the prox switches a 1/2" before the mechanical stops. Then you would position the tool at the true table 0,0 (you can do this with a v-bit as you have done before and get it as close as possible or it can be done with a touch off plate xy zeroing fixture that I won't get into at this time here). Once you have it at that location, do a Z2 to set the XY DRO's to 0.00 and then run ShopBot setup under the tools menu. As you go through that step by step, check the appropriate items that you want to set up (prox switches being one of them) and when you get to the page for setting the prox switches, select 'Make it easy on me' and click the big 'Make it easy on me' button and follow the prompts.

When the set up is done, your offsets from table 0,0 to the prox switches are saved and you can now use C3 to home the machine to the table 0,0 at any time.

If you reposition the prox switches, or I should say the targets, as you can't move the proxes, set the gap with a piece of tag board or something around 1/32" thick. Don't forget to adjust the targets at the other end of each axis also.

If you have further questions, come back for more. ;)

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Got it all set up, works like a charm. Wish I would have figured this out about 1,000 lost zeros ago. Thank you for your help on this!

I have not lost position too many times, but I sometimes run a short file to mark the position -1, -1 about 1/8 inch deep.

Should you somehow need to set back up up / You can manually move the bot over to the -1, -1 mark, zero xy... and then move to 1, 1 and zero xy again.

This should put you back where you were within .001 or .002 which works well enough most times.