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Offline olf20

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Auto Tool Zero
« on: June 21, 2008, 07:22:14 AM »
Hi all hope everyone is doing well!!
I'm trying to get the Auto Tool Zero working  and have a problem with my breakout board.
I have C1 breakout board. I'm trying to use the Auto Z Zero setup described at the Mach3 Mill Forum. How do I get Pin 11 to be high in stead of low when at rest???
Here is a snippet of the thread --- Now here is the rub.  A lot of the BOB makers pull the inputs low with on board circuitry.
 
That is they are low when at rest.  This is fine for a limit or estop switch but ......
 
This device described in this thread needs an input that is high when at rest.

If I ground the probe the led on the bob will light, but I can not get the probe led to change state in the diagnostic screen. I can make it change state by switching the active hi / active low but not with the bob.

Any help would be appreciated!!

Thanks olf20

Mach3, Atlas Knee Mill, 4th Axis, VcarvePro, ESS, Super PID.
Been Heating with corn since 1998

Offline bowber

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Re: Auto Tool Zero
« Reply #1 on: June 21, 2008, 07:33:53 AM »
I think some other people have been caught out with this but I seem to remember that most got round it with a direct connection to their LPT port, apparentl some isolating bob's have a particular pin that is a straight pass through as well.

Which setup have you used, I saw a nice one on the CNC zone forum, good description and links to the code needed, Im going to set one up soon, my bob is a simple pass through though so no problem with reversed polarities, my drives have the isolation built in.

Steve

Offline Greolt

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Re: Auto Tool Zero
« Reply #2 on: June 21, 2008, 11:36:05 PM »

I have C1 breakout board. I'm trying to use the Auto Z Zero setup described at the Mach3 Mill Forum. How do I get Pin 11 to be high in stead of low when at rest???


Arturo at CNC4PC pulls all the inputs low on his BOBs.  Fine for limits and such, not so good for this auto tool zero input.

I use an older C10 BOB of his, before he started doing this. 

I actually pull my input high which successfully killed noise issues on the auto zero input for me.

If it were mine I would remove the appropriate resistor from the board.  But that's me.   ;D

I believe you can pull it high with a lesser R value resistor which will overcome the pulldown but you would need to ask someone with more electronic savvy than me about that.

Greg

Offline jimpinder

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Re: Auto Tool Zero
« Reply #3 on: June 22, 2008, 03:35:13 AM »
Yes - Board manufacturers do **** up the boards by introducing all these so called foolproof designs.

I take it that all that is required is to invert the signal from your probe. Just get a TTL NAND chip for a few pennies and put this on a little scrap of veroboard in your circuits box. They are usually quad sets, i.e. four in one chip. Wire two inputs together and take the appropriate output to your Bob. Wire your probe to the input. This will invert the signal from the probe to the Bob and provide a good strong signal to do it with. You will have three others for similar applications. You can buy simple inverters in a package as well - usually eight on a chip.

When the input from the probe is high (at rest), the two Nand inputs see this and switch the output to low (the Not function) - which is at rest on your Bob. When your probe goes low, there is no input to the Namd chip, so the output goes high.

I assume your Bob board will react to direct TTL signals.
Take the 5v and 0v needed to drive the chip from the Bob board.
« Last Edit: June 22, 2008, 03:39:42 AM by jimpinder »
Not me driving the engine - I'm better looking.

Offline olf20

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Re: Auto Tool Zero
« Reply #4 on: June 22, 2008, 08:12:51 AM »
Thanks for the replies!!
I will do a little testing on the board and see what will work the best.
I have emailed CNC4PC several times, but have not gotten back a reply.
I'm sure that they have had this issue asked before.

Just got a email from CNC4PC. They are putting together a document that will cover this.
They said it should be ready monday.
I willl post back with any info.
olf20
« Last Edit: June 22, 2008, 09:20:38 AM by olf20 »
Mach3, Atlas Knee Mill, 4th Axis, VcarvePro, ESS, Super PID.
Been Heating with corn since 1998

Offline Greolt

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Re: Auto Tool Zero
« Reply #5 on: June 22, 2008, 06:07:52 PM »

Just got a email from CNC4PC. They are putting together a document that will cover this.
They said it should be ready monday.
 


I will be very interested to see what Arturo comes up with.

Greg

Offline olf20

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Re: Auto Tool Zero
« Reply #6 on: June 27, 2008, 04:11:22 PM »
I just got this from CNC4PC
You need a pull up resistor connected between 5V and the  pin11.  I suggest a 220ohm (approx).  With this configuration it is required a solid low (GND) in order to get a low in that pin.

Hopes this helps! I will get back to my machine tomarrow and will report back.
olf20
Mach3, Atlas Knee Mill, 4th Axis, VcarvePro, ESS, Super PID.
Been Heating with corn since 1998

Offline olf20

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Re: Auto Tool Zero
« Reply #7 on: July 09, 2008, 07:11:31 PM »
Hi all, hope everyone is doing well!!
Well it tried the 220 ohm pull-up resistor today. After supplying the mill with a ground path I was able to get the led on the beakout board and the led in mach to trigger when I touched the bit with the plate. However I think I blew the opto chips on the breakout board (new ones on order) as the mill won't move.
I will discuss this with CNC4PC before trying again.
olf20
Mach3, Atlas Knee Mill, 4th Axis, VcarvePro, ESS, Super PID.
Been Heating with corn since 1998