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  #61  
Old Sun 17 February 2008, 22:17
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
12v coils.
I wasn't infering a differential voltage of 24 volts...only 12volts. I should correct the schematic to reflect otherwise.
The system, ideally, would be using the 12v I have native in the box and not introduce another voltage.

Thanks for looking at this.

SEan
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  #62  
Old Sun 17 February 2008, 23:08
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
My only other "schematic" comment is that you indicated one proxy each on each axis. My choice would be definitely 2 proxies on x-axis, 1 on y-axis and a "maybe" for the z-axis. The z-axis hassles are when it dives too deep and a fixed proxy can never detect that. (Some folk have sliding limit switches on the z).
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  #63  
Old Mon 18 February 2008, 06:31
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
Sean,
Those proximity switches must be Normally Closed for your circuit to work, otherwise you'll only get a 'contact' signal when all three sensors fault at the same time.
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  #64  
Old Mon 18 February 2008, 06:41
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Mike the metal targets will be present in front of the proxys in the "normal" condition. In the presence of that metal, the NO switches will close.

The targets are "abnormal" in this case - we are not trying to sense bolt heads or lumps of metal at the ends of travel. We look at the rail all the time, but there are holes at the end of the rails. When the proxy sees the hole, it changes state and opens the relay. Also when the car jumps off the rail.
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  #65  
Old Mon 18 February 2008, 07:26
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
Gerald,
Sorry. I should have remembered that the sensors are actually going 'active' when they sense the 'hole', which, as you pointed out, makes Sean's circuit work perfectly.
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  #66  
Old Mon 18 February 2008, 08:40
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
Gerald,
Thanks for verifying the "logic". I assumed we wanted to see the rail at all times incase of a "jump the track". Thus NO logic on the Prox.

Glad I ordered the correct thing....no canceling that order now
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  #67  
Old Mon 03 March 2008, 15:57
ekdenton
Just call me: Ed #8
 
Alamogordo, NM
United States of America
Are these proximity switches or sensors necessary? Is there an advantage to have them or are they just a nicety? I see three of them in some of the posts, why not six?

What is their purpose?

Can I do without these proximity or limit switches to start out with and add them later?
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  #68  
Old Mon 03 March 2008, 19:06
Doug_Ford
Just call me: Doug #3
 
Conway (Arkansas)
United States of America
Hey Ed,

Gerald wrote earlier that he still doesn't have switches on his machines. I don't have them on mine at the moment but I think I'd like to have them. I guess I'm just clumsier than Sean D. So I guess the answer to your question is that they're a nicety.

You actually only need four switches or sensors. One on both ends of the gantry, one on the car and one on the Z axis.

You can definitely start out without them and than add them later.
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  #69  
Old Mon 03 March 2008, 20:17
Greg J
Just call me: Greg #13
 
Hagerman, New Mexico
United States of America
Ed,

Agree with Doug. You certainly don't need them to get going or to have a productive machine.

I'm adding the prox. sensors, shuttle Pro, and Z-zero plate to make the mundane, every project essential starting point/process more efficient. I don't want to spend my time zeroing or finding my hard/soft limits for each new project.

You can add all or none of these items at any point. That is the beauty of building your own machine. Like any good receipt, you start with a good base (Gerald's design) and "add to taste".
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  #70  
Old Mon 03 March 2008, 21:07
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
Ed, (and others)
It took me less than 6 hours to mount,run all the cable, terminate and configure Mach 3 to work with the proximities. Gerald did all the hard work - he gave us a place to mount the sensors and a way for them to activate at the end of each axis. The only axis not accounted for was the z, which I made the mount, tapped the holes and painted in the above mentioned time frame. Cost was about 150.00 with all the cable and shipping. DEFINITELY a time saver when setting up the machine. Plus, the work offsets are nice to come back to after a "morning" home. I just click "ref all", click offset....and were cutting. ....almost shop labor proof...."almost"
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  #71  
Old Wed 05 March 2008, 05:41
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
Summary of the Proximity Switch usage

I have fielded a number of Emails and PM's recently to explain my installation of the proximity sensors on the MM per Gerald's design intent. A quick summary below based on my choices and design input from Mr. Richards, Doug, Gerald and others.

MechMate Proximity Limits


Schematic for installation: (this is correct, NO contacts wired in series to the PMDX input)
prox_layout.pdf

Details: FactoryMation
qty description
3 SI12-C2 NPN NO H m12QD proximity sensors, 10-30vdc
1 *cant find the part number* prox sensor like above with 30mm body length
4 PIR6W-1P-12VDC slim relay
3 MOD.14/4 LC5 5m qd cable. (right angle connector) - x and z axis. I extended each cable with 4 core cable to meet my needs.
1 MOD.14/4 LC5 5m qd cable. (straight connector - ycar only)

Please note that the prox switch is NO logic
The relays are wired NO logic.
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  #72  
Old Wed 05 March 2008, 07:44
sailfl
Just call me: Nils #12
 
Winter Park, FL
United States of America
Sean,

You forgot that you actually need 4 sensors. 2 for x and 1 for each y and z.

The diagram need one additional sensor added. I only know this because Sean and I talked about it.
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  #73  
Old Wed 05 March 2008, 09:58
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
Nils,
Correct, I didn't update the schematic like the parts list I just posted.
All still applies. Just add 1 more sensor in series for the x axis for a total of 4. Good catch.
Thanks,
Sean
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  #74  
Old Wed 05 March 2008, 10:22
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
In my mind's eye we still have a "box" riding on the gantry, with a logic board inside, as discussed in this thread a month ago. The blue thing in the sketch below. Realise that there are 35 wires and 4 screens to be taken care of inside there . . . .

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  #75  
Old Wed 05 March 2008, 11:45
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
Gerald,

What you've posted is a classic multiplexer/demultiplexer, which is just another name for 'switch box'. The next thing that we'll need is a chart that lists each device and its destination, such as:
Push Button Station 1, Red PB (N/O) -> Pin 11
Push Button Station 2, Red PB (N/C) -> Pin 11

From that, a circuit can be drawn and a circuit board can be built.

Last edited by Richards; Wed 05 March 2008 at 11:48..
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  #76  
Old Wed 05 March 2008, 13:42
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
I just get drawn into the forum whenever Mike post's something.
It's like watching Einstein discuss the theory of relativity.
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  #77  
Old Wed 05 March 2008, 14:08
Greg J
Just call me: Greg #13
 
Hagerman, New Mexico
United States of America
Quote:
Originally Posted by Gerald D View Post
Mike the metal targets will be present in front of the proxys in the "normal" condition. In the presence of that metal, the NO switches will close.

The targets are "abnormal" in this case - we are not trying to sense bolt heads or lumps of metal at the ends of travel. We look at the rail all the time, but there are holes at the end of the rails. When the proxy sees the hole, it changes state and opens the relay. Also when the car jumps off the rail.
Ed,

Gerald's post answers the NO question.
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  #78  
Old Wed 05 March 2008, 18:43
Doug_Ford
Just call me: Doug #3
 
Conway (Arkansas)
United States of America
Quote:
Originally Posted by Richards View Post
The next thing that we'll need is a chart that lists each device and its destination, such as:
Push Button Station 1, Red PB (N/O) -> Pin 11
I'll try my hand at this but I may need help with the Z zero plate and the black button on Gerald's 4 button station.
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  #79  
Old Wed 05 March 2008, 18:48
Greg J
Just call me: Greg #13
 
Hagerman, New Mexico
United States of America
Sean, or anyone

Ed asked myself a question that I can't answer. I thought I understood the wiring and logic, but I don't.

On the relays, what pin numbers are you using for the latching side? In your earlier photo, it looks like pins 12 and 14. That makes no sense because its an open circuit

Pins 11 and 12 makes sense, but that would be NC and you said it's NO. Also, on three NO relays in series, how can the BOB recognize anything when only one out of three switch's closes.

A1 and A2 are jumper-ed and that makes sense.
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  #80  
Old Wed 05 March 2008, 19:02
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
Greg,
Pins 11 and 14 of the relay are wired in series to the input #15 on my PMDX.
It's open when not energized, closed when energized. Whenever the machine is powered "on", it's energized and closed.
When homing or seeking limits, the proximity switch "sees" the hole in the rail, opens the relay, opens the switch and activates the pmdx. Then, because the Mach routine for homing is smart. Mach will seek the switch, activate, them reverse the axis until it is cleared then move to the next axis. Mach's sequence is designed around using multiple switches (regardless of type) to utilize only 1 input on the BOB, thus freeing up inputs for other things. Like a pause and resume button on the gantry, or z-zero function button.

Page 8 of the pmdx manual show's "loosely" multiple switches configured to a single input for this reason.

Ed and I have exchange multiple emails over the past number of days discussing the NO / NC reasoning.

I like the switches powered in parallel, but input wired to the BOB in series via a NO contact. I have many reasons for this, but mostly a NO contact would show a failure to the BOB if one of the sensors is not powered on or a wire is broken because the switch MUST activate and pull in the relay to work. A NC switch in this case may not show a fault until you try to home or hit the limit, then you would find the machine crash into the hard stop....or you get to listen to the z-axis grind teeth for lunch.

Let me know if I have explained this logic well enough...I feel like the NO / NC switch choice battle isn't over on the forum yet.

For me, my MM works like a champ set up like this and I have even de-railed the machine on purpose to test me theory....its works well.

*Gerald and Mike can chime in here and help me any time now *
Sean
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  #81  
Old Wed 05 March 2008, 19:20
Greg J
Just call me: Greg #13
 
Hagerman, New Mexico
United States of America
Sean,
Everything was making perfect sense until this part.

Quote:
Originally Posted by smreish View Post
I like the switches powered in parallel, but input wired to the BOB in series via a NO contact. I have many reasons for this, but mostly a NO contact would show a failure to the BOB if one of the sensors is not powered on or a wire is broken because the switch MUST activate and pull in the relay to work. A NC switch in this case may not show a fault until you try to home or hit the limit, then you would find the machine crash into the hard stop....or you get to listen to the z-axis grind teeth for lunch.
What NO contact ? Am I missing something in your schmatic?
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  #82  
Old Wed 05 March 2008, 19:44
sailfl
Just call me: Nils #12
 
Winter Park, FL
United States of America
Sean

I wish you guys would have these talks on the threads because I am sure that others like me would like to be able to understand this stuff. I want to understand how these things work. I am learning many things and I hope once I get my machine built and running that I will be able to share some of my software experience.
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  #83  
Old Wed 05 March 2008, 19:45
Doug_Ford
Just call me: Doug #3
 
Conway (Arkansas)
United States of America
Greg J,

I was waiting on Sean to answer this one but it looks like he's signed off so let me see if I can answer it.

The prox has a normally open switch inside it. When the circuit is energized, it closes as long as the metal rail is in front of the sensor. That's the way I understand it anyway.
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  #84  
Old Wed 05 March 2008, 20:38
Doug_Ford
Just call me: Doug #3
 
Conway (Arkansas)
United States of America
Quote:
Originally Posted by Richards View Post
The next thing that we'll need is a chart that lists each device and its destination, such as:
Push Button Station 1, Red PB (N/O) -> Pin 11
Will someone please check my work before Mr. Richards starts designing a circuit.

Push button station 1 (On Car)
Red PB (NC) -> J6 Estop
Red PB (NC) -> Contactor
Green PB (NO) -> Pin 15
Yellow PB (NO) -> Pin 13
Black PB (Gerald, I can't remember what you had in mind here. I think it was for the Z zero.)

Push button station 2 (On Gantry Front)
Red PB (NC) -> J6 Estop
Red PB (NC) -> Contactor
Green PB (NO) -> Pin 15
Yellow PB (NO) -> Pin 13

Push button station 3 (On Gantry Back)
Red PB (NC) -> J6 Estop
Red PB (NC) -> Contactor
Green PB (NO) -> Pin 15
Yellow PB (NO) -> Pin 13

Z Prox (NO) -> Pin 12
Car Prox (NO) -> Pin 12
X Front Prox (NO) -> Pin 12
X Back Prox (NO) -> Pin 12

Z Zero Plate (NO) -> Pin 11
Probe (NC) -> Pin 11
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  #85  
Old Wed 05 March 2008, 20:52
Greg J
Just call me: Greg #13
 
Hagerman, New Mexico
United States of America
Thanks Doug,

I think that does help.

The Prox. is NO, but since it see's the rail, it activates (sorry if terminology is incorrect). Since it's "activated" (closed) the solenoid in the relay is energized, closing the latch in the relay.

Now, under normal conditions, all three relays are closed, because the Prox. sensors are seeing the rail and are closed. When the Prox. see's the hole at the end of the rail, it opens, de-energizing the solenoid in the relay, opening the latch. The BOB see the new condition and knows it's at zero (if ref all) or in a fault (if gantry de-rails, or whatever).

Aaaah, light bulb is starting to glow.

Does that help Nils?
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  #86  
Old Wed 05 March 2008, 21:41
revved_up
Just call me: Craig
 
Hartland, MI
United States of America
Sean, where does the +-12vdc come from?
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  #87  
Old Wed 05 March 2008, 22:21
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
There was a good question in here last night, which the poster shyly decided to delete again:

"I am trying to wrap my head around the layout and wiring of either proximity sensors or the switches. I take it that the main purpose of these is to allow mach to be programed to set the router in a home position in all three axis's.

Okay if that is the goal, I do not understand wiring three or four sensors in series NO would work. Reason being, how does mach know which sensor tripped when they are all in series? "


Your car is parked in your garage and the garage door is closed. You get in the car, start the engine and you are now going to drive. Your name is Mach3, you are blindfolded. You (Mach3) puts the car in reverse and drives. Mach3 hears a bang, (the garage door is hit). Mach3 puts the car in Drive, goes forward and hears another bang (the front wall is hit). Mach3 being a normally bright person has figured out that the bang after reverse is the door and the bang after Drive is the front wall. Mach3 only needs one bang sensor.

On the router table, you can wire everything in series, to make one big sensor, because Mach3 is smart enough to know what it was doing before it hits this sensor, and therefore figures out which part of the sensor it hit.

And then, to give some perspective, this bit:
"I take it that the main purpose of these is to allow Mach to be programed to set the router in a home position in all three axis's."

The reason we manage to mostly get by without any switches is because we "home" the machine to the corner of the material lying on the table. After changing a cutter, manually jog the cutter over the corner of the material and set x and y to zero from the keyboard. Then jog the cutter till it just touches the surface and set z to zero. Then start the cut.

A home switch on the z-axis can never tell you the distance between the cutter and the material. Home switches on the x & y can only tell you the distance to the material if the material is located to the same spot everytime.

But there are times (not many) when we wish we did have proximity switches . . .
- When there has been a glitch (power failure?) in the middle of a sheet of material and we need to find the reference points again.
- When the cutter hits a clamp and the car jumps off the rail.
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  #88  
Old Thu 06 March 2008, 02:58
sailfl
Just call me: Nils #12
 
Winter Park, FL
United States of America

To go along with the list Doug made for the Circuit, please add an output.

Laser Control (NC) -> Pin 14

Thank you
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  #89  
Old Thu 06 March 2008, 03:23
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Nils, we are not getting into lasers. . . . yet.

(Besides, from the little I have read, lasers often need an analog ramp up/down for engraving, to avoid burning through when motors are accelerating/decelarating.)
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  #90  
Old Thu 06 March 2008, 05:08
sailfl
Just call me: Nils #12
 
Winter Park, FL
United States of America
Gerald,

You misunderstood..... I am not getting into lasers for cutting. This the crosshair laser.

Discussed here: http://www.mechmate.com/forums/showthread.php?t=596

Hope that clears that up. I have my hands full just trying to understand the router build. I could have made it clearer and said crosshair laser.

We need an output for the crosshair laser. NC -> Pin 14

Last edited by sailfl; Thu 06 March 2008 at 05:10..
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