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  #61  
Old Sat 26 September 2009, 23:45
MAC2009
Just call me: MAC
 
West ST Paul, MN
United States of America
witch bob

I would like to know my most of you the PMD over the CandCNC?

Mac
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  #62  
Old Sun 27 September 2009, 04:00
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Because we have good experience with it, no complaints, good docs, good support, good price.
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  #63  
Old Sun 27 September 2009, 23:14
BartDeckers
Just call me: Bart_D
 
Antwerpen
Belgium
Mike,

Thanks for the info
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  #64  
Old Sun 01 November 2009, 19:11
cncb
Just call me: Brian
 
Connecticut
United States of America
Gerald you had mentioned the PMDX-125 awhile back and I was just checking it out. Does anyone know of any mechmate builders/members with it running? Looks very promising! Still as you said, would be good to wait and see, let them debug everything. Don't like being a guinea pig while cutting!
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  #65  
Old Tue 13 July 2010, 07:32
Red_boards
Just call me: Red #91
 
Melbourne
Australia
Under the assumption that the board had been around for a while now, I got the PMDX-125 Gecko 203v bundle from PMD and am now assembling a kitchen table experiment (waiting for motors to arrive). Hoping some one has by now tread this path and is willing to share some tips.

I'm not too stressed about frying the Geckos (internally fused), and think I can hook up the BOB (even though it is 240v at one end - more than I like in live circuits), but I'd love some pointers on wiring the estop and Gecko fault detection and, especially, some of the silly things to avoid with this particular setup.

PS one of the nice things is that the parallel port ground and output ground are ( optically? wtm) separated
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  #66  
Old Tue 13 July 2010, 09:07
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Quote:
Originally Posted by Red_boards View Post
. . . I'm not too stressed about frying the Geckos (internally fused) . . . .
A reversed supply polarity still fries them, fuse or not, I am told.....
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  #67  
Old Wed 14 July 2010, 01:06
Belli
Just call me: Greg
 
Johannesburg
South Africa
The 203's are pretty indestructible, reverse polarity will fry the internal fuse (a 15A part), replacement is bit of pain if you have mounted them in the enclosure already. Spare fuses are available from Gecko or Digikey, I don't have the part number handy.
Greg
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  #68  
Old Wed 14 July 2010, 02:30
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
See this post on the Gecko yahoo forum, where a G203 owner sent it in for repair and got warned that reversed polarity can damage the drive.
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  #69  
Old Fri 23 July 2010, 01:03
tangocharlie123
Just call me: Pete
 
Gatton Brisbane
Australia
Quote:
Originally Posted by cncb View Post
Gerald you had mentioned the PMDX-125 awhile back and I was just checking it out. Does anyone know of any mechmate builders/members with it running? Looks very promising! Still as you said, would be good to wait and see, let them debug everything. Don't like being a guinea pig while cutting!
Following on from CNCB's post

Has anyone tried these yet as I am about to place an order for BOB and drivers.

All help and recomendations greatly appreciated.

Cheers
Peter
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  #70  
Old Fri 23 July 2010, 06:48
PEU
Just call me: Pablo
 
Buenos Aires
Argentina
I purchased one and I'm on my way of building the control box, I already built a control box with the 122 (not mechmate related)
Most of the help you will find here in the forum is for the 122, if you feel confident about interpreting the manual I would go 125, otherwise 122.
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  #71  
Old Fri 23 July 2010, 07:59
KenC
Just call me: Ken
 
Klang
Malaysia
Pete, almost all BOB of different make using parallel port can be use. You just need to do enough research...
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  #72  
Old Sat 24 July 2010, 08:27
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
The main function of a Break-Out-Board is to amplify (and protect) the parallel port signals. I use the PMDX-122. It is an excellent board, but there is no reason that you couldn't build your own, if buget is a main consideration and time is not a factor. A single chip can handle all the step and direction signals for a 4-motor machine. Another chip can handle all the input signals and a third chip can handle the output signals.

The Geckodrive G201, the G201X, the G202 and G203v stepper drivers (most commonly used) all have built in opto-isolation. You would need to add opto-isolation to the input signals and the other output signals, but each 4N2x chip costs about $0.25 each. Add a wall-wart type 9VDC transformer and an on-board 7805 voltage regulator and you would have your own break-out-board.

Building wire-wrapped boards is no longer "fun" for me. I either design boards and then have the boards made (at several hundred dollars for the inital prototype) or I buy ready-build boards (like the PMDX-122 for about $90). But, if you're in for a little design work and a little excitement, build your own. For some, it is part of the experience of building a machine.
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  #73  
Old Sat 24 July 2010, 22:23
KenC
Just call me: Ken
 
Klang
Malaysia
If you can design PCB, you can also cut out PCB with MM... or wash your own PCB with conventional method.
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  #74  
Old Sun 25 July 2010, 04:11
Red_boards
Just call me: Red #91
 
Melbourne
Australia
Quote:
The Geckodrive G201, the G201X, the G202 and G203v stepper drivers (most commonly used) all have built in opto-isolation
Hi Mike,
I had to look up opto-isloation and I found it is a way of transmitting a signal while keeping circuits electrically separated.

I remember there were discussions about the computer ground needing to be separate, so I guess this is the reason the PMDX125 the parallel port ground and output ground are alledgedly optically separated. I'm guessing then that I need to keep the parallel cable isolated from the case if I earth the BOB to the case?
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  #75  
Old Sun 25 July 2010, 04:52
KenC
Just call me: Ken
 
Klang
Malaysia
The opto-insolator is use to as the name implies, isolate the source & load, in this case the signal from the PC to the driver in the event of overloading or short circuits... etc. not really about the grounding...
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  #76  
Old Sun 25 July 2010, 07:48
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
Red,
Ken is right about opto-isolators. Their purpose is to keep the electrical noise that is generated outside the control box from entering the control box and messing with your computer.

It is good practice to ground ALL D.C. signals to a common ground lug, including those that are opto-isolated.

An opto-isolator is an inexpensive device that is commonly used to translate different voltages. For example, I use 12VDC proximity sensors. One side of the opto-isolator is connected to the 12V equipment. The other side of the opto-isolator is connected to the 5V controller side. Only light passes between the 12V and the 5V devices. (That's the 'opto' in opto-isolator.)

Opto-isolators are also commonly used to isolate any signal outside a process control computer's box from the process control computer's circuits, even when the voltages are the same. The cables that connect the control box to the machine sometimes act like antennas and collect all kinds of noisy garbage. Putting an opto-isolator between the inside world and the outside world keeps the 'garbage' out. (Sorry for the metaphor, I know that Gerald's livelyhood depends on 'garbage', but electrical 'garbage' is really nasty stuff.)

Because opto-isolators are usually slow to change state (1 to 10 milliseconds), fast acting electrical noise is too short in duration to activate the signal. Also, because the input L.E.D. inside an opto-isolator requires current to 'turn on', most noise lacks the 5mA to 10mA required to light up the L.E.D.

On my Shopbot, when I installed opto-isolators on the input lines, ALL of the communication errors disappeared. The parts cost less than $10. The result was priceless.
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  #77  
Old Sun 25 July 2010, 20:33
Red_boards
Just call me: Red #91
 
Melbourne
Australia
My students are back at uni this week with a ton of learning ahead of them ... I know how they feel!
Thanks for the clear explanation. I have a much better handle on where to apply opto-isolators now.
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  #78  
Old Mon 02 August 2010, 02:56
renraku
Just call me: renraku
 
rome
Italy
correct color wire

Hi i need of your suggestion, i have this stepper motore nema 34 there are 8 wire, what are the correct 4 wire color for gecko g203v and where i have to connect to geckos ? For example yellow to phase A ect. thanks
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  #79  
Old Mon 02 August 2010, 04:33
renraku
Just call me: renraku
 
rome
Italy
Quote:
Originally Posted by renraku View Post
Hi i need of your suggestion, i have this stepper motore nema 34 there are 8 wire, what are the correct 4 wire color for gecko g203v and where i have to connect to geckos ? For example yellow to phase A ect. thanks
i forgot to upload pictures sorry
Attached Images
File Type: jpg motore2.jpg (122.0 KB, 865 views)
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  #80  
Old Mon 02 August 2010, 07:59
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
The M1343020 motor has eight leads, which means that it has four coils. Coil A1 has the Red and the Yellow leads. Coil A2 has the Blue and the Black leads. Coil B1 has the White and the Orange leads. Coil B2 has the Brown and the Green leads.

To wire the motor half-coil, connect the Red wire to terminal 3 on the G203v (Coil A). Connect the Yellow wire to terminal 4 (Coil /A). Connect the White wire to terminal 5 (Coil B). Connect the Orange wire to terminal 6 (Coil /B).

To wire the motor bipolar parallel, connect the Red wire and the Blue wire to terminal 3. Connect the Yellow wire and the Black wire to terminal 4. Connect the White wire and the Brown wire to terminal 5. Connect the Orange wire and the Green wire to terminal 6.

The motor has 1.5mH inductance per coil, so I would use a 35VDC power supply.

The motor is rated 5.6A, but it doesn't say whether that rating is for unipolar or bipolar parallel. I'm guessing bipolar parallel. You would use up to a 188k current limiting resistor. For half-coil (if I'm correct about current drawn by the motor), the motor would draw about 4A, so you would use up to a 62k resistor. Watch the motor's temperature. If the motor gets too hot, use a resistor with a LOWER value.
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  #81  
Old Mon 02 August 2010, 08:45
renraku
Just call me: renraku
 
rome
Italy
Quote:
Originally Posted by Richards View Post
The M1343020 motor has eight leads, which means that it has four coils. Coil A1 has the Red and the Yellow leads. Coil A2 has the Blue and the Black leads. Coil B1 has the White and the Orange leads. Coil B2 has the Brown and the Green leads.

To wire the motor half-coil, connect the Red wire to terminal 3 on the G203v (Coil A). Connect the Yellow wire to terminal 4 (Coil /A). Connect the White wire to terminal 5 (Coil B). Connect the Orange wire to terminal 6 (Coil /B).

To wire the motor bipolar parallel, connect the Red wire and the Blue wire to terminal 3. Connect the Yellow wire and the Black wire to terminal 4. Connect the White wire and the Brown wire to terminal 5. Connect the Orange wire and the Green wire to terminal 6.

The motor has 1.5mH inductance per coil, so I would use a 35VDC power supply.

The motor is rated 5.6A, but it doesn't say whether that rating is for unipolar or bipolar parallel. I'm guessing bipolar parallel. You would use up to a 188k current limiting resistor. For half-coil (if I'm correct about current drawn by the motor), the motor would draw about 4A, so you would use up to a 62k resistor. Watch the motor's temperature. If the motor gets too hot, use a resistor with a LOWER value.
------------------------------------------------------------
I thinking use unipolar mode 4 leads, i just bought resistor 200K on Gecko G203V i send you in attachement some pictures,
toroidal is 230V /50 HZ - 500VA
1 out 25V /20A
1 out 9V /1A
you can see others components
Could you check my pictures searching errors?
Under geckos driver there are 2 propeller fan
For finish machine i needs of emergency stop - pause - and start button
the right wiring to stepper motor to G203V
are:
RED TO PHASE A
YELLOW TO PHASE A-
WHITE TO PHASE B
ORANGE TO PHASE B-
CORRECT?
Thanks so much i hope to finish machine next mounth
unfortunately I do not understand electronics
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  #82  
Old Mon 02 August 2010, 11:57
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
You have correctly matched the motor's wires to the proper terminals on the G203v.

Because you have wired the motors half-coil (instead of bipolar parallel), you should use a lower value resistor. Instead of using a 200k resistor, try a 47k to 63k resistor. 47k is popular, so it should be easy to find.

You are daisy-chaining the power connections to the G203v. Instead of daisy-chaining the conntections, you should use a Star connection method. That means that all of the G203v Power + connections are directly connected to the power supply's (+) connector and that all of the G203v Power (-) connections are directly connected to the power supply's (-) connector. (I use a terminal block with jumpers to make that connection simpler.)

Pay close attention to your wire colors. The Yellow/Green color of the ground wire usually indicates that that conductor is AC Ground. When I use "standard" wire, I put a 1/2-inch length of colored heat shrink tubing close to the connection point. The color of the tubing indicates the conductor's function and/or voltage.

You're doing a very fine job of construction. Everything is neatly laid out. It's obvious that you're being very careful. Keep up the good work.
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  #83  
Old Mon 02 August 2010, 16:04
renraku
Just call me: renraku
 
rome
Italy
What is the correct method to working stepper motor ? unipolar or bipolar? I read the post uncorrect forum ? In your machine which kind of wiring have you 4 leads or 8 leads? Unipolar or bipolar
thanks, i hope to solve problems, i have fear to make irreparable errors
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  #84  
Old Mon 02 August 2010, 16:23
bradm
Just call me: Brad #10
 
Somerville(MA)
United States of America
Renraku, forget about unipolar; it doesn't apply to the Gecko drives. A unipolar drive uses 6 wires, not 4. The correct method is the method that matches the drive you have, which is bipolar in this case.

The choice you have to make is bipolar parallel, bipolar series, or bipolar half-coil. You probably don't want to use bipolar series, so that leaves the two options Mike pointed out. Your proposed wiring is bipolar half-coil, which will work just fine with the 47k resistor he stated.

8 wire motors exist because you can choose how you want to use the motor; they can be wired to be driven in any unipolar or bipolar configuration. Nobody has a machine with 8 leads, though; they have either 4 leads for bipolar, or 6 leads for unipolar. You then set the motor up accordingly.
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  #85  
Old Mon 02 August 2010, 16:59
renraku
Just call me: renraku
 
rome
Italy
Not is important for me methot unipolar or bipolar, just that it works well, ok, can you tell me what leads color i have to connect to geckos G203V and where, for example yellow to phase A etc. problem is: i don't know how connect stepper motor to the gecko, and i don't remember which post talking about a mathematical formula for resistor and total was 188K
This thing is setting a nightmare for me, wires, calculations do not want to think about how I set mach3 or I go crazy
thanks so much
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  #86  
Old Mon 02 August 2010, 18:19
bradm
Just call me: Brad #10
 
Somerville(MA)
United States of America
Renraku, as per the above:

RED TO PHASE A
YELLOW TO PHASE A-
WHITE TO PHASE B
ORANGE TO PHASE B-

and a 47k resistor.
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  #87  
Old Tue 03 August 2010, 01:12
renraku
Just call me: renraku
 
rome
Italy
thanks
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  #88  
Old Tue 03 August 2010, 04:14
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
Renraku,

Start simple. Connect only one G203v. Connect only one motor. Configure Mach 3 as that the one motor is connected to the X-axis. Experiment until you understand how to drive that one motor properly. Take lots of notes. See what happens when you connect Red to Phase A and Yellow to Phase /A, White TO Phase B and Orange to Phase /B. Then see what happens when you connect Yellow to A and Red to /A OR Orange to Phase B and White to Phase /B.

Don't rush.

Work slowly until you understand how to wire the motor and how to configure Mach 3.

If you can, use a 22k resistor for current limiting for a few hours. See how hot the motor gets when you run it at different speeds. Then, try a 47k resistor for a few hours. The motor will run much hotter, but it will also be able to move a bigger load.

Experiment carefully until you understand how the system works. Be sure to turn off the power each time you rewire anything.

That's the method that I followed when I tested a lot of different components. I started with one motor and changed things with that one motor until I understood how everything worked. It took time, but now I know what happens when I change the voltage, when I change the current available to the motor, when I change the leads of the motor, when I change the configuration in Mach 3. Now I know how fast I can run a motor. Now I know what happens when I change the acceleration (ramping) in Mach 3.

Everyone of us had to start at the beginning. There is a lot of information on the forum, but, if you're like me, you'll understand things better if you take the time to experiment for a few hours.
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  #89  
Old Tue 03 August 2010, 04:47
renraku
Just call me: renraku
 
rome
Italy
Thanks so much Richards, i'll do it, but it's all complicated to understanding for me, I hope to do no harm
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  #90  
Old Wed 04 August 2010, 03:31
renraku
Just call me: renraku
 
rome
Italy
I Richards, i've changed each wiring directly from Geckos to PMDX-135, and i've changed the resistors from 200K each to 47K each, is it better and correct? I send pictures by attachment, if is it correct could i try to connect to stepper motor and try to move the axis, and see if the machine works? Other question about bridge of motherboard PMDX-122: it's like i received it, i have to move some bridge or is ok ?
Thanks so much
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File Type: jpg 04082010333.jpg (159.5 KB, 891 views)
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