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  1. #1
    Join Date
    Dec 2005
    Posts
    390

    Campbell Breakout Board

    What is the general concensus on using a breakout board with an IH CNC? Is there any reason (other than saving some cash) not too? Seems like there are many good reason to do so.

    Thanks

  2. #2
    Join Date
    Dec 2005
    Posts
    390
    Anyone here using this or any breakout board? I am leaning towards one with my kit arrive tomorrow but would like to know if there are any gotchas to be aware of when using the board from Bob.

    Thanks

  3. #3
    Join Date
    May 2005
    Posts
    52
    I used the CNC4PC board with mixed results. The first 1 had to go back because it didn't provide enough current to drive the Geckos all the time. The second one would only work on certain outputs, but it's working fine now. Don't know anything about the Bob Campbell board though, sorry. You definitely need a breakout board though, 1 to make the connections easier and 2 to protect your computer.

  4. #4
    Join Date
    Dec 2005
    Posts
    390
    Thanks for pointing out the CNC4PC board - I had not seen that one before. Quite a price difference between it and the Campbell board.

  5. #5
    Join Date
    May 2006
    Posts
    58
    i use two campbell boards and one of his relay boards with my ih cnc. can't recommend him enough. excellent product and... you do get what you pay for!
    dad used to say... "once is ignorance. the second time you're stupid!"

  6. #6
    Join Date
    Dec 2005
    Posts
    390
    That's what I needed to hear - got one ordered up.

    Thanks

  7. #7
    Join Date
    Jun 2005
    Posts
    208
    I have two PMDX-122 boards that I've been using for about a year without problems of any kind. Another user mentioned that his VFD created enough electrical noise when his PC was either off or not running Mach 3 to cause the outputs on his PMDX-122 to change state randomly. A suggested work-around is to add pull-up resistors to the input lines on the board (which would cost about $1.00 and take about five minutes if one end of each resistors were simply inserted into the wire terminals of a signal line and the other ends of all the resistors tied together and connected to a 5VDC line from the PMDX board).

  8. #8
    Join Date
    May 2005
    Posts
    2502
    Richards brings up an interesting thought. Be really careful around a CNC machine. Don't have the drivers powered up if there is no PC in charge. A lot of these breakout boards have a safety charge pump circuit for that purpose.

    Alternatively, it isn't that hard to wire a circuit that will not apply power to your motors until your PC or other front end controller (mine is a GRex) has had time to boot up. Shut down said PC or front end, and the power goes off for the motors.

    I used a delay-on-make relay for my circuit. This is a handy little relay that waits a specified amount of time after it "sees" lline voltage before letting it through. You can set the interval from a few seconds up to minutes. That relay gets the line voltage going into my GRex (or your PC), waits long enough for it to boot, and then sends it on to power up the motor DC supply.

    Be sure if you are going to cut power you do it in the right way so as not to blow your Geckos--you want to just cut the power to the DC supply. The filter capacitor will let it down gently. Don't just stick a relay (or a fuse for that matter) between your Geckos and the motors.

    I've also wired a hard E-Stop (actually a couple) between this delay on make relay and the line voltage. If I hit one, it also pulls the power to the motors. Lastly, my spindle gets its juice here too. I'm gonna be hitting those E-Stops any time I have to reach my hands into that machine to change cutters or whatever--I want to know without any doubts there is no juice to those motors.

    Just a thought!

    Best,

    BW

  9. #9
    Join Date
    Dec 2005
    Posts
    390
    I started wiring an IH CNC kit to a Campbell board and wondered if someone would explain how to power the limit switches. Aaron's wiring diagram calls for 5V but I don't see a dedicated 5V supply on the board for this. Perhaps I can use the 5V that feeds the geckos? Alternatively perhaps I could put a resister to cut the voltage down... What do you think?

    Thanks

  10. #10
    Join Date
    Jun 2005
    Posts
    208
    I'm extremely conservative when it comes to hooking up devices. In my prior life, I designed, programmed and installed process control computers in the photo industry to run the Kodak-S series printers found in most professional photo labs (before the digital photo revolution made my services as valuable as a buggy whip manufacturer). I always use opto-isolators whenever interfacing anything into a control board. That means that the limit switches would have their own power supply and that the only connection between them and the controller board (breakout board) would be light pulses. The inexpensive Texas instruments TIL-111 series of opto-isolators can usually be purchased for a few cents each. My favorite is the Opto-22 G4 modules that run about $15 each for input modules, although they require a 'rack' for another $70 or so.

    Connecting signal lines on a machine that has stepper/servo motors, VFDs and assorted other mechanical/electrical devices directly to a controller board is just asking for problems, either now, or sometime down the road. An extra $10 to $250 dollars up front to do things right will keep you safe and sane.

    Some breakout boards are already opto-isolated. (I'm not familiar with the Campbell board - which might work perfectly right out of the box.) If that's the case, then you would only have to add a power supply that is independant of the controller's power supply to keep things isolated.

  11. #11
    Join Date
    Dec 2005
    Posts
    390
    Anyone know how to interface the Geckos so that a fault causes Mach3 to stop? The behavior currently is that the Gecko faults but Mach thinks the moter is still moving.

  12. #12
    Join Date
    May 2005
    Posts
    2502
    I'm assuming by "fault" you mean a servo fault and you are using a Gecko 320 to drive it. The doc for that drive (http://www.geckodrive.com/photos/G320_REV-4_MANUAL.pdf) discusses how to access its ERROR output and still allow the drive to be reset via a switch. If you've got an output, and enough inputs on your breakout card, you can presumably send the result back to Mach and set up Mach to shut things down on a fault, much as it would if you hit a limit switch. This will require a bit of macro work as well as a bit of electronics, so you'd best get some help on the Mach and Gecko support boards if you really want to pursue the option.

    Best,

    BW

  13. #13
    Join Date
    Jun 2005
    Posts
    1015
    http://www.aree.com/gecko/err.html

    i've got this one and i'm running it with the cnc4pc board.

  14. #14
    Join Date
    Dec 2005
    Posts
    390
    Runner - That board looks like just the thing! I am curious about the recommended use of relays that the board's documentation suggests. I thought I had read that abruptly killing the voltage to the geckos can be damaging and hence the power supplies have a cap/bleed off resistor for cushion when power is lost.

  15. #15
    Join Date
    Dec 2005
    Posts
    390
    I started hooking the IH limit switches up tonight to a Sound Logic breakout board and can only manage to get either the home or the limit on each axis to trigger. There are four wires coming from each limit switch: common, power, sensor 1, ans sensor 2. Inside the limit switch two Fairchild H22LTB optical modules are used. I first attached the power, common, and sensor 1 to the home pins. After configuring Mach3 a little I was able to trigger home. I then attached sensor 2 lead to a set of limit signal pin leaving the power and common connections free on the limit pins. After doing that neither limit could be triggered in Mach3. Detaching the home sensor lead now allowed the limit to work. I also tried attaching both sensors to the home through diodes without success. In short I only seem to be able to attach only a single limit switch on each axis. Anyone have an idea of what might be happening here?

    Thanks

  16. #16
    Join Date
    Dec 2005
    Posts
    390
    Well, after more tinkering I managed to get it to work and have sent what I did to Cullins for him to verify. Basically I added a diode to each side of the limit switch, tied the other end of the diodes together to the Sig line on the limit input to the board, and added a resister between Sig and Gnd to force a natively low level. It seems the Sound Logic board expects the limit switches to sink the Sig current to low when not triggered and source it high when triggered. When both sides of the limit switch are connected to the single input on the board they sink each other low and a high value is never seen. By adding the diodes they don't sink each other but the normal (unconnected) level and the level when the limit switch is tripped are not very different (but each side of the switch is distinguishable). Adding the resister sets the default level low and each side of the limit switch is easily distinguished. It now works and so far no smoke has been seen

  17. #17
    Join Date
    Feb 2006
    Posts
    794
    Wildcat, This is some very good info that i will appreciate quite soon, It sounds exactly like what Aaron had me do with them anyway, but in tieing it in to "P" port signal. Allthough the opt limits don't need the breakout and neither do the Gecko's, I am opting for the cambell combo board as well just to clean things up a bit and link with my L200 vfd and coolant pump. I tried to do it with the cnc4pc spindle and relay, but have nothing good to say (period). My thought here is I'd like to see a schematic of this hookup of yours because i know for a fact i'll need the same for my machine ! I think I can see what your saying but when it comes to electronics, A picture is worth a lot ! and Information is Gold ! I may be great at mechanical and alright at machining (my vocation) But not very advanced (elementry) with electronics. I just want to get this machine solid so i can sit down and spend some time with turbocad/cam 12 and learn how to get along with it !
    Don
    IH v-3 early model owner

  18. #18
    Join Date
    Apr 2005
    Posts
    1268
    Hey Guys;
    Just a quick peek at the above for this fast moving friday, but did I miss something?? What happened to the old fashion charge pump as a system monitor? They are inexpensive and will not allow the system to fire (relay lockout) unless mach is outputing a solid freq on pin 17. I use them on all my systems and when I have a computer problem, the system HV drops out a as a safety and the motors stop. If this has been addressed, just disregard.
    Bill
    billyjack
    Helicopter def. = Bunch of spare parts flying in close formation! USAF 1974 ;>)

  19. #19
    Join Date
    Feb 2006
    Posts
    794
    Bill, charge pump is part of the board but not the discussion !
    Don
    IH v-3 early model owner

  20. #20
    Join Date
    Dec 2005
    Posts
    390
    Cruiser - I never made a full schematic. Actually I am still modifying my electronics but below is how I interfaced the IH limit switches to the Campbell board. This "circuit" must be replicated for each limit so you will need six diodes and 3 resisters. You can interface this to either the home or the limit pins on the breakout board - they are tied together on the board. The exact diode is not too important - I used 1N4006 since I had six of those. Aaron sends three 1n4004 with the kit so if you can find three more... I chose a 270 ohm resister as it provided a nice differential between low and high and kept low to less than a volt. Also, I tied all the shields together and grounded them. Also, for some reason, if you wire the Geckos as Aaron has in his schematic and then tie the Geckos to the breakout board the motors turn the "wrong direction." You may need to reverse the leds and encoder phase connections. Please clarify if you need a full schematic and I will do a better job drawing one up.

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