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IndustryArena Forum > CNC Electronics > Gecko Drives > Help with controller wiring - Gecko 202's
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  1. #1
    Join Date
    Mar 2004
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    636

    Help with controller wiring - Gecko 202's

    I wired up my router this week and was hoping to spin the motors this weekend for the first time, but can't get it working.

    I am using a 24V 25 A power supply, 3 gecko 202's, CNC4PC breakout board and an external 5V power supply from CNC4PC as well.

    When I turn the controller on, I get 24 v to the gecko's, 5 V to the breakout board. The red LED light is on on the Gecko's and BOB.

    Problem is that the motors wont lock up.

    I have the +5v from the CNC4PC power supply going to the geckos as required, but where do I hook up the ground side of this to? Could the fact that this is not hooked up yet be the cause of the motors not locking up?

    If not, what else should I check for?

    Thanks

    Dan
    Check out what I am working on at www.routerbitz.com!

  2. #2
    Join Date
    Jul 2005
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    668
    Quote Originally Posted by Hack

    I have the +5v from the CNC4PC power supply going to the geckos as required, but where do I hook up the ground side of this to? Could the fact that this is not hooked up yet be the cause of the motors not locking up?
    BINGO

    Connect the gound of the 5V supply to the ground of the BOB. You don't really have 5V unless there is a current return path.
    Steve
    DO SOMETHING, EVEN IF IT'S WRONG!

  3. #3
    Join Date
    Mar 2004
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    636

    Got it working ------Somewhat

    Well I got it working. Somewhat. I got all 3 axis to move by removing the current set resistors. Must have them figured wrong, but I figured that problem out at least. I will have to get some new resistors. All 3 motors lock up very strongly.

    Now a new problem. Only the Y axis runs properly. I have had it running over 300 IPM today with no problems. :banana: Stopped there but could have run it faster. I not to sure I will ever top it out at least until I get some limit switches installed.

    The X and Z axis work very ragged. Very choppy and the Z axis wont hadly even move. I disconnected everything on the Z axis. The motor is only turning the screw at this point and is unable to do so. I don't have the slides hooked up or a router of any kind to weight it down, yet it will still not turn properly. I feel as though I have eliminated any alignment issues by doing this as well. I am able to turn the screw freely when the steppers are not powered.

    I suspect the x axis is the same as it behaves similarly. Can anyone suggest any solution to this problem? How can I test to see if the motors are receiving current as needed. Which wires would I check?

    I have read about trim post adjustments, to adjust the midband compensation circuit. Not sure what this is, but could it be affecting 2 of the 3 motors?

    Thanks all.

    Dan
    Check out what I am working on at www.routerbitz.com!

  4. #4
    Join Date
    Mar 2003
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    35538
    Are you using Mach3? Try increasing the pulse width a little.
    Gerry

    UCCNC 2017 Screenset
    http://www.thecncwoodworker.com/2017.html

    Mach3 2010 Screenset
    http://www.thecncwoodworker.com/2010.html

    JointCAM - CNC Dovetails & Box Joints
    http://www.g-forcecnc.com/jointcam.html

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)

  5. #5
    Join Date
    Mar 2004
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    636

    Nope

    Currently using TurboCNC V4 just to get it running. Planned upgrade to Mach as finances allow.

    Dan
    Check out what I am working on at www.routerbitz.com!

  6. #6
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    Mar 2003
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    35538
    Still try increasing the pulse width. What's the accel set at? Are all axis set the same?
    Gerry

    UCCNC 2017 Screenset
    http://www.thecncwoodworker.com/2017.html

    Mach3 2010 Screenset
    http://www.thecncwoodworker.com/2010.html

    JointCAM - CNC Dovetails & Box Joints
    http://www.g-forcecnc.com/jointcam.html

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)

  7. #7
    Join Date
    Jul 2005
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    668
    I'm by no means an expert at this, but in the last week I set up my control box for 3 completely different motors: 4 wire, 8 wire and 6 wire and I had no problems to speak of. It was basically a no-brainer. Kudo's to the gecko ppl for what looks like a great product!

    I will say that I spent plenty of time making sure I knew exactly how everything was to be hooked up and why it was that way before the drives even got here.

    I think you have wiring problems, but no one can say for sure without at least a wiring diagram.

    I didn't have to dick with any pulse widths or such obscure configuration. If anything, the default config in TCNC was too conservative and slow. I could barely see the motors turn at first.

    Gerry, exactly which pulse width are you telling him to change? The only two signals that figure here are step and direction. Direction is not really a pulse, but more of a toggled value, so you must mean the step signal. When the motor is moving this signal is a pulse train whose width is inversely proportional to the frequency. To make the pulse wider you slow the frequency.
    Steve
    DO SOMETHING, EVEN IF IT'S WRONG!

  8. #8
    Join Date
    Mar 2003
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    35538
    I think that TurboCNC only has one pulse width setting.
    Gerry

    UCCNC 2017 Screenset
    http://www.thecncwoodworker.com/2017.html

    Mach3 2010 Screenset
    http://www.thecncwoodworker.com/2010.html

    JointCAM - CNC Dovetails & Box Joints
    http://www.g-forcecnc.com/jointcam.html

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)

  9. #9
    Join Date
    Mar 2003
    Posts
    35538
    Quote Originally Posted by Madclicker
    When the motor is moving this signal is a pulse train whose width is inversely proportional to the frequency. To make the pulse wider you slow the frequency.
    I don't think this is correct, but someone else will need to back me up on this. Are you saying if you double the pulse width, you cut your speed in half? I don't think so.
    Gerry

    UCCNC 2017 Screenset
    http://www.thecncwoodworker.com/2017.html

    Mach3 2010 Screenset
    http://www.thecncwoodworker.com/2010.html

    JointCAM - CNC Dovetails & Box Joints
    http://www.g-forcecnc.com/jointcam.html

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)

  10. #10
    Join Date
    Mar 2004
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    636

    Next idea?

    Well I checked the settings in turbocnc and made sure I matched the settings of the X & Z axis to the working Y axis. Made no difference. Currently set with the accel at 250, pulse width at 10 fast jog at 15000

    Checked to be sure I have 24 volts going into each gecko...I do.
    Checked to be sure I have 5V at pin 10 at each gecko.....I do.

    Is there a way to check how much current is going to the motors? I am wondering if I have a short between the geckos and steppers or something.

    Suggestions as to what to check next?

    I had emailed Art at CNC4PC to get some input on the breakout board and minipower supply I am using and I feel I have that stuff wired correctly. Perhaps an email to Mariss will be next to see if he has any ideas.

    Dan
    Check out what I am working on at www.routerbitz.com!

  11. #11
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    Jul 2005
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    What did you do with the 5V supply ground?
    Steve
    DO SOMETHING, EVEN IF IT'S WRONG!

  12. #12
    Join Date
    Mar 2004
    Posts
    636

    Nothing

    I did nothing withe 5V ground. In my email with Art (CNC4PC) he stated that it is not needed. The Y axis works wonderfully like this, Can't understand why it would make a differrence on the other 2 axis. I have tried taking the Ground on this circuit to the ground on the BOB and made no difference.

    Dan
    Check out what I am working on at www.routerbitz.com!

  13. #13
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    Oct 2004
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    742
    In TurboCNC make sure that you have the settings for the outputs set to "Active Low". Also the external 5 Volts + and - should go to the + and - on the breakout Bd. Verify the resistors installed for current.

    Set the pulse width to 3 or 4 uSeconds. Turn off the backlash setting or set to 0.

    Can you turn the leadscrew with your hand easily with the stepper attached, but without any power to the system? Under these conditions you should be able to turn the leadscrew easily.

    These are the items that come to mind.

    Jerry

  14. #14
    Join Date
    Mar 2004
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    636

    Thanks

    Yes I can turn the lead screws very easily with the motors off. Backlash setting is off. I will try and adjust the pulse to 3 or 4 tomarrow to see if that works.

    Dan
    Check out what I am working on at www.routerbitz.com!

  15. #15
    Join Date
    Mar 2004
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    636

    No luck yet

    Well I tried changing the pulse to 3 and to 4. Did not make a bit of difference unfortunately. Double checked all of my connections. didn't find any problems. Kind of lost at this point.

    I am thinking of swapping the steppers between the axis to see if the all work on the Y axis just to rule them out.

    Any other ideas?

    Dan
    Check out what I am working on at www.routerbitz.com!

  16. #16
    Join Date
    Oct 2004
    Posts
    742
    Quote Originally Posted by Hack
    Well I tried changing the pulse to 3 and to 4. Did not make a bit of difference unfortunately. Double checked all of my connections. didn't find any problems. Kind of lost at this point.

    I am thinking of swapping the steppers between the axis to see if the all work on the Y axis just to rule them out.

    Any other ideas?

    Dan
    Dan,
    The external 5 Volts should go to the + and - on the BOB. Without the (-) being connected, the drive does not see step or direction pulses.

    Also, if more than one axis jerks when you try to jog one motor, then you most likely have a loose motor wire on the axis you are trying to jog. I had this problem once. This can happen also if one of the motor coil wires is reversed.

    Keep us updated with what happens. Something does not sound right about the current resistors you have installed, especially if it works as well with the resistors removed. Increasing the resistor values increases the output current level. Try 33 K resistors. That will be ORANGE, ORANGE, ORANGE. This is the value I use for 3.5 amp motors. The steppers should work with this value. This is for testing only, unless this is the value needed. This value should not damage anything.

    Jerry

  17. #17
    It sounds like a Step/Direction interface problem. It's one we are seeing more and more as people migrate to newer PCs.

    Does the CNC4PC board have ICs marked with the characters "74ACT" somewhere in the part number. It doesn't matter what characters preceed or follow "74ACT", just that those characters must be printed on the ICs.

    Problem is new PCs (the ones that still have parallel ports) now use 3.3V signals instead of 5V. Second, the buffer ICs must be able to sink 16mA while meeting TTL spec voltage levels. The 74ACT logic series is the only modern one that meets both requirements. Otherwise, some drives will work, some will not but none are being driven correctly from the interface.

    Also check your step pulse polarity. The voltage on the G201/G202 STEP terminal must be +5V when you are sending no step pulses.

    If all else fails, feel free to call 1-714-771-1662 and ask for tech support. A real, live person will answer and pass you on to another real, live tech person. No music on hold (you won't be on hold long enough to enjoy it anyway), no recordings of option numbers to press and no recorded messages telling you "how important your call is to us" for 5,209th time.:-) If you are unlucky enough, you'll be passed on to yours truly if all other techs are busy on the phone.

    Mariss

  18. #18
    Join Date
    Oct 2004
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    742
    Dan,
    in TCNC load one of the demo programs and run it several times and see what happens. I know that if the start and acceleration settings are too high with some motors that the motors will jerk and whine but not really move.

    Set max frequency to 15,000
    Set Acceleration to about 250
    set start frequency around 500

    Any stepper should work with these settings.

    Verify that output pulses ON EACH AXIS is set to active low. (This has to be set for each axis). This is not contrary to the post from Mariss. His post relates to the voltage on the Gecko step input terminal with NO movement. Setting the output per above in my post will give the +5 Volts on the Gecko step input without movement, and a pulse train which might read as .3 Volts with movement.

    After this, give us an update as to results.

    Jerry

  19. #19
    Join Date
    Mar 2004
    Posts
    636

    Tried it - No results

    Well I tried a few things. First of all I swapped the Z and Y axis steppers just to make sure I didn't have a stepper problem. Z Stepper worked like a charm on the Y axis.

    Checked the BOB to verify that it does have the 74ACT on the IC's. It does.

    The PC is an old Pentium 200MMX so I doubt the issue is caused by a new computer.

    Changed the settings in TCNC as recommeded. No change.

    Checked the voltage on the step terminal. It was at 3.92. Is this adequate? It was measured with the the electronics powered up, but no movement of the steppers.

    To be truthful I think the next step is to connect some wires directly from the gecko to the steppers to rule out any connection possibilities. I have several "sections" of wiring. I haven't found any shorts, but I may be missing them. Motors turn barely, but are getting power because the lock up. Thats the only thing I can think of at this point.

    Any other suggestions?

    Thanks all

    Dan
    Check out what I am working on at www.routerbitz.com!

  20. #20
    3.92 volts is definitely a problem. It should be 5V or near-zero volts. Check the +5VDC supply to the breakout board.

    Mariss

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