Need Help! G540 PWM VFD problem


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Thread: G540 PWM VFD problem

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    Default G540 PWM VFD problem

    Hello guys,

    Trying to manage an issue here. I have a g540 - mach3 - HY 1.5kw VFD setup which I hoped of controlling with mach3.

    So I've searched and found the homann designs wiring diagram which is awesome and i've wired everything according. I've added a 48v relay to switch the spindle on and off which works well through mach3. But no PWM at all. It stays near the max 24000 rpm of the spindle.

    So i've tried to power off the VFD to check voltages between pins 7 and 9 on gecko (which I assume gotta be 10v or near) and between 7 and 8 (at 50% should be 5v) but I have nothing. Switching the spindle on in mach3, the relay clicks aaand I don't have any reading between those pins at all, or some tiny mv. Well...

    I've powered the VFD on and measured those pins again. Wierdly enough between 7and 9 I have 7.8v, between 7 and 8 I have 9.8v and between 8 and 9 I have 2v. None of those voltages changes when I change PWM value in the mach3. I thought it's the g540's job to give the 10v signal to the VFD... Strange!

    Scratching my head here, don't know what to do really. I have one 48v PSU which powers the g540 and that's it.

    My settings in the mach3 : output1 on pin pin 17, spindle on pin 14, pulley 1, 24000, 1.

    Don't know what to do really here guys, please help!

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    Community Moderator Al_The_Man's Avatar
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    Default Re: G540 PWM VFD problem

    Did you use the OverKill 20amp relays on the Homann sheet?
    Also it does not show the required BEMF diodes (e.g.1n4007) across the coils, I have ran the G540 direct to VFD without relay.
    The G540 has digital to analogue convertor included to interface directly with the VFD
    Al.

    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.


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    Default Re: G540 PWM VFD problem

    Hello, no, i've used a less current one i think. It's rated 48v but 10a. So you telling me there is no need of it and i'm going directly from the pin5 to the FOR and that's it? I don't really know how one can not use relay as i'm not really good at electronics...

    I have it like this for now : https://designconceptschi.files.word...trol.jpg?w=648



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    Default Re: G540 PWM VFD problem

    Did you apply the BEMF diode across the coil, Google it if not sure.

    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
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    Default Re: G540 PWM VFD problem

    Here is the previous link I posted of one I did.
    https://www.cnczone.com/forums/spind...equipment.html
    Al.

    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.


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    Default Re: G540 PWM VFD problem

    I did not actually, I've wondered why it is here... Thank you for the link and your time man! You thing the problem is in the relay section of the shcematics?



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    Default Re: G540 PWM VFD problem

    Quote Originally Posted by sanekc View Post
    Hello guys,

    Trying to manage an issue here. I have a g540 - mach3 - HY 1.5kw VFD setup which I hoped of controlling with mach3.

    So I've searched and found the homann designs wiring diagram which is awesome and i've wired everything according. I've added a 48v relay to switch the spindle on and off which works well through mach3. But no PWM at all. It stays near the max 24000 rpm of the spindle.

    So i've tried to power off the VFD to check voltages between pins 7 and 9 on gecko (which I assume gotta be 10v or near) and between 7 and 8 (at 50% should be 5v) but I have nothing. Switching the spindle on in mach3, the relay clicks aaand I don't have any reading between those pins at all, or some tiny mv. Well...

    I've powered the VFD on and measured those pins again. Wierdly enough between 7and 9 I have 7.8v, between 7 and 8 I have 9.8v and between 8 and 9 I have 2v. None of those voltages changes when I change PWM value in the mach3. I thought it's the g540's job to give the 10v signal to the VFD... Strange!

    Scratching my head here, don't know what to do really. I have one 48v PSU which powers the g540 and that's it.

    My settings in the mach3 : output1 on pin pin 17, spindle on pin 14, pulley 1, 24000, 1.

    Don't know what to do really here guys, please help!
    Can you post a Photo did you take the 10v supply from the VFD Drive to Pin ( 9 ) and ACM to pin ( 7 )

    Mactec54


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    Default Re: G540 PWM VFD problem

    Hello! Thank you for your time. Well, I've connected pin7 to ACM (there are two of them), pin 8 to the VI and pin 9 to the +10v. relay goes from COM to the DCM and from NO to the FOR (on/off on VFD works well from mach3 and relay clicks like it should). No resistors nor led light.

    Maybe something wrong with gecko who knows, i've got it pretty early and didn't know how to wire things properly, maybe i've messed something on it. For now i've bought a linear 10k pot in case i'm not figuring the PWM side of the problem.

    Gonna post some pics when i'm in the shop!



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    Default Re: G540 PWM VFD problem

    Quote Originally Posted by mactec54 View Post
    Can you post a Photo did you take the 10v supply from the VFD Drive to Pin ( 9 ) and ACM to pin ( 7 )
    Hello! My answer is in the message above, forgot to quote



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    Default Re: G540 PWM VFD problem

    Quote Originally Posted by sanekc View Post
    Hello! My answer is in the message above, forgot to quote
    Try 100 in the PWM in Mach3 only pin 8 and 7 should show a change when you are in MDI and enter M3S12000 this should give you around 5v if it is working correct and you would need the VFD Drive to be ON to do this test as the G540 needs the 10v from the VFD Drive

    Mactec54


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    Default Re: G540 PWM VFD problem

    Quote Originally Posted by Al_The_Man View Post
    Did you apply the BEMF diode across the coil, Google it if not sure.
    The diodes are not required with the G540 as the FETs in the G540 have internal diodes, eliminating the need for additional diodes.

    Peter.


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    Homann Designs - http://www.homanndesigns.com


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    Default Re: G540 PWM VFD problem

    Quote Originally Posted by sanekc View Post
    Hello! Thank you for your time. Well, I've connected pin7 to ACM (there are two of them), pin 8 to the VI and pin 9 to the +10v. relay goes from COM to the DCM and from NO to the FOR (on/off on VFD works well from mach3 and relay clicks like it should). No resistors nor led light.

    Maybe something wrong with gecko who knows, i've got it pretty early and didn't know how to wire things properly, maybe i've messed something on it. For now i've bought a linear 10k pot in case i'm not figuring the PWM side of the problem.

    Gonna post some pics when i'm in the shop!
    The best way to get the G540 PWM set up with Mach3 is to connect a 9v battery in place of the VFD. That way you can test the output with out have to connect to and power up the VFD.

    Also, are you using a motion controller with Mach3 or are you using the parallel port?
    Cheers
    Peter.


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    Homann Designs - http://www.homanndesigns.com


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    Default Re: G540 PWM VFD problem

    Ok i'm an idiot, i've checked the pin to pin continuity with multimeter and my connections were wrong... Swapped 9 and 8 and it works! Thank you guys a lot.

    But! when i'm entering m3s12000, i'm getting 14000ish+ on my vfd screen. Anyone knows how to even it out a little, i'm not onto absolute precision? PD144 is 3000

    Didn't check the voltage between 7 and 8, been i a hurry, but will do it asap.



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    Default Re: G540 PWM VFD problem

    Quote Originally Posted by sanekc View Post
    Ok i'm an idiot, i've checked the pin to pin continuity with multimeter and my connections were wrong... Swapped 9 and 8 and it works! Thank you guys a lot.

    But! when i'm entering m3s12000, i'm getting 14000ish+ on my vfd screen. Anyone knows how to even it out a little, i'm not onto absolute precision? PD144 is 3000

    Didn't check the voltage between 7 and 8, been i a hurry, but will do it asap.
    You can play with the Pulley Raito and the PWM number both of these will change the output RPM result

    PD144=3000 has nothing to do with the PWM- Analog 0-10v speed control so needs to stay at 3000

    You must have a higher voltage than it needs at 12000 should be around 5v

    Mactec54


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    Default Re: G540 PWM VFD problem

    Quote Originally Posted by phomann View Post
    The diodes are not required with the G540 as the FETs in the G540 have internal diodes, eliminating the need for additional diodes.

    Peter.


    Sent from my iPhone using Tapatalk Pro


    These are normally for internal G540 protection.
    Diodes should be placed as close as possible to the coil for full effect, EMI can be radiated in the conductor of any significant length from G540 to the relay.
    The internal Mosfet diodes in the G540 are for the Mosfet protection and generally are of a lower value than the BEMF voltage level from the coil.

    CNC, Mechatronics Integration and Custom Machine Design

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    Default Re: G540 PWM VFD problem

    Quote Originally Posted by Al_The_Man View Post
    These are normally for internal G540 protection.
    Diodes should be placed as close as possible to the coil for full effect, EMI can be radiated in the conductor of any significant length from G540 to the relay.
    The internal Mosfet diodes in the G540 are for the Mosfet protection and generally are of a lower value than the BEMF voltage level from the coil.
    Geckodrive have stated external diodes are not necessary as the internal FET diodes are sufficient. I have sold 1000s of the G540. I haven’t seen any units being returned for repair with outputs being blown due to BEMF.
    I doesn’t hurt to have them but they are not necesssary.
    Cheers
    Peter



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    Default Re: G540 PWM VFD problem

    Quote Originally Posted by sanekc View Post
    Ok i'm an idiot, i've checked the pin to pin continuity with multimeter and my connections were wrong... Swapped 9 and 8 and it works! Thank you guys a lot.

    But! when i'm entering m3s12000, i'm getting 14000ish+ on my vfd screen. Anyone knows how to even it out a little, i'm not onto absolute precision? PD144 is 3000

    Didn't check the voltage between 7 and 8, been i a hurry, but will do it asap.
    Usually the actual speed is slightly less than the commanded speed as the PWM Voltage doesn’t quite reach the full 10V. Since you’re actual speed is higher than the Mach3 commanded speed, check that the max pulley speed in the Mach3 configuration is set to your maximum spindle speed (24000?)

    Also confirm what the maximum voltage you are getting out of the G540 on pin 8 (Vout). Say it is 9.7v, you may have a setting in your VFD that allows you to set the input control voltage (9.7V) that will produce the maximum spindle speed (24000rpm).

    Cheers
    Peter


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    Default Re: G540 PWM VFD problem

    Quote Originally Posted by phomann View Post
    Geckodrive have stated external diodes are not necessary as the internal FET diodes are sufficient. I have sold 1000s of the G540. I haven’t seen any units being returned for repair with outputs being blown due to BEMF.
    I doesn’t hurt to have them but they are not necesssary.
    Cheers
    Peter
    I have interfaced the Gecko G540 direct to the VFD PLC start input.
    The G540 is sink output, the VFD source input (opto).

    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.


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    Default Re: G540 PWM VFD problem

    Quote Originally Posted by Al_The_Man View Post
    I have interfaced the Gecko G540 direct to the VFD PLC start input.
    The G540 is sink output, the VFD source input (opto).
    Sure, you can do that as long as the VFD you are connecting to is compatible with the sinking output of the G540 (most new ones are).
    .
    My schematic includes a (OverKill 20amp) relay for a couple of reasons.

    1. Isolation - Without knowing what Spindle controller the user is connecting to the G540, I have to assume the worst. Apart from VFDs, user also use KBIC style spindle controllers, treadmill controllers that are not isolated and have mains voltage on their control inputs. If they try to connect these unisolated controllers directly to the G540 outputs as you do with a VFD, a catastrophic failure will occur destroying the spindle controller, G540 and possibly the PC.
    2. Power switching - When connecting to a VFD and switch a FWD control input, yes a 20A relay is overkill but;
      1. It works fine for switching these inputs.
      2. Provides isolation (if required)
      3. Is in a panel mount form factor so is easy for the hobbyist to mount.
      4. Allows the user to control a router or on/off style spindle motor with the relay
      5. At $8.50 it doesn't cost much more that a smaller spec'ed relay.


    I have to be conservative with the schematic as so many people reference it. I can't count the number of people who contact me as ask why they can't just feed the Estop into Pin 10 of the G540, rather than removing the mains power.

    When I build up a controller for a customer I use the following board to connect to their VFD. It has a couple of optical relays to do the switching of the control inputs. It fits into a DB9 enclosure allowing a standard serial cable to be use between the controller and the VFD.

    Cheers,

    Peter

    Attached Thumbnails Attached Thumbnails G540 PWM VFD problem-gc13f-png   G540 PWM VFD problem-gc13b-png  
    -------------------------------------------------
    Homann Designs - http://www.homanndesigns.com


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    Default Re: G540 PWM VFD problem

    I institute a power removal during E-stop as per N.A. regs for the VFD, some were concerned about the removal while the spindle was in operation, for this I included a VFD At-zero detect using one of the configured VFD outputs.
    This then satisfies the NFPA regs for a class 1, controlled stop.If the spindle is in motion.
    https://www.cnczone.com/forums/diy-c...ml#post2433070
    Post #12

    Last edited by Al_The_Man; 02-26-2021 at 12:07 AM.
    CNC, Mechatronics Integration and Custom Machine Design

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