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IndustryArena Forum > Machine Controllers Software and Solutions > Mach Software (ArtSoft software) > Machines running Mach Software > Mach3 not controlling PWM of BL-USBMach Break out Board of Chinese CNC3040 Machine
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  1. #1

    Mach3 not controlling PWM of BL-USBMach Break out Board of Chinese CNC3040 Machine

    I got a cheap three axis Chinese CNC3040 wood cnc machine that uses
    1. A BL-USBMach Board
    2. Three Steper motor Drivers
    3. One PWM Driver Board which Drives the 400W Spindle motor.

    I have been able to configure the Machine using MACH3 software and I have a good control for the X, Y and Z axis.
    THE PROBLEM:
    The Spindle Motor is NOT connected to the BL-USBMach Board even though the Board has both a PWM and VFD output. The Spindle motor was configured to be controlled manually from a potential divider knob.

    I have tried to modify it by taking the (0-5V) input from the POT to the PWM output of the BL_USBMach Board BUT I dont have any Response. Please if you are familiar with the BL-USBMach BOB let me have your help.
    Thanks.

    I have gone to to MACH3 software to configure
    1. Motor Output as:
    Spindle=Enable
    Step Pin#=17
    Dir Pin#=1
    2. Output Signals as:
    Output#1+Enabled
    Port Number=1
    Pin Number=17
    3. Spindle Setup
    Relay Control=Disabled
    Motor Control: Use Spindle Motor Out and PWM Control=Checked

  2. #2

    Re: Mach3 not controlling PWM of BL-USBMach Break out Board of Chinese CNC3040 Machi

    For anyone in a similar situation, I have a LY Group 1.5kW CNC kit that came fully assembled and it is set up the same way. I've probed the spindle output of the BL-USBMach board with a scope, and no alteration of the settings will result in a PWM signal emitted from the board. The board has a 4-pin spindle connection, of which only one signal pin and one ground pin are connected. The other two unwired pins probe to noisy versions of the signal pin or ground.

    The signal pin is 1V when the spindle is ON, and GND when the spindle is OFF. Interestingly, when the board starts up and before the BL-USBMach driver has been loaded, the signal pin is +10V.

    The potentiometer is fed straight to the VFD board and since this VFD is not a standard terminal block wiring like a HuanYang unit or any other common VFD, I am not going to mess with it. I also don't have a manual for it. I don't know how they've wired the potentiometer signal into the VFD, and don't have any reasonable indication that the BL-USBMach would be able to give it a proper signal anyway.

    So, looks like these are manual control only.

  3. #3
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    Re: Mach3 not controlling PWM of BL-USBMach Break out Board of Chinese CNC3040 Machi

    Quote Originally Posted by Hermitude View Post
    For anyone in a similar situation, I have a LY Group 1.5kW CNC kit that came fully assembled and it is set up the same way. I've probed the spindle output of the BL-USBMach board with a scope, and no alteration of the settings will result in a PWM signal emitted from the board. The board has a 4-pin spindle connection, of which only one signal pin and one ground pin are connected. The other two unwired pins probe to noisy versions of the signal pin or ground.

    The signal pin is 1V when the spindle is ON, and GND when the spindle is OFF. Interestingly, when the board starts up and before the BL-USBMach driver has been loaded, the signal pin is +10V.

    The potentiometer is fed straight to the VFD board and since this VFD is not a standard terminal block wiring like a HuanYang unit or any other common VFD, I am not going to mess with it. I also don't have a manual for it. I don't know how they've wired the potentiometer signal into the VFD, and don't have any reasonable indication that the BL-USBMach would be able to give it a proper signal anyway.

    So, looks like these are manual control only.
    The manual is total crap. Tells you everything completely wrong and puts nearly all ports/pins as 0 in Mach.

    Need to find out which pin is what number on the board. Simple as that. If you figure that out you'll crack it straight away. You could use a relay to trigger each one until you know their numbers.

    So far on boards I've used the spindle was:
    Pin 1 is step (0-10v pwm)
    Pin 17 is dir (fwd / rev)

    Should be able to use
    FWD as dir to activate a relay (on fwd/off rev) or vice versa.
    AV as 0-10v +ve
    GND as 0-10v-/gnd

    or iuse PWM via external converter for the 0-10v

    What pin no's are your steppers for curiosity?

  4. #4
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    Re: Mach3 not controlling PWM of BL-USBMach Break out Board of Chinese CNC3040 Machi

    Quote Originally Posted by Hermitude View Post

    The signal pin is 1V when the spindle is ON, and GND when the spindle is OFF. Interestingly, when the board starts up and before the BL-USBMach driver has been loaded, the signal pin is +10V.
    So, looks like these are manual control only.
    That may be the 0-10v output pin (whichever number it is)
    Disconnect inverter and get your voltage tester.
    Try THAT pin as pwm (spindle step) instead.
    If it's 10v when spindle isn't running, change active low/high level, it should go back to 0v and work properly with spindle on.
    If that don't work it's not the right pin number (again).

    Your problem is the board doesn't tell you which pins are which number.

  5. #5
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    Re: Mach3 not controlling PWM of BL-USBMach Break out Board of Chinese CNC3040 Machi

    If this is the correct board:
    https://artofcircuits.com/product/5-...card-for-mach3
    There is a XML config file you can download that contains the correct setup for Mach3 (apparently)
    Just add that to Mach3 folder and it should set all the pins etc correctly.

  6. #6

    Re: Mach3 not controlling PWM of BL-USBMach Break out Board of Chinese CNC3040 Machi

    Quote Originally Posted by dazp1976 View Post
    That may be the 0-10v output pin (whichever number it is)
    Disconnect inverter and get your voltage tester.
    Try THAT pin as pwm (spindle step) instead.
    If it's 10v when spindle isn't running, change active low/high level, it should go back to 0v and work properly with spindle on.
    If that don't work it's not the right pin number (again).

    Your problem is the board doesn't tell you which pins are which number.
    The thing is, the spindle will run at 24000rpm when that pin is only 1V. The 10V signal only occurs before BL-USBMach has come up (ie: before Mach3 is started).

    My theory is that the board designer decided to provide the VFD's 10V reference signal on that pin by default. It would be intended for 0-10V operation. But some later engineer (firmware developer writing the driver or system engineer connecting the VFD) decided to use that pin as a crude on/off switch. The system engineer wired an external potentiometer from the front of the case to the VFD's usual 0-10V pins, so as long as the pot is there, there's no safe way for the controller to use that facility nor to use a competing PWM signal.

    You're right, I could disconnect the VFD from it and probe the controller further, but it's tough to get into that box and at this point I'm a bit fed up with it. I can control spindle speed with the external pot that they provide (grumble).

    All of this is going to be irrelevant when I replace the controller. View my build thread:
    https://www.cnczone.com/forums/chine...-software.html

    Quote Originally Posted by dazp1976 View Post
    If this is the correct board:
    That's definitely a reference version of the board that I have. The usb driver is almost the same (mine is v2.1). Mine also has completely different connectors. For example, it has really big chunky (and likely also obsolete) board-to-board connectors for each of the stepper drivers plugged into it. The driver boards have no other connections themselves and so each stepper's signals and power rails have to be fed through those connectors.

  7. #7

    Re: Mach3 not controlling PWM of BL-USBMach Break out Board of Chinese CNC3040 Machi

    Quote Originally Posted by dazp1976 View Post
    What pin no's are your steppers for curiosity?
    Well, I've mapped the parallel port but there's no numbering on the board itself. It's at https://www.cnczone.com/forums/chine...-software.html

    The only signal connections between the controller and VFD are a GND and that one 1V signal pin I mentioned. So likely no DIR pin available. That signal only ever seems to perform as a crude on/off. It is always 0V off / 1V on during normal Mach3 operation. That's with an oscilloscope, not a multimeter. There is no PWM/square wave component to it.

  8. #8
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    Re: Mach3 not controlling PWM of BL-USBMach Break out Board of Chinese CNC3040 Machi

    Quote Originally Posted by Hermitude View Post
    Well, I've mapped the parallel port but there's no numbering on the board itself. It's at https://www.cnczone.com/forums/chine...-software.html

    The only signal connections between the controller and VFD are a GND and that one 1V signal pin I mentioned. So likely no DIR pin available. That signal only ever seems to perform as a crude on/off. It is always 0V off / 1V on during normal Mach3 operation. That's with an oscilloscope, not a multimeter. There is no PWM/square wave component to it.
    Looks like you have 4 pins to each stepper?. Well.
    I think you are confusing the 5v+/- terminals as all different pins.
    There is actually only 2 per stepper for pul/dir. Then 1 +ve terminal and 1 -ve terminal for Enable terminals on ALL drivers. For instance for 3 steppers you use 8 pins. 3 each pul/dir & 2 for all +/- 5v power.

    If you are wired common anode then it's as follows:
    5v+ to all these in parallel...... Enbl+ / Pul+ / Dir+.
    5v- to...... Enbl- (or assign a pin to it and connect all drivers Enbl- to same pin.
    Pin xx to..... Pul-
    Pin xx to..... Dir-

    If you are wired common cathode
    5v- to all these in parallel...... Enbl- / Pul- / Dir-.
    5v+ to...... Enbl+ (or assign a pin to it and connect all drivers Enbl- to same pin.
    Pin xx to..... Pul+
    Pin xx to..... Dir+

    My basic parallel port map is as follows:
    1= pwm
    pwm GND is not classed as a pin (it's taken from pins 18-25)
    2= X pul
    3= X dir
    4= Y pul
    5= Y dir
    6= Z pul
    7= Z dir
    8= A pul
    9= A dir
    10= estop
    11= tool probe
    12= X limit
    13= Y limit
    14= Stepper driver enable. Same pin goes to ALL drivers.
    15= Z limit
    Limit GND is not classed as a pin (it's taken from pins 18-25)
    16= B pul
    17= B dir or spindle relay ( depending on jumper setting
    5V+ is not classed as a pin. Comes from psu. Same feed goes to ALL drivers.
    5V-/gnd is not classed as a pin. Comes from psu. Same feed goes to ALL drivers.

    That's the normal 12 outputs, 5 inputs, the rest are gnd.

  9. #9

    Re: Mach3 not controlling PWM of BL-USBMach Break out Board of Chinese CNC3040 Machi

    Quote Originally Posted by dazp1976 View Post
    Looks like you have 4 pins to each stepper?. Well.
    I think you are confusing the 5v+/- terminals as all different pins.
    There is actually only 2 per stepper for pul/dir. Then 1 +ve terminal and 1 -ve terminal for Enable terminals on ALL drivers. For instance for 3 steppers you use 8 pins. 3 each pul/dir & 2 for all +/- 5v power.
    No, no. The pin mapping in that other post is just a different parallel port than what you are used to seeing. This machine I have runs a parallel port / cable between the controller box and the cnc frame itself. That cable contains each stepper's bipolar power lines and some NO limit switches.

    I understand what you are referring to. The stepper EN/DIR/PUL logic signals which would normally run between the controller board and the stepper drivers. On this machine, the stepper driver boards are simply plugged into the controller board via some board-to-board edge connectors.

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