. .

Hybrid View

Previous Post Previous Post   Next Post Next Post
  1. #1
    I have found the controller schematics here: http://www.cnc-router-store.com/wp-c...trolhy_eng.pdf

    The voltages all seem good at the 5V 12V +37V outputs, though the 37V is reading 33.5V

    What I have discovered is if I shake the PC end of the PP cable in the air, some of the axis move. When plugged into the computer (off & on) the motors are squealing and the controller relays for the spindle & coolant are buzzing, sometimes. When I remove the jumper wire from the controller back to the relays on the power board they stop okay so seem to be getting a pulsing signal from the computer end. When the PP cable is disconnected from the computer the motors are fine.

    I delved into the PC and I couldn't find the PP card in the device manager and pulling it out & replacing it with a boot in between, it's not recognising it. So I plugged into the onboard PP and changed the port address and the motors at least appeared to be responding to the jog controls, though not moving (pitch can in the sound). The sleep function appears to be working too.

    I swapped over to my spare pc which only has an onboard PP and I could get the axes to move roughly in the right direction, but with lots of noise & judder. They motors still squeal when stationary whether or not the PC is powered up.

    I have just ordered a new 25pin card & cable as a starting point. Does this sound like an issue with the PC now or do you still think that it could be controller related. I have checked for anything that could short out the control boards and all look clear. I gave it a light blast with the airline too.

  2. #2
    I usually get completely the wrong end of the stick but let's have a go.

    If you fitted a relay and everything went wrong even after that relay was removed...

    This would suggest the relay had no protection diode and what ever you were using to drive the relay also drove the thing that no longer works.

    You probably know about protection diodes but just in case. Current flows through the relay coil. A semiconductor device attempts to break the electrical circuit. The coil inductance requires that the current continues to flow, the volts go through the roof, the break down voltage of the semiconductor is exceeded and the magic smoke escapes. A protection diode across the relay coil allows the current to flow back through the coil until it dissipates.
    Last edited by Robin Hewitt; 21-02-2016 at 02:30 PM.

  3. #3
    Thanks Robin, never heard of protection diodes but there is a diode beside each relay on the power board:

    Click image for larger version. 

Name:	20160219_182002.jpg 
Views:	367 
Size:	481.6 KB 
ID:	17657

    I had taken leads from the coil pins of the existing relay on the underside of the power board to supply my additional relay. Maybe this extra load could overload the circuit, but the relays are still working okay using the manual override switches on the front panel. I didn't notice or smell any smoke at any point. Saying that I was flapping around at this point. Can't see any burn't components anywhere.

  4. #4
    Quick question. Does the 25pin port from the PC supply the 5V signals towards the controller only, or does the controller also have to send 5V signals back to the PC. I know that limit switches at least have to send a signal back in some form.

  5. #5
    The PP pins send and receive 5v signals depending on the pin. What worries me about this controller is that it has no opto isolation and so your computer is vulnerable. You should be glad that you have a PP card as it is easier to replace than a motherboard. Everything points to a spike going back to the PP. The pinout diagram shows the capabilities of each pin. How they are used depends on the controller. If it were my controller, I would replace the driver board with a BoB and three drivers, but it is a lot of work to cure what could be a simple fault.


  6. #6
    Thanks for that, I am hoping that it is just the PP card. Hopefully I will receive a new one by Tuesday. I remember when I could have popped over to PC world and picked one off the shelf but times seem to have changed.

    Replacing with a bob and drivers is my backup plan if all else fails. It is exactly as you put it so well: A lot of work over possibly over a simple fault. If I did end up going that way, with 2 steppers on the X axis, could I get away with 3 drivers or would I need 4?

    Cheers,

    Gavin

  7. #7
    +1 on the voltage spike possibility

    Quote Originally Posted by cropwell View Post
    The PP pins send and receive 5v signals depending on the pin.
    Or 3.3V for most modern cards and laptops.....

    Quote Originally Posted by artmin View Post
    I remember when I could have popped over to PC world and picked one off the shelf but times seem to have changed.
    Maplin still stock some but I'm not sure what bus types for and what voltage data levels.

    - Nick

  8. #8
    Quote Originally Posted by magicniner View Post
    +1 on the voltage spike possibility



    Or 3.3V for most modern cards and laptops.....



    Maplin still stock some but I'm not sure what bus types for and what voltage data levels.

    - Nick
    The PP cards generally are 5v logic.

    Sorry, you would need 4 drivers if you have a slaved X axis, I wasn't paying attention to the actuals, just the principles.

    What operating system are you using on the PC? Most of these PP cards have very old drivers. They work OK up to XP generally, but no later.

    I have got one of the PCI socket (not PCI express) PP cards (dual port) sat in a drawer and several new LPT leads, if you get stuck.

    Nick, Maplin used to be good, but it is just a toyshop now. Most of the gear you can get cheaper by up to 2/3 (that's a quarter of the price in pub talk) , though Maplin do take stuff back more readily.

    Cheers,

    Rob
    Last edited by cropwell; 21-02-2016 at 06:56 PM.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •