Need Help! Connect Opto Switch to Powered Input on BOB?


Results 1 to 13 of 13

Thread: Connect Opto Switch to Powered Input on BOB?

  1. #1
    Member
    Join Date
    Jun 2017
    Location
    United Kingdom
    Posts
    22
    Downloads
    0
    Uploads
    0

    Default Connect Opto Switch to Powered Input on BOB?

    Hi

    I've got a Boxford 160TCL that I'm converting to use Mach3, I am using this 5 axis breakout board:

    http://www.savebase.com/infobase/dow...kout_board.pdf

    I'm trying to connect an optical switch to it in order to use it as an index pulse. I want to get this right before I try to figure out how to connect the VFD which is another matter entirely, I will try hooking it up directly as the BOB can output 0-10v analogue but I may wind up using a spindle breakout board anyway.

    The problem I have is that the limit switch connections have 3.3v present even with nothing connected. With a test opto switch connected I get 3.4v untriggered and 3.9v triggered, Mach3 can't tell this is triggered. I'v tried to connect pull down resistors of both 22K and 220 ohm, neither of which work. I believe the problem is that the board has pullup resistors on the inputs (back of the board) but I want some help before I start snapping components off of the board.

    A mechanical switch connected triggers perfectly and is recognised by Mach3.

    I'm new to this stuff so speak slowly and don't use long words...

    Thanks in advance

    Similar Threads:


  2. #2
    Member john-100's Avatar
    Join Date
    Mar 2007
    Location
    uk
    Posts
    2083
    Downloads
    0
    Uploads
    0

    Default Re: Connect Opto Switch to Powered Input on BOB?

    a while ago I reverse engineered that BOB linked to , as it did not work as I expected

    Connect Opto Switch to Powered Input on BOB?-chinese-bob-jpg

    Connect Opto Switch to Powered Input on BOB?-chinese-breakout-board-jpg

    the input 74HC14 IC does not have +5V connected to pin 14 !!!!!!


    do you have any details of the optical switch ?

    the BOB linked to does not have any PWM to analogue converter for your VFD

    John



  3. #3
    Member
    Join Date
    Jun 2017
    Location
    United Kingdom
    Posts
    22
    Downloads
    0
    Uploads
    0

    Default Re: Connect Opto Switch to Powered Input on BOB?

    Hi John

    Thanks. I don't know much about the optical switch, it's one of a bunch I bought a while ago for my 3D printers. It's operating range is 3.3-5v but that's all I know. It has some supporting components on it's board including a very helpful LED.

    https://goo.gl/images/UBNBdX

    The optical switches built into the lathe (ideally the ones I want to use) seem to be working off of 12v but don't seem to trigger even when connected to the original board so I will be swapping those out for whatever I get working.

    Duly noted about the lack of d-a converter, I'll start searching for a spindle breakout board. I've not had any luck so far finding one, the chap at diycnc (Roy) seems to be too busy at the moment to make one of his famed boards.

    Pin 14, can I use that as an input? Mach3* and the BOB seem to both think it's a stepper output.

    *Mach3 doesn't list it as an input pin on the inputs page.



  4. #4
    Member john-100's Avatar
    Join Date
    Mar 2007
    Location
    uk
    Posts
    2083
    Downloads
    0
    Uploads
    0

    Default Re: Connect Opto Switch to Powered Input on BOB?

    only pins 10 , 11 , 12 ,13 & 15 are inputs

    if you had a second parallel printer port pins 2 to 9 could be set up as either 8 inputs or 8 outputs if you have a BOB like CNC4PC's C10


    looking at the photo of the photo switch you linked to
    I can only see a 1000 ohm resistor that looks like the current limiter for the LED indicator so I guess there are two more some where

    this is what I expect the board to be -
    (assuming the LED shows when the photo transistor is on and is not a 5v power indicator )
    Connect Opto Switch to Powered Input on BOB?-geeetech_img_5412-jpg


    when the photo transistor is illuminated by the LED in side the TSCT2103 the output should be between 0V and 0.7V

    when the photo transistor is dark (LED's light blocked off by an opaque flag and no stray light)
    the output should be over 3.5V


    John

    Last edited by john-100; 01-28-2018 at 06:38 PM.


  5. #5
    Member
    Join Date
    Jun 2017
    Location
    United Kingdom
    Posts
    22
    Downloads
    0
    Uploads
    0

    Default Re: Connect Opto Switch to Powered Input on BOB?

    Hi John

    Many thanks.

    There are indeed 2 more resistors on the back side of the switch.


    I can't find any more switches to test to see if this one's faulty, i.e. leaking it's supply voltage through the sense wire.

    Would I be better off getting something like this that seems to have an additional transistor on the board?



    I'm really not sure what to do.

    Thanks for all your help, I appreciate it.

    EDIT:

    Plan B would be to get this breakout board, it has the 0-10v output, and pray that the inputs aren't powered. For the price it could be worth a punt.
    5 Axis CNC Breakout Board Interface Adapter For Stepper Motor Driver + USB Cable | eBay

    EDIT EDIT:
    This video suggests that the inputs on the above breakout board are not powered.


    Attached Thumbnails Attached Thumbnails Connect Opto Switch to Powered Input on BOB?-dsc_0157-jpg   Connect Opto Switch to Powered Input on BOB?-dsc_0158-jpg   Connect Opto Switch to Powered Input on BOB?-s-l1600-9-jpg  
    Last edited by Ishtar; 01-29-2018 at 05:50 AM.


  6. #6
    Member john-100's Avatar
    Join Date
    Mar 2007
    Location
    uk
    Posts
    2083
    Downloads
    0
    Uploads
    0

    Default Re: Connect Opto Switch to Powered Input on BOB?

    Hi Ishtar

    this link in your first post -
    404 - File or directory not found.

    is not the board in your last post !!!

    this is the board in the video -
    Connect Opto Switch to Powered Input on BOB?-ebay-5-axis-cnc-bob-jpg

    this board does have a PWM to analogue 10V converter for your VFD

    on this BOB the LED inside of the opto-isolator is powered from a 10V regulator
    a 1K resistor limits the LED current when the switch grounds the input terminal

    depending on the meter you use
    the BOB input open circuit voltage will be about 9 to 10 V

    a simple micro switch will work OK but any electronic switch will need to have a NPN open collector output

    the opto interrupter switch you have has a 2K2 resistor (in parallel with the LED indicater + 1K resistor)
    between the +5V supply terminal and the NPN photo transistors collector

    when the transistor is switched off , some current will flow from the BOB's +10V supply and into the opto switches +5v supply !!!
    depending on the minimum current to ground the printer port needs to have to ground for a valid logic 0
    mach 3 may not see the switch operate

    Connect Opto Switch to Powered Input on BOB?-revised-opto-switch-jpg


    Connect Opto Switch to Powered Input on BOB?-revised-opto-switch-bob-input-jpg

    John

    Last edited by john-100; 01-29-2018 at 09:33 AM.


  7. #7
    Member
    Join Date
    Jun 2017
    Location
    United Kingdom
    Posts
    22
    Downloads
    0
    Uploads
    0

    Default Re: Connect Opto Switch to Powered Input on BOB?

    Hi John

    Thanks, the board in my last post is an alternative I'm considering, it's not the one I have currently. The one in the first post is correct.

    What do I need to do to get my original board to recognise the logic from my existing switch? Do I need to remove the 2K2 resistor on the switch?

    Thanks



  8. #8
    Member john-100's Avatar
    Join Date
    Mar 2007
    Location
    uk
    Posts
    2083
    Downloads
    0
    Uploads
    0

    Default Re: Connect Opto Switch to Powered Input on BOB?

    Hi Ishtar

    sorry I missed the alert to your post

    looking at the BOB & limit switch circuits you may have to remove the 2K2 resistor ( & possibly the LED or 1K resistor)

    as it is ,
    when the limit switches NPN photo transistor is OFF because the LED's light is blocked

    there may be enough current flowing from the BOB's +10V supply via the BOB's opto-isolators LED & 1K resistor plus the limit switch 2K2 resistor to the limit switches + 5V supply

    switching ON the the BOB's opto-isolator , so it will look like the limit switches photo-transistor is permanently switched ON

    John



  9. #9
    Member
    Join Date
    Jun 2017
    Location
    United Kingdom
    Posts
    22
    Downloads
    0
    Uploads
    0

    Default Re: Connect Opto Switch to Powered Input on BOB?

    Hi John

    I have a spare switch so I'll start removing components from the red switch.

    I have had successful triggers by using a separate transistor but I don't think it's switching fast enough to be used as an index pulse.

    The only thing to do is have a go and let you know.

    Thanks



  10. #10
    Member
    Join Date
    Jun 2017
    Location
    United Kingdom
    Posts
    22
    Downloads
    0
    Uploads
    0

    Default Re: Connect Opto Switch to Powered Input on BOB?

    Hi John

    Please may I tap into your font of knowledge once again? I have sorted the index pulse issue with a CNC4PC board, which does the same thing as my transistor but much more reliable and easier to configure.

    The BOB is outputting constantly from the 0-10v, around 8.5v. I can't seem to get Mach3 to operate the 0-10v at all. I have configured it as per the manual and a few other ways too. BOB is powered by 24v and the USB port.

    Thanks



  11. #11
    Member john-100's Avatar
    Join Date
    Mar 2007
    Location
    uk
    Posts
    2083
    Downloads
    0
    Uploads
    0

    Default Re: Connect Opto Switch to Powered Input on BOB?

    Hi Ishtar

    which CNC4PC board do you have ?



  12. #12
    Member
    Join Date
    Jun 2017
    Location
    United Kingdom
    Posts
    22
    Downloads
    0
    Uploads
    0

    Default

    Quote Originally Posted by john-100 View Post
    Hi Ishtar

    which CNC4PC board do you have ?
    I'm using the ST-V2 Chinese breakout board from earlier in the thread, and the C3 index board.

    EDIT The Bob was behaving like this even before I installed the C3



  13. #13
    Member john-100's Avatar
    Join Date
    Mar 2007
    Location
    uk
    Posts
    2083
    Downloads
    0
    Uploads
    0

    Default Re: Connect Opto Switch to Powered Input on BOB?

    Hi Ishtar
    now I have down loaded the ST-V2 manual
    I see they set the PWM pin 1 to active Low

    if my circuit diagram is correct
    I would of expected pin 1 should of been set as active high !
    So the output will be near 0V

    so far after another disastrous windows update
    its only taken me 10 days and 1.06 Tb to get back to some thing like normal

    for now I will have to download the Mach 3 manual to look at the set up page for the spindle

    John



Tags for this Thread

Posting Permissions

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


About CNCzone.com

    We are the largest and most active discussion forum for manufacturing industry. The site is 100% free to join and use, so join today!

Follow us on


Our Brands

Connect Opto Switch to Powered Input on BOB?

Connect Opto Switch to Powered Input on BOB?