584,833 active members*
5,796 visitors online*
Register for free
Login
Results 1 to 19 of 19
  1. #1
    Join Date
    Dec 2017
    Posts
    26

    home switch on stb4100

    i am trying to figure out how to wire up a limit/homing switches to my break out board (stb4100) the one i have has one connection for all homing and one connection for limits my question is does anyone have a pic of how to hook this up i have a induction proximity switch npn type with a power supply of 24 volts dc.

  2. #2
    Join Date
    Mar 2007
    Posts
    2083

    Re: home switch on stb4100

    I found this diagram online
    Attachment 426874

    the solution to your question depends on details like the part number of your proximity switch

    the LJ12A3-4-Z-BX proximity switches for example have a 10K pull up resistor built in
    that can cause problems when the switch is powered by a 24V supply and you are connecting it to a 5V logic circuit

    you may be able to parallel several proximity switches and
    connect the the black out wire to the stb4100 input and blue switch negative to the stb4100 input commom

    going by a photo of the stb4100 I have made a guess of the possible inputs and
    would add the diode shown on my diagram to stop the
    stb4100 input from going over +5V if you are using a proximity switch with a built in pull up resistor

    Click image for larger version. 

Name:	stb4100  connection to proximity switch.jpg 
Views:	39 
Size:	130.8 KB 
ID:	426876


    if you measure the open circuit voltage between the -V terminal used as the switch common and an input

    and the input opto-isolator input is powered by a 5V supply you should see 4 to 5V across the terminals and you should find 5V at the vias
    (plated through holes ) in this photo taken from the manual

    Attachment 426878

    if its +24V at the vias the resistors limiting the LED current will be about 1500 to 2200 ohms

    john

  3. #3
    Join Date
    Dec 2017
    Posts
    26

    Re: home switch on stb4100

    i am using urbest 8mm detecting distance sensor inductive proximity switch npn no dc 6-36v i am using a power supply of 24v dc i tested out tonight put the resistor on the hot lead (brown) to the input lead (black) the resistance was 22k ohms and it fried it up then i tried to hook up the resistor inline with the input lead (black) to the break out board side it dropped the voltage down only 1.3 volts my question is can i just use a 3 or 4 ohm resistor inline to get volt drop to 5v or will that not be sufficient and would eventually burn up also? will a diode stop this from happening . i also see the opto-isolator you included would that be enough to send a 5 volt signal without having to hook the resistors and diodes? i guess that takes place of soldering all the separate components into one board correct>

  4. #4
    Join Date
    Mar 2007
    Posts
    2083

    Re: home switch on stb4100

    I need more details of the proximity sensor than "urbest " and can't see how you burnt a 22k resistor with a 24V DC supply

    (current with resistor connected to 24V = 24/22000 = 0.00109 A
    power dissipated 0.00109 x 24 = 0.026W )

    can you measure the open circuit voltage between a stb4100 input terminal and the switch common V-

    Attachment 426898


    assuming your NPN proximity sensor uses the same wire colour coding as a LJ12A3_4_Z_BX

    can you measure the voltage between the black output wire and blue negative supply when the brown supply wire is connected to +24V

    whats the voltage when your proximity switch is on and when its off ?

    LJ12A3_4_Z_BX internal circuit
    Attachment 426900

    John

  5. #5
    Join Date
    Dec 2017
    Posts
    26

    Re: home switch on stb4100

    the power supply is 24v but the readable output is 22.3v it was a 22ku ohm resistor but i neglected to have a diode between the brown 24v to the black input lead the measured reading at the time before it burnt up was 21.6 v without being flagged it dropped down to .620v when flagged, i ordered last night the opto-isolator 24v to 5v will hook up the black lead to high side of isolator after going thur it will deliver 5v to input side that should do it? i see your schematic and see the diodes before the 10k ohm resistor to black wire and the the 2ohm resistor to input side of breakout board the opto-isolator looks like the diagram you have posted with the resists and diodes, with the same placements of both resistor and diodes only $7.00 per board figure i only need two input one for limits and one for homing. so hopefully this should remedy this issue

  6. #6
    Join Date
    Dec 2017
    Posts
    26

    Re: home switch on stb4100

    Attached Thumbnails Attached Thumbnails opto isolator.jpg  

  7. #7
    Join Date
    Mar 2007
    Posts
    2083

    Re: home switch on stb4100

    I am not convinced the 22K resistor is the correct value - 22000 ohms ( red red orange gold ? )

    what colours are the coloured bands around the resistor ?



    Did you measure the open circuit voltage between a stb4100 input terminal and the switch common V- ?

    if so what voltage did you measure ? (see first diagran in post 4 )


    with the proximity switch only connected to the 24V DC supply

    if your switch has an open collector output like this
    Attachment 426920

    the output should be 0V when its on and when its off

    the only time you should see the output at +24V is when a pullup resistor is connected between the output and the positive supply

    either like the 10K resistor inside the LJ12A3-4-Z-BX as shown in post 4

    or when you have an external pull up resistor

    thats why I need to know the part number to find the proximity switch data sheet


    knowing what the open circuit voltage between a stb4100 input terminal and the switch common V- is

    will determine how you can connect the proximity switch to the stb4100

    if the open circuit stb4100 voltage is +5V and the proximity switch output switches between 0V and +24V

    you can not connect the proximity switch output directly to the stb4100 input without further investigation !!!!



    you can only connect the proximity switch output directly to the stb4100 if

    1) the open circuit stb4100 voltage is +5V and the proximity switch output both on and off is 0V
    or
    2) the open circuit stb4100 voltage is 24V and the proximity switch output switches between 0V and +24V


    John

    PS
    just read post 6

    once I have the answers I will have a closer look at which version of the opto isolator board you need

  8. #8
    Join Date
    Dec 2017
    Posts
    26

    Re: home switch on stb4100

    the part number is LJ18A3-8-Z/BX

  9. #9
    Join Date
    Dec 2017
    Posts
    26

    Re: home switch on stb4100

    also the resistor colors were brown three black lines and then a brown line

  10. #10
    Join Date
    Mar 2007
    Posts
    2083

    Re: home switch on stb4100

    so the proximity switch is a LJ18A3-8-Z/BX and has an internal 10K pull up resistor

    the brown three black lines and then a brown lines decodes as 100 ohm 1%

    when connected across the +24V supply and the proximity switch output

    when the switch is on the current through the resistor will be

    24/100 = 0.24A

    power dissipated = 0.24 x 24 = 5.76 W !

    so any 1/2 or 1 W resistor will burn

    you do not need to add any pull up resistor


    the last piece of the puzzle

    what's the open circuit voltage between a stb4100 input terminal and the switch common V-

    Click image for larger version. 

Name:	open circuit  switch input voltage.jpg 
Views:	9 
Size:	50.8 KB 
ID:	426990

    John
    Attached Thumbnails Attached Thumbnails open circuit  switch input voltage.jpg  

  11. #11
    Join Date
    Mar 2007
    Posts
    2083

    Re: home switch on stb4100

    While waiting for the voltage measurement between the stb4100 input terminal and the switch common V-
    and if possible the current when an input is connected to the V- via your multi meter set to the 200 mA range

    I have been looking at the resistor values found on a 24V to 5V opto-isolator board

    and been speculating on the values to expect on a 24V to 24V board
    as I have not found one up to now

    Click image for larger version. 

Name:	24v to 5v opto isolator and predicted 24V to 24V board.jpg 
Views:	2 
Size:	72.6 KB 
ID:	427026

    John
    Attached Thumbnails Attached Thumbnails 24v to 5v opto isolator and predicted 24V to 24V board.jpg   24v to 5v opto isolator and predicted 24V to 24V board.jpg   24v to 5v opto isolator and predicted 24V to 24V board.jpg  

  12. #12
    Join Date
    Dec 2017
    Posts
    26

    Re: home switch on stb4100

    sorry john i was measuring the input and the brown leads off the proximity sensor wasn't getting what you wanted, the voltage off the breakout board from the neg lead on the board and input pin on board is 20.6 now does mean it can handle the 22 volt current or do i still need a resistor to lower voltage?
    i thank you for your patience and understanding you obviously gathered i know little to nothing about electronics

  13. #13
    Join Date
    Mar 2007
    Posts
    2083

    Re: home switch on stb4100

    That will indicate the stb4100 input terminal is connected to the +24V via a resistor and the LED inside the opti-isolator as in the last photo in post 2


    most of the missing 2V will be the forward volt drop across the LED


    That means you can connect the proximity sensor directly to the stb4100 input terminal

    when the proximity sensor switches on the NPN transistor will ground the stb4100 input terminal to the -24V supply
    and I would expect a current of about 10mA will flow out of the stb4100 input terminal and to ground via the proximity sensor

    you can check this by connecting a stb4100 input terminal to ground via a meter set to the 200mA range


    John

  14. #14
    Join Date
    Dec 2017
    Posts
    26

    Re: home switch on stb4100

    so i was worried about burning up the board for no reason i can connect it to the breakout board directly without doing any harm and don't need to drop voltage any the board with handle the voltage ?

  15. #15
    Join Date
    Mar 2007
    Posts
    2083

    Re: home switch on stb4100

    yes, this time

    with other breakout boards or motion controllers designed to work at 5V logic levels it could of been different


    without any detailed information thats why I wanted to know what the stb4100 input open circuit voltage was

    now we know both the stb4100 input circuit and the proximity sensor both work at 24V levels

    you can connect them together

    John

  16. #16
    Join Date
    Dec 2017
    Posts
    26

    Re: home switch on stb4100

    thanks you john for your understanding and patience i do appreciate the help and information

  17. #17
    Join Date
    Mar 2007
    Posts
    2083

    Re: home switch on stb4100

    thank you
    as long as you have your machine working

    this is what you should have when the proximity sensor is connected to a stb4100 input

    Click image for larger version. 

Name:	limit switch input circuit.jpg 
Views:	8 
Size:	53.2 KB 
ID:	427040

    without your measurements I could not be sure there was not a voltage regulator reducing the +24V to a lower voltage to power the opto-isolators

    John
    Attached Thumbnails Attached Thumbnails limit switch input circuit.jpg  

  18. #18
    Join Date
    Dec 2017
    Posts
    26

    Re: home switch on stb4100

    i have another question i hooked up the proximity sensor and its 20.6 and it drops down to .62 when its flagged but my question is on the breakout board it says there should be 0-10v at the dac and common part do you think it needs to be hooked up to the vfd to initiate the volt flow ? it also hook to the start and stop for the spindle?

  19. #19
    Join Date
    Mar 2007
    Posts
    2083

    Re: home switch on stb4100

    Once mach3 is setup and sending a PWM signal to the DAC (digital to analogue converter)

    you should see the 0 to 10V control voltage between the DAC and COM terminals

    Attachment 427076

    I have not found a high resolution photos to reverse engineer the board to be sure the COM and -V terminals are isolated or connected together

    but from this photo you can see the +V connection goes via a diode that prevents damage if the 24V supply connections are reversed

    ( the diode can be seen in the bottom left hand corner )


    In general board follows the design pattern followed by many breakout boards

    Having what I expect to be a ULN2801 transistor array in a socket is a great advantage

    the IC can easily replaced if you short circuit the +24V to one of the 4 outputs


    A week ago I replaced a damaged FET in a AXBB motion controller

    see posts 39 & 40

    AXBB charge pump fault - Page 4

    John

Similar Threads

  1. Replies: 2
    Last Post: 06-29-2018, 08:08 PM
  2. MACH 3, Warp9 smooth stepper, Leadshine mx4660 Limit switch home switch woes HELP
    By cabinman in forum Mach Software (ArtSoft software)
    Replies: 0
    Last Post: 01-14-2018, 08:26 PM
  3. limit switch and home switch setup
    By Runner4404spd in forum CNC Machine Related Electronics
    Replies: 0
    Last Post: 12-15-2005, 02:58 PM
  4. Limit Switch / Home Switch in Software
    By Sanghera in forum CNC Machine Related Electronics
    Replies: 6
    Last Post: 11-02-2004, 12:58 AM

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
  •