Octocoupler and LJ12A3-4-Z/BX



  • Hi,
    So I've tried different sensors, and the only success i've had is with the BLtouch(a fake one) attached to a 240ohm resistor.

    I am now trying one of these sensors again LJ12A3-4-Z/BX, with one of these octocoupler 12V 1 Channel Relay Module With OPTO Isolation Support High or Low Level Trigger,
    as shown in this image-[img]https://i.imgur.com/FlVRQ81.png[/img]

    the features of my one are as follows:

    • 12V 1 Channel Relay Module With OPTO Isolation Support High or Low Level Trigger Product description´╝Ü
      1. The module uses genuine quality relay , normally open interfaces Maximum load : AC 250V/10A, DC 30V/10A;
      1. Using SMD OPTOCOUPLER isolation , driving ability , stable performance ; trigger current 5mA;
      1. The module voltage is 12V ;
      1. The module can be set to high or low triggered by jumper ;
      1. Fault-tolerant design , even if the control line is broken , the relay will not operate ;
      1. The power indicator ( green ) , relay status indicator ( red )
      1. Interface design humane, all interfaces can be connected directly via terminal wiring leads , very convenient
      1. Module size : 50mm * 26mm * 18.5mm ( L * W * H )
      1. Has four mounting bolts holes , hole 3.1mm, 44.5mm * 20.5mm pitch
    • Interface :
      1. DC +: positive power supply 12V
      1. DC-: negative power connection
      1. IN: can be high or low level control relay
    • Relay outputs :
      1. NO: normally open relay interface, the relay before the vacant after the pull shorted with COM
      1. COM: Common Interface Relays
      1. NC: normally closed relay interface relay shorted with COM ago , after the pull- vacant
    • High and low trigger selection ends :
    • 1 short jumper with LOW triggered when connected ;
    • 2 When the jumper is high with high short trigger .

    Would this octocoupler and the LJ12A3-4-Z/BX work? i.e. connect it as shown in the image.

    [img]https://i.imgur.com/FlVRQ81.png[/img]

    Its annoying as i am still looking for the most reliable and consistent sensor possible, and would like to use the most common style of sensor for my printer.

    Another question, what will happen if I buy the genuine BLtouch, would it work plug and play, as the wiring diagram mentions that no resistor is needed. [img]https://i.imgur.com/wl44jVx.jpg[/img]

    As when I purchased this version of the bltouch from amazon, I had to wire the 240ohm resistor so that duet can pick up the signal
    https://www.amazon.co.uk/BIQU-Leveling-Sensor-BL-Rostock-Printer/dp/B0748FJ48N/ref=sr_1_1?ie=UTF8&qid=1536674872&sr=8-1&keywords=bltouch

    Please Help



  • I been using this one: https://www.amazon.com/gp/product/B00MMW0XWY

    I don't see a relay or jumper on the one you have an image for, it doesn't show the number of connections your description has.

    See the duet documentation for the bltouch: .https://duet3d.dozuki.com/Wiki/Connecting_a_Z_probe scroll down to bltouch.



  • @stephen6309 said in Octocoupler and LJ12A3-4-Z/BX:

    I been using this one: https://www.amazon.com/gp/product/B00MMW0XWY

    I don't see a relay or jumper on the one you have an image for, it doesn't show the number of connections your description has.

    Does this way of using and connecting the sensor work flawlessly.
    How accurate is the bed leveling, and its repetition as a z endstop
    Which sensor do you have inductive or capacitive

    and finally how have you got it connected, the one i've purchased is exactly the same one as yours



  • LJ18A3-8-Z/AX Inductive Proximity Sensor Switch, mine has a longer detection distance of 8mm.

    Relay output: COM and NC to the E0 endstop

    Input:
    DC+ has 12v + and sensor +
    DC-: 12v - and sensor -
    IN: has the signal output wire of the sensor

    Jumper set to energize the relay when the sensor is triggered.

    Z probe is setup up as a endstop switch on E0 endstop input.

    Still using the old gcode settings.
    M558 P4 X0 Y0 Z1 H3 F200 T5000 R0 ; proximity probe via relay on E0

    G31 P500 X-36 Y8 Z0.8 ; (proximity) set threshold and offsets - z offset is last one - increase to get closer to the bed
    This is my default z offset. I use a macros to set it for the filament. PLA and PETG need a different offset due to the temperature difference. I put the appropriate G31 line in each.



  • I am running a genuine bl touch. Go to their website and they list the only two genuine sellers on the likes of AliExpress plus other sellers around the world. You do not need the resistor as there is a small track you cut to turn it to 3.3v logic

    Regards
    Sam



  • I've tried all three different resistors with an LJ style sensor neither of them worked as needed i.e. the sensor didn't stop the Z Axis from crashing into the bed.

    My wiring and soldering was done correctly, however neither worked.

    In-terms of the BLTouch which worked well until the wiring was incorrectly, didn't give me satisfactory bed leveling.

    Still looking for the best option, for auto bed leveling with no flath and hassle.

    as the bed leveling with the duet has made me bold



  • How often do you have to use baby stepping with the octocoupler.



  • This post is deleted!


  • @stephen6309 said in Octocoupler and LJ12A3-4-Z/BX:

    LJ18A3-8-Z/AX Inductive Proximity Sensor Switch, mine has a longer detection distance of 8mm.

    Relay output: COM and NC to the E0 endstop

    Input:
    DC+ has 12v + and sensor +
    DC-: 12v - and sensor -
    IN: has the signal output wire of the sensor

    Jumper set to energize the relay when the sensor is triggered.

    Z probe is setup up as a endstop switch on E0 endstop input.

    Still using the old gcode settings.
    M558 P4 X0 Y0 Z1 H3 F200 T5000 R0 ; proximity probe via relay on E0

    G31 P500 X-36 Y8 Z0.8 ; (proximity) set threshold and offsets - z offset is last one - increase to get closer to the bed
    This is my default z offset. I use a macros to set it for the filament. PLA and PETG need a different offset due to the temperature difference. I put the appropriate G31 line in each.

    How often do you have to use baby stepping with the octocoupler.



  • @npm1 I've rarely used it. I use it to help fine tune my z offset in my macros for PLA or PETG


 

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