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.

    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


  • administrators

    You can find wiring recommendations for various types of sensor at https://duet3d.dozuki.com/Wiki/Connecting_a_Z_probe.

    Older BLTouch models needed the 240 ohm resistor added to reduce the output to 3.3V. Newer ones have a trace to cut instead.



  • @dc42 said in Octocoupler and LJ12A3-4-Z/BX:

    You can find wiring recommendations for various types of sensor at https://duet3d.dozuki.com/Wiki/Connecting_a_Z_probe.

    Older BLTouch models needed the 240 ohm resistor added to reduce the output to 3.3V. Newer ones have a trace to cut instead.

    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


  • administrators

    Any time you make changes to a Z probe, test it before using it to home or do bed probing. See https://duet3d.dozuki.com/Wiki/Test_and_calibrate_the_Z_probe.


 

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