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Retro-fitting elevator display

Discussion in 'General Electronics Discussion' started by Jacques Nel, Nov 16, 2016.

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  1. Jacques Nel

    Jacques Nel

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    Nov 16, 2016
    Howzit Guys.

    I am a Heavy Current Electrical Engineer but I've always been a fan of electronics and what they can do.

    I recently started playing with display units (salvaged from elevators).
    I then set up a basic 24V circuit where I can basically switch 3 switches on and off, sending 24V to wherever my heart desires:).

    Now this sounds very basic at the moment but my plan is to use this ability of switching voltage on and off to operate a elevator display. For testing purposes the basic elevator display (FLOOR 1, FLOOR 2, ect) will be used.

    My problem is finding a device that can take the signal/signals (planning on 3 X +24V inputs and a common) to convert these inputs into a signal that the display can understand (Think the display uses CANbus usually).
    Is there a device available that I can use to manipulate my 24Vdc into sending signals to my display?

    Any help would be greatly appreciated.

    Thanking you in advance
     
  2. Wakoli Chokeli

    Wakoli Chokeli

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    Nov 16, 2016
    If the signal entails/contains deferent custom signal e.g digital, then you can use a micro-controller with unlimited possibilities. Otherwise depending on the nature of the display you can directly regulate the voltage and send it. The following states/messages can be sent: 000,111,100,110,101,010,011,001,011 even without a micro-controller, and then you choose what to do using the display unit e.g assigning Floor numbers and Lift direction. Since am not informed of the nature of the display unit, I cant directly advice a ready made device from the market. Nevertheless you can send me more details about the whole system and will get you a definitive answer.
     
  3. Jacques Nel

    Jacques Nel

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    Nov 16, 2016
    I have attached a google image of the display unit I have. Still need to do some research on how the actual unit works and what signal it needs to receive. I have no documentation on this unit so its a bit of a shot in the dark for me. I know very little on the subject but love fiddling :)

    As far as the signal/converter I need. I am basically planning and taking 24V from a rectifier and using a switch (basic N/O contact) to switch the voltage ON/OFF, hoping that there is a unit or microprocessor available that can send out a signal when it sees the 24V go ON in the input.
     

    Attached Files:

  4. Bluejets

    Bluejets

    4,277
    909
    Oct 5, 2014
    Microcontrollers do not handle 24v. You will have to use resistor dividers to ensure the voltage never exceeds the 5 v or 3.3v or whatever each micro is rated for.
     
  5. Jacques Nel

    Jacques Nel

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    Nov 16, 2016
    I was thinking of buying a Arduino and coding it myself. Adding that I have never coded anything before, but this is probably the best time to learn?
     
  6. Wakoli Chokeli

    Wakoli Chokeli

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    Nov 16, 2016
    True Mr. Jets...another option is totally isolating the voltage, or even using a current/voltage/magnetic sensor. This of course depends on what else the 24V lines are doing. I think they will be powering the lift hence you may get fluctuations in current which may not be great for the signal lines here. Its never late for coding and coffee, and Arduino is a great place to start.

    According to the images: Check for the datasheet of SM. 04VL16/A. I bet finding the datasheet will be hard, but you can contact the manufacturer if google-ing fails. Go through the datasheet and you will be in a position to know what signal to sent since it has on-board controller. With "CAN Bus serial communication" I think it should be a straight forward task with Arduino.
     
  7. Jacques Nel

    Jacques Nel

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    Nov 16, 2016
    Thanks for the reply guys.

    I have had no luck tho. Datasheets are non existing. I have ordered myself a arduino to try my hand at coding so hopefully I have more luck there although I have no idea how I am going to connect the display up.
     
  8. Jacques Nel

    Jacques Nel

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    Nov 16, 2016
    I found some information on the Display Unit. The connections I am interested for comms is the CANH and CANL.

    I have attached the Datasheet I found to this reply.

    Now the only problem I have is sending the correct signals to the display unit when triggered to do so. My plan is to use Arduino so that when a certain input is triggered the set signal has to be sent through the CANbus shield to the display. This sounds easy but seeing as I have zero coding experience I guess this will be like learning to walk again.. Very confused.

    Any advice Guys
     

    Attached Files:

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