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Multiple AC inputs relay (light PLC)

Discussion in 'General Electronics Discussion' started by my_name, Aug 18, 2019.

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  1. my_name


    Aug 18, 2019
    I have a circuit like in attached diagram (multiple switches associated with light bulbs in different rooms). I'll like to add a new device (the green one with question marks) that has the following "specs":
    - 230V AC powered
    - 10 to 16 230V AC inputs (the same AC phase, but will be nice to have different phases too)
    - 1 to 3 relays (classic NO/NC) outputs
    - it should trigger based on how many input lines have active power (the number of active inputs to trigger should be adjustable from outside (jumpers, switches, etc)
    As a practical implementation example will be to trigger an actuator which closes a window if there are more than 3 lights turned on and to open the window if there are 3 or less light switched on.
    Most probable I need a PLC / PLR, but I hope there are other devices to do this in an easier way. So the question is: Are there such devices? If yes, what is their name?
    If I have to go with PLC, can you please recommend some to me? (So far I've seen that there are very few relays, PLCs or actuators running native with 230V AC inputs).
    - I'll like to keep the light part in existing form (so no Dali/KNX/similar switches)
    - It will be nice to be able to associate different "weights" to different inputs.
  2. BobK


    Jan 5, 2010
    I would use a microcontroller and use optocouplers to translate the inputs. You could use capacitors to limit the current to the input of the opto.

  3. Minder


    Apr 24, 2015
    This was also suggested in another forum posted to, using off the shelf Opto22's.
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