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Help please 4-20mA display

Discussion in 'General Electronics Discussion' started by BlueFox21, Jun 6, 2013.

  1. BlueFox21

    BlueFox21

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    0
    Jun 6, 2013
    Hello,

    This is my first post so please be gentle with me!! I'm an electrical, instrumentation and plc engineer. I'm building a 4-20mA signal generator, I have all the circuit for the generator itself all sorted however I would like to have a display on it as well to show the current reading, ideally three 7 segment displays to show for example 14.7 (mA). Is there a chip or anything I can buy which will produce either a BCD signal or a mA to voltage conveter (which I can then convert to BCD)? I'm looking for cost effective as well so a simple chip would be ideal rather than a PIC as although the chip isn't too expensive I will need a programming board to program it I believe which is extra expense. Any help would be greatfully received as said above I'm not an electronics expert although have done quite a bit of electronics in the past but that was over 10 years ago now! I am also going to add a 0-30v and 0-10v analogue signal to this as well and a reading for a resistance based temperature sensor shortly as well once I have got the 4-20mA part all up and running.
     
  2. Harald Kapp

    Harald Kapp Moderator Moderator

    9,411
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    Nov 17, 2011
    Use a simple panel meter (here is but one example). A panel meter usually measures voltage, so you will need to add a current sense resistor into the output wire of your 4-20mA source and measure the voltage drop across this resistor.
     
  3. BlueFox21

    BlueFox21

    2
    0
    Jun 6, 2013
    Thanks for the reply. That looks ideal. Anyone know where I can source that kit in the uk or will I have to buy individual components? Thanks again
     
  4. Harald Kapp

    Harald Kapp Moderator Moderator

    9,411
    1,922
    Nov 17, 2011
    E.g. here or google "panel meter uk.
     
  5. woodchips

    woodchips

    43
    0
    Feb 8, 2013
    Cheap DVM?
     
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