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Re: Looking for advice on multi 277vac to a 24vdc relay

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  • Dave Mucha
    ... voltage ... monitor ... where ... external ... which ... output ... drives ... to ... MID400, ... value ... logic O ... Pretty much the same as the
    Message 1 of 17 , Oct 3, 2004
      --- In Electronics_101@yahoogroups.com, "Chuck Waters"
      <weallbecrashin@y...> wrote:
      >
      > --- In Electronics_101@yahoogroups.com, "Chuck Waters"
      > <weallbecrashin@y...> wrote:
      > >
      > > catalog had diagrams, etc. -- there may even
      > > > have been "ac-input" ones in there, which would have two LEDs
      > back-
      > > to-back
      > > > in the device. Seems optimum for this application.
      > >
      > >
      > > Looks like it's time to go Shopping. :-)
      > > Thanks everyone for getting me unstuck.
      > >
      > > Chuck W.
      >
      > Look what I found. Looks perfect for what I need and maybe someone
      > else that wants to monitor AC devices.
      >
      > MID400
      > AC LINE MONITOR
      > LOGIC-OUT DEVICE
      >
      > DESCRIPTION
      >
      > The MID400 is an optically isolated AC line-to-logic interface
      > device. It is packaged in an 8-lead plastic DIP. The AC line
      voltage
      > is monitored by two back-to-back GaAs LED diodes in series with an
      > external resistor. A high gain detector circuit senses the LED
      > current and drives the output gate to a logic low condition.
      > The MID400 has been designed solely for the use as an AC line
      monitor
      > . It is recommended for use in any AC-to-DC control application
      where
      > excellent optical isolation, solid state reliability, TTL
      > compatibility, small size, low power, and low frequency operations
      > are required.
      >
      > FEATURES
      >
      > • Direct operation from any line voltage with the use of an
      external
      > resistor.
      > • Externally adjustable time delay
      > • Externally adjustable AC voltage sensing level
      > • High voltage isolation between input and output
      > • Compact plastic DIP package
      > • Logic level compatibility
      > • UL recognized (File #E90700)
      > • VDE recognized (file #102915),
      > – add option V (e.g., MID400V)
      >
      > APPLICATIONS
      >
      > • Monitoring of the AC/DC "line-down" condition
      > • "Closed-loop" interface between electromechanical elements such
      > as solenoids, relay contacts, small motors, and microprocessors
      > • Time delay isolation switch
      >
      > The input of the MID400 consists of two back-to-back LED diodes
      which
      > will accept and convert alternating currents into light
      > energy. An integrated photo diode-detector amplifier forms the
      output
      > network. Optical coupling between input and output provides
      > 2500 VRMS voltage isolation. A very high current transfer ratio
      > (defined as the ratio of the DC output current and the DC input
      > current)is achieved through the use of high gain amplifier. The
      > detector amplifier circuitry operates from a 5 V DC supply and
      drives
      > an open collector transistor output.
      >
      > The switching times are intentionally designed to be slow in order
      to
      > enable the MID400, when used as an AC line monitor, to respond only
      > to changes in input voltage exceeding many milliseconds. The short
      > period of time during zero-crossing which occurs once every half
      > cycle of the power line is completely ignored. To operate the
      MID400,
      > always add a resistor, R IN, in series with the input (as shown in
      > test circuit 1) to limit the current to the required value. The
      value
      > of the esistor can be determined by the following equation:
      >
      > RIN=VN-VF/IIN
      >
      > Where VIN(RMS) is the input voltage.
      > VF is the forward voltage drop across the LED.
      > IIN(RMS) is the desired input current required to sustain a
      logic "O"
      > on the output.


      Pretty much the same as the H11AA1 opto. add an external resistor
      and you're set.

      Dave
    • Chuck Waters
      ... Well if it is cheaper than the MID400 it might be worth switching too. The MID400 is almost $3. each. Mom and Dad spent a lot of time teaching me to shop
      Message 2 of 17 , Oct 3, 2004
        --- In Electronics_101@yahoogroups.com, "Dave Mucha"


        > Pretty much the same as the H11AA1 opto. add an external resistor
        > and you're set.
        >
        > Dave


        Well if it is cheaper than the MID400 it might be worth switching
        too. The MID400 is almost $3. each. Mom and Dad spent a lot of time
        teaching me to shop around for a better price. After all that brain
        washing I just can't sleep very well if I don't at least try.
        Thanks for the option Dave.

        Chuck
      • Dave Mucha
        ... resistor ... $ 3.00 ? Yikes ! for $4.00 I d buy the current transducer and not have to put together the pcb. The H11AA1 at digi-key is $0.48 each lots
        Message 3 of 17 , Oct 4, 2004
          --- In Electronics_101@yahoogroups.com, "Chuck Waters"
          <weallbecrashin@y...> wrote:
          >
          > --- In Electronics_101@yahoogroups.com, "Dave Mucha"
          >
          >
          > > Pretty much the same as the H11AA1 opto. add an external
          resistor
          > > and you're set.
          > >
          > > Dave
          >
          >
          > Well if it is cheaper than the MID400 it might be worth switching
          > too. The MID400 is almost $3. each. Mom and Dad spent a lot of time
          > teaching me to shop around for a better price. After all that brain
          > washing I just can't sleep very well if I don't at least try.
          > Thanks for the option Dave.
          >
          > Chuck


          $ 3.00 ? Yikes !

          for $4.00 I'd buy the current transducer and not have to put together
          the pcb.

          The H11AA1 at digi-key is $0.48 each lots of 10 or 65 cents each.

          and 39 cents at Jameco.


          Check www.findchips.com for suppliers.
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