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Reading Mil Std 1553B output

Discussion in 'Electronic Basics' started by [email protected], Apr 25, 2005.

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  1. Guest

    I have a marine navigation eqpt fitted with an output port (7 pins)
    which I know has Mil Std 1553B output. I need to tap this output for
    use on my computer. Is there any way of finding out what the data
    output is at the port? Is there any way of reading this data and using
    it with a computer?
  2. BobG

    BobG Guest

    Buy a 1553 interface card?
  3. fpd

    fpd Guest

    That's a start...

    MIL-STD-1553 is a balanced signal (has a + wire, a - wire and a
    ground/shield) for each channel. One channel usually has DUAL REDUNDANCY,
    meaning Channel 1A and channel 1B... if channel 1A fails (and the box is
    programmed correctly), channel 1B will be used (why? because it isn't nice
    flying home with half an airplane).

    The signal strength comes in two "volumes": DIRECT COUPLED and TRANSFORMER
    COUPLED. Direct is 3V to 9V p-p. Transformer is 9v - 27v p-p. When
    reading these signals, clip an O-scope Channel A onto 1553 Channel 1A+ and
    O-scope Channel B onto 1553 Channel 1A-. select ADD and INVERT on your

    MIL-STD-1553 is a 20-bit stream.

    Bits 0, 1, 2 are SYNC.
    Bits 3, 4, 5, 6, 7 are Remote Terminal
    Bit 8 is Transmit/Receive
    Bits 9, 10, 11, 12, 13 are Subaddress
    Bits 15,16,17, 18, 19 are Word Count/Mode Code
    Bit 20 is Parity

    The 1553 language is standard world-wide (yes, the same stuff from Bejing to
    Hoboken). How you get it to talk, or fill data buffers, or address Remote
    Terminals and Subaddresses with Mode Codes or Data is proprietary, so you
    will have to surf the site of the manufacturer.

    Have fun!
  4. fpd

    fpd Guest

    I forgot to mention... the bits are tranmitted at 1 megabits per second
  5. Guest

    Can I connect the port to the rx pin of the 9 pin serial port and make
    any sense? Are the 1553B interface cards standard or does it have to be
    custom made depending on the equipment
  6. neil

    neil Guest

    Excalibur make 1553 interface cards but they are about £1500 each.
    The data (as I recall, no doubt someone will correct/clarify...)
    is a serial differential transformer coupled stream, at 1Megbaud.
    Each data word is 16 bits, with a couple of start and stop bits.
    The words are grouped in messages, and sent under control of the bus
    You may have a controller or remote terminal (slave device).
    The voltage level ranges from 3 to 30 volts.
    Probably difficult to get a com port to talk/listen.
    hope this helps,
  7. fpd

    fpd Guest

    The MIL-STD-1553B "output" from the board can range from 3vdc to 27vdc. You
    do not want 27vdc on your computer's comm port.

    However, there is a TRANSCEIVER on the board somewhere. This transceiver
    has one side digital TTL levels (toward the circuitry) and one side analog
    (3vdc/9vdc or 9vdc/27vdc - toward the output).

    The transceiver IC usually has a brass tint to it, with twenty legs. The
    number on top will give you something to Google. Some of the TTL legs are
    TXA+, TXA-, TXB+, TXB-.

    Before clipping on to these TTL legs, please make sure your COMM port can
    handle the voltage levels... please?

    There might be another odd-looking connector, that would be the Discrete
    Output Signal port. It operates in RS-422 (balanced) and can be used as an
    input or output for synchronizing devices in the system.

    Just a little more info on 1553:
    - It is a command/response system.
    - The Bus Controller does all the commanding
    - The Remote Terminal(s) do all the responding.
    - Remote Terminals can range from 0 to 31 (five bits)
    - Each Remote Terminal can have up to 32 Subaddresses (five bits, 0 to 31)
    - The bus architechture is like that of the old-school thicknet ethernet.
    - A 1553 device will have a "stub" that connects the device to a "T" or
    "Transformer Coupler"
    - The "T" or "Transformer Coupler" connect the stub to the bus (backbone).
    - Each end of the bus is terminated, to reduce reflected waves below the
    1553 threashold.

    Guess that's all for now. Time for dinner.
  8. fpd

    fpd Guest

    Neil C.? GE32?
  9. neil

    neil Guest

    I'm Neil from Chatham in Kent, England.
    Work (currently) for BAE Systems.
    Not sure what the GE32 is, so it's probably not me you're thinking of.
  10. fpd

    fpd Guest

    BAE - GoldExpress, perhaps.
  11. fpd

    fpd Guest

    Try this 1553 introduction:
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