Galaxy: How do I perform a loopback test on the signal converter in a RS-422 Communication Setup?

Potential Symptoms

How to do a loopback test on RS232 to RS422 signal converter?

Environment

  • Product: Galaxy, AF-3010, AF-3020, AF-3050, AF-3060, AF-3080, AF-3090, AF-3150, AF-3160, AF-3165, AF-3180, AF-3190, AF-3197, AF-3200, AF-3400, Electronic Message Center (EMC) or Board (EMB), Marquee, Readerboard, Display
  • Component: RS-422 Communication System, RS/232 to RS/422 Signal Converter (Daktronics Part Numbers: 0A-1127-0255 or 0A-1127-0237)
  • Control System: Venus 1500

Resolution

Utilize one of the following Software/Utility methods to preform the loopback test: Step 1: Setup the Loopback Test on Serial cable at computer. This setup may or may not be using a USB to serial adapter. 
  1. Perform steps in: How to perform a loopback test on a RS232 system
  2. If test pass be sure to test for fail. Remove the loopback jumper and run the test. It should fail. If the test still passes there is an issue with the test and should be preformed again.
  3. If test passes - a loopback test would need to be run on the serial output of the computer or may require the serial adapter be replaced. Depending on which one is found follow one of the articles below:
    1. Follow: Galaxy, No serial communication, Prolific or Moxa adapter/port locked up, DD2112087.
    2. Follow: No communication between computer and signal converter, Failed serial port, DD2006911.
  4. If test passes move onto Step 2.
Step 2: Setup the Loopback Test on the Phoenix Terminal Blocks.
  1. This test can be performed on J4 or J5 (only one jack at a time).  Wires going to the display should be removed at this time and set aside.  Use the spare green plug in the signal converter if available.
    • Note: Write down which wire colors were connected to each pin.
  2. Using a conductor (paper clip or copper wire) jump pins 2 (RX-P) to 4 (TX-P) and then jump pins 3 (RX-N) and 5 (TX-N).  See the diagram below for details.
    Signal converter loopback.png
    1. If test passes move onto Step 3.
    2. If test fails follow: Serial Communication, unable to connect, failed signal converter.
Step 3: Setup the Loopback test on the field run (cable running from the building to the surge card)
  1. This test can be preformed at the communication box located at the display. Similar to Step 2 we will be twisting wires on the cable that connects to TB1 of the surge card together.
  2. Twist Wires on pins 2 and 4 together and pins 3 and 5 together. Be sure to note wire color for re-termination to connector.
    1. If test passes be sure to test for fail.
    2. If test passes preform move onto Step 4.
    3. If test fails the cable run will need to be replaced or it may be possible to upgrade to a wireless communication method. Call Daktronics Technical Support 1-888-325-8766.
Step 4: Setup the Loopback Test on the Phoenix Terminal Blocks at TB2 of Surge Card.
  1. Similar to the steps outlined in Step 2. above, place loopback jumpers on 2 and 4 and pins 3 and 5.
    Loopback locations
    1. If test passes test for fail. 
    2. If test loopback test fails follow: Galaxy, No communications, Failed RS-422 surge card .

Additional Information

KB ID: DD2003344


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