auto matrix controls
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  1. #1
    Join Date
    Apr 2005
    ulster county new york


    Well it's not new but I posted it in the wrong forum. I'm having a problem where I keep getting a communication failure on SBC2 stats. It happens almost once a week where all stats come up with a red flag and show 0.0 degree reading on my front end computer. Have to cycle control power to the controllers to get stats to reset. I was wondering if anyone else had this problem and know's what might be causing it, other than a power failure. VAV controllers are SBC-VAV1, and room sensors are STAT 2, the two button type with no digital display.

  2. #2
    Join Date
    Dec 2004
    San Francisco Bay Area
    It might be related to the Tech Tip Auto-Matrix posted last June. While it deals specifically with the STAT3, it might point you in the right direction:

    Subject: SBC-STAT3 displays the wrong value or no value at all when connected to an SBC- or NB-Series Controller.

    Description: When an SBC-STAT3 does not draw enough power, the SBC- or NB-Series controller may recognize it as an analog device, leading to incorrect temperature readings, the STAT resetting, or the display going completely blank.

    Solution: Depending on the specific problem observed, the solutions are as follows:

    Problem: STAT displays the correct temperature, but resets approximately every minute.
    Solution: Install a 10k resistor in parallel with the STAT3.

    Problem: STAT displays 137 or 138 and then resets.
    Solution: Install a 3.3k resistor in parallel with the STAT3.

    Problem: STAT display is blank, but a value of 137 or 138 can be read using SoloPro/Nb-Pro.
    Solution: Install a 1.5k resistor in parallel with the STAT3.

    Additional Tip: This problem is currently being addressed by Engineering and a firmware solution should be available in approximately 2 weeks.

    Not sure if your STAT's are digital or analog, but this might help you...

  3. #3
    Join Date
    Apr 2005
    ulster county new york
    Thanks it's something to go on.

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