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Cambridge Avionics has a device called CAV13 (http://www.cambridgeoperations.com/CAV13_Manual_3_0.pdf) that reports ECU status information from the CANbus, and one error is called the "interlane keepalive discrete signal failure", and it is only present on 915iS engines, distinct from the "interlane communication failure" present on both. I assume this status is triggered if an interlane watchdog times out. I know what interlane communication is and I know what a keepalive is, and I can guess why it's necessary to use discrete keepalives (to distinguish between a lack of interlane status information and lack of a functional interlane) but why do only 915iS engines report this status and not 912iS? Do 912iS engines not have an interlane keepalive or do they report interlane keepalive time out as an interlane comm failure or do they just not report if the connection times out (I suppose that's what it means by failure)?

Do I perhaps have to take an iRMT course like "9 Series Injected Diagnostic Course" to find out the answer?

  • Re: What is the "Interlane keepalive discrete signal failure" ECU status?

    by » 3 weeks ago


    First time I have seen this thread, odd that there is no reply.  I will forward to a colleague to see if they have an answer.

     

    Cheers


  • Re: What is the "Interlane keepalive discrete signal failure" ECU status?

    by » 3 weeks ago


    Hi again...ok this one took a bit of digging.  Indeed the logic in the board is different on the 915 iS from the 912 iS.  Basically there is the turbo monitoring sensors and in addition the knock sensor is active in the 915 and not yet on the 912.  It is a rather odd call out because it is for deep diagnostics to be sure that when turning the internal switches on and off it is to monitor each lane has enough information.  Typically there is always communication errors, such as when you switch off a lane for test or in initial start up before the Generators are both online and synchronized.  Just because it is in the data stream I have no idea why it would be displayed on an instrument.  it is more of a log file report item to help in deep diagnostics.  The term and the report is special to the type 915 engine.  

    The type 915 then has a different board as they monitor more stuff.  When redoing this for the 915 this was added in the system.  Given the sample rate is so high we always will see short system "failures" that are completely normal in the operation of a dual system.

     

    Cheers


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