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  1. #1
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    Help! GPL to Tridium conversion issues

    I'm running into a couple issues with a GPL conversion. I'm hoping someone else has seen these as well, and has found a solution.

    First, the Ramp block. In GPL, Ramp can be sued to slow down the rate of change of a value, only allowing X change per Y seconds. In Tridium, Ramp is a vastly different animal, creating something like a sawtooth wave. Does anyone have a way of reproducing a GPL type Ramp function in tridium?

    Second, GPL has a Force Reliability block, that will force the logic to use the existing value, even if it's in fault. In tridium, if a point goes into {fault,down,stale} statuses, the subsequent blocks not only don't use that value, the calculation blocks respond with 'nan' (not a number), which does not calculate well, and throws off the entire plant. I need something that will force Tridium to continue to use the value even with the {fault} condition. Basically strip the status off, and just use the last known value.

    Anyone run into these before? I feel like there should be a simple solution to these that I'm just overlooking, but for the life of me, I can't figure them out.

    Duncan

  2. #2
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    Kit control object status demux would solve your nan issue. The ramp function is doing what?? Might be another way to do it?? You can use the the numeric delay block possibly.

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  4. #3
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    Numeric delay is exactly what I was looking for. I thought it was like a boolean delay, and never thought further.

    The status demux will give me a T/F boolean output if any of the various statuses exist. But all the outputs are Boolean. What I am looking for is a way to take a Numeric point that shows [874 gpm {fault}], and turn it into [874 gpm {ok}]. I need to strip off the status condition, because I can't perform calculations while it's on there.

  5. #4
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    Yes use the boolean output of the demux to a numeric switch. In status to switch goes true pass the 874 hard coded value. In switch goes false pass null.

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  7. #5
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    Sorry for not being clear - I'm not looking for a hard coded 874 - that was a random number I came up with to use as an example. I need to use the last known good value. So if it was 70, I need to use 70 - if it was 2300, I need to use 2300. Whatever the value was at the time of the failure.

    I can create a fail-to value easily, simply by writing to in16 on a Numeric writable, and having my fail-to value in the fallback.

  8. #6
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    Numeric latch on demux change of state?? Latching current value release when demux back to normal

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  10. #7
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    Not fast enough. By the time it trips the latch, the latched value has the fault.

    I did just figure out a way, however. I ran the Numeric point into a conversion block, statusNumericToDouble, then back into a DoubleToStatusNumeric. It comes out the far end with exactly the same number, without the status.

    Thanks for taking the time to help me out. You solved one of my issues, and helped me talk out the other.

    Duncan

  11. #8
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    Glad you got it!!

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