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Thread: Graphing the Change in Temperature

  1. #1
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    Graphing the Change in Temperature

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Ive had a go at overlaying a graph of the change in temperature onto the normal temperature graph. The attached graph is for a "kinda dodgy" roast of Peru Ceja de Selva that Stuart and I did a couple of nights ago. I say dodgy because we had the temperature turned up too high at the start. This meant that we reached first crack at 10:50 without adjusting the heatgun temperature at all until just before first crack.

    So the Orange line is the normal temperature curve, and the blue is the change in temperature. I calculated this by comparing the current temperature to what the temperature was 10 seconds ago. Because the temperature is only recorded in 1/10ths of a degree, this causes a very wonky graph, so the blue line is the average change in temperature over 30 seconds.

    The higher the blue line is, the faster the temperature is rising. Where it dips below the base line (0 degrees/min) is actually when our temperature started going down.

    I was impressed by how smooth the orange curve was. The straight line between 12:20 and 14:30 was when the coffee snobs software crashed and stopped recording... (This actually happens quite often -- anybody else experienced this?).

    So, any thoughts?


  2. #2
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    Re: Graphing the Change in Temperature

    Never had the software crash at all, what version are you using?
    USB or Serial.
    With the USB running under vista i found the software would flicker all the time like it was trying to refresh but USB under Win2K it works flawlessly.

    Mal

  3. #3
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    Re: Graphing the Change in Temperature

    Never had the software crash at all, what version are you using?
    USB or Serial.
    USB & WinXP...

    Its been cutting out about ever 2nd roast or so. Unplugging the usb cable and plugging it in again seems to fix it. It did it towards the end of the second roast when we did you roasts consecutively? Could the multimeter be trying to save power and be turning off USB output? My old thermometer used to turn off after about 30 mins which would always been about halfway through a second roast :-P

  4. #4
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    Re: Graphing the Change in Temperature

    Fair comment, it could be but i havent really looked at the specs of the newer USB DMM to see if it has that function or not. I know the old serial DMM would stay on regardless of how long it was connected to the roast monitor software.

    Could it be a USB port issue? Have you tried a different USB port.
    I hate USB, while convenient, they are a bugger to troubleshoot when things go wrong.

  5. #5
    CoffeeSnobs Owner Andy's Avatar
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    Re: Graphing the Change in Temperature

    Behmor Coffee Roaster
    Quote Originally Posted by 28150D1008120519600 link=1242868478/2#2 date=1242916174
    Could the multimeter be trying to save power and be turning off USB output?
    You are close... its more likely that the PC is turning power off!
    Check your enviro power save settings in the bios and in windows.

    I think that will fix it.



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