Setting in Tool kit of 5504GI

Discussion in 'C-Bus Toolkit and C-Gate Software' started by KCW, Mar 18, 2008.

  1. KCW

    KCW

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    I have a PT1000 temperature sensor connect to channel 1 of 5504GI. The specification of the sensor is 0 degree celsius equal to 1000 ohm and 3.85 ohm/K. The operating range is 0 to 50 degree celsius. What data can I input in Channel 1 tab?
    Input Type?
    Prefix?
    Multiplier?
    Offset?

    Can the actual temperature be shown in PICED by using SystemI/O or other method?
     
    KCW, Mar 18, 2008
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  2. KCW

    MIB

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    Hi KCW,

    I'm not familiar with temperature sensor theory and application, but based on your post and some quick Googling, I think I understand what you're asking. If I'm wrong, please forgive me. :)

    Basically the C-Bus General Input Unit, (PC_GIM), can translate the values coming from your PT1000, into a level to broadcast out onto C-Bus. These levels take a value between 0 and 255. Thus, you want to translate the value coming into your PC_GIM's channel into a value within the range of 0 to 255.

    If I understand it correctly, you're saying that when the PT1000 measures a temperature of 0?C, the resistance value will be 1000Ω, and for every 1?C increase in temperature, the resistance will increase by 3.85Ω. So for 0?C, 1?C, 2?C, etc. you will get 1000Ω, 1003.85Ω, 1007.7Ω, etc. This means that the resistance for the maximum temperature you want to consider, (being 50?C), is 1192.5Ω.

    Therefore you want to translate values in the range [1000Ω, 1192.5Ω] into a C-Bus level into the range of [0, 255] and vice versa.

    Hence, you will get:
    Offset = 1000
    Multiplier = (1192.5Ω - 1000Ω) / (255 - 0) = 0.7549

    As for the input type, I can't remember what's in the list, but try any of the resistance ones and see what happens. I can't remember if the multiplier and offset values override this selection or not...

    The prefix, if I recall correctly, is for broadcasting via the measurement application. Again, I don't recall what's in the list at this time, (I don't have Toolkit here). You can get values into PICED via the "broadcasting" functionality, but I've never used it personally. Hopefully someone else can help you here.

    I may be wrong with some of what I've said here, so hopefully someone on here can clarify.
     
    MIB, Apr 1, 2008
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  3. KCW

    KCW

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    Thank you very much. I will test with these setting. Thank you again.
     
    KCW, Apr 6, 2008
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  4. KCW

    7iron

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    What I found was

    on the 0 to 3000 ohm range

    0 reading on the 50004GI = 0 ohm
    255 reading on the 50004GI = 3000 ohm

    Therefore:

    0 degrees C = 1000 ohm on the PT1000 = 1000/3000 * 255 = 86 reading on the 50004GI

    50 degrees C = 1194 ohm on the PT1000 = 1194/3000 * 255 = 101 reading on the 50004GI

    With Scaling Multiplier of 3.03215 and Offset -257.732

    You get for:

    0 deg C = 1000 Ohm

    1000/3000 * 255 * 3.03215 -257.732 = 0

    For:

    50 deg C = 1194 Ohm

    1194/3000 * 255 * 3.03215 -257.732 = 50


    Untitled.png
     
    7iron, Oct 6, 2013
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