Need help with lookup table or direct calculation

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  1. - 6th October 2006, 18:01 #1
    Acetronics2's Avatar
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    Wink other solution ...

    Big Tables ???

    No pwôblem, missiou !!! Use an excel sheet creating a text file ( Retlw xx ...) and some asm ( RETLW ...) lines.

    Here are ( simple !!! ) examples

    Alain
    Attached Files Attached Files
    ************************************************** ***********************
    Why insist on using 32 Bits when you're not even able to deal with the first 8 ones ??? ehhhhhh ...
    ************************************************** ***********************
    IF there is the word "Problem" in your question ...
    certainly the answer is " RTFM " or " RTFDataSheet " !!!
    *****************************************
  2. - 6th October 2006, 19:09 #2
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    Since the RETLW method stores 1 byte per instruction which takes 2 bytes.
    A table of 1024 words would use 4096 bytes, instead of the 2048 bytes used by the method shown here ...

    Using EXT with Labels
    http://www.picbasic.co.uk/forum/show...php?t=3891#LAB

    If you are using a 16F as the .zip example shows, then RETLW would be better because it can only store 14-bit words, but not for an 18F.
    <br>
    DT
  3. - 7th October 2006, 10:18 #3
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    Talking a thought for the programmer

    Hi,Darrel

    I think we also must consider the table loading work ... ( humour !!! )


    Alain
    ************************************************** ***********************
    Why insist on using 32 Bits when you're not even able to deal with the first 8 ones ??? ehhhhhh ...
    ************************************************** ***********************
    IF there is the word "Problem" in your question ...
    certainly the answer is " RTFM " or " RTFDataSheet " !!!
    *****************************************
  4. - 10th October 2006, 17:55 #4
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    Hey Darrel,

    That table approach works well. now im trying to implement a PID controller to maintain the temperature at a desired temp by switching heaters on/off. I am thinking of using the PWM to do this. But I have to calculate my gain,I and D first. I think this can be done using the step response, but do you know what approximate values i can start out with and how to control the PWM with the output drive?
  5. - 10th October 2006, 19:37 #5
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    Hey Darrel,

    That table approach works well. now im trying to implement a PID controller to maintain the temperature at a desired temp by switching heaters on/off. I am thinking of using the PWM to do this. But I have to calculate my gain,I and D first. I think this can be done using the step response, but do you know what approximate values i can start out with and how to control the PWM with the output drive?
  6. - 11th October 2006, 09:01 #6
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    Wink Already cooked !!!

    Hi, Nverma

    Have a look to : http://www.parallax.com/dl/docs/prod...eb-PC-v1.0.pdf

    there's a PID heather project with ALL the coeff. adjustment procedure ...

    AND PBP Basic compatible written overall ...

    Alain

    PS ... page 245 ...
    Last edited by Acetronics2; - 11th October 2006 at 09:07.
    ************************************************** ***********************
    Why insist on using 32 Bits when you're not even able to deal with the first 8 ones ??? ehhhhhh ...
    ************************************************** ***********************
    IF there is the word "Problem" in your question ...
    certainly the answer is " RTFM " or " RTFDataSheet " !!!
    *****************************************
  7. - 11th October 2006, 19:27 #7
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    Thanks Alain,

    I have that same document and have been reading through it. Its quite helpful. I will continue working on this and let u know if I have any further questions.

    Nikhil
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