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exodia505
Joined: 07 Feb 2012 Posts: 34
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Current measurement |
Posted: Sun Mar 04, 2012 9:44 am |
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Hello!
what's the best way to measure current with pic ? _________________ NOway!! |
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asmboy
Joined: 20 Nov 2007 Posts: 2128 Location: albany ny
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Posted: Sun Mar 04, 2012 10:07 am |
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it all depends on:
1- AC?
2-DC?
3-the RANGE ?( 1 ua is very different from 100A )
4- and if AC - the FREQUENCY range |
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exodia505
Joined: 07 Feb 2012 Posts: 34
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Posted: Sun Mar 04, 2012 10:10 am |
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i meant DC current (0-5A) _________________ NOway!! |
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asmboy
Joined: 20 Nov 2007 Posts: 2128 Location: albany ny
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Posted: Sun Mar 04, 2012 10:27 am |
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Hi side or low side sensing -or floating?
Whats the CIRCUIT you intend to use this with ??
Even with an optimum circuit,
keep in mind that with a 10 bit A/d pic
you can only resolve to 7.8 ma increments and 1.95 ma with a 12 bit PIC.
The circuit you will need depends on the answer you give to the first line of this message.
BTW: for real product - or school project?? |
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gpsmikey
Joined: 16 Nov 2010 Posts: 588 Location: Kirkland, WA
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Posted: Sun Mar 04, 2012 10:35 am |
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Contact or non-contact (can you insert a sense resistor in-line with the load or do you have to not modify the wiring) ? What kind of frequency response do you need ? (there is DC then there is "fluctuating DC" where you are monitoring a load for example). What kind of voltage drop can you tolerate across the sensor ? To "measure current" you first have to define the requirements of what sort of "intrusion" into the circuit you want to measure can be tolerated.
mikey _________________ mikey
-- you can't have too many gadgets or too much disk space !
old engineering saying: 1+1 = 3 for sufficiently large values of 1 or small values of 3 |
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SherpaDoug
Joined: 07 Sep 2003 Posts: 1640 Location: Cape Cod Mass USA
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Mike Walne
Joined: 19 Feb 2004 Posts: 1785 Location: Boston Spa UK
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Where are you sensing? |
Posted: Tue Mar 06, 2012 3:37 am |
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Is your current unipolar?
You said 0-5A, but could the current change direction? (i.e. -5A - 0 - +5A)
Where abouts in your circuit are you wanting to measure? (0V lead, above VDD, below VSS, floating)
Do you need a Hall effect probe?
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And on and on .........
Mike |
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