LM3813 to mesure +-7 Amps courant
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Posts: 46,084
Dear all
I try to use a LM3813 to mesure +-7 Amps courant.This component have
a PWM output.
I use the pulsin instruction from the Basic Stamp 2 to get the pulse
width.
The maximum sample time is 50 ms for one shot
The Courant value for 0 Amp is 50% (25 ms)
The courant value for+7A is 95.5%(47.5ms)
The courant value for-7A is .5%(2.5ms)
In fact 0 amps value read by BS2 is 25 600 micro second (+600micro S)
With a lamp connected the value is 26 068 (0.5 amps)real value
checked with a voltmeter is 1.64 Amp so there is something wrong!
So is there some timing restriction using pulsin instruction in the
BS2?
Have you met a simillar application in the past ?
I will try to download lm3813 data sheet in the file directory
THANKING YOU IN ANTICIPATION
Best regards from France
I try to use a LM3813 to mesure +-7 Amps courant.This component have
a PWM output.
I use the pulsin instruction from the Basic Stamp 2 to get the pulse
width.
The maximum sample time is 50 ms for one shot
The Courant value for 0 Amp is 50% (25 ms)
The courant value for+7A is 95.5%(47.5ms)
The courant value for-7A is .5%(2.5ms)
In fact 0 amps value read by BS2 is 25 600 micro second (+600micro S)
With a lamp connected the value is 26 068 (0.5 amps)real value
checked with a voltmeter is 1.64 Amp so there is something wrong!
So is there some timing restriction using pulsin instruction in the
BS2?
Have you met a simillar application in the past ?
I will try to download lm3813 data sheet in the file directory
THANKING YOU IN ANTICIPATION
Best regards from France
Comments
> Dear all
After one night idea are more consistent .
In fact it was a hardware problem the insertion resistor(0.004 ohms )
to measure courant is so little that you can read the wire
resistance when it 's bad connected (and you think that hardware is
ok!!) .Now it works properly
> > Best regards from France