This is not the sort of thing I don't usually do so I'll ask here:
What's the easiest and relatively cheap way of measuring high side DC current (0-30/50A, say 10% accuracy).
Preferably without using any drop resistors. I found hall sensors, any advice from users of these?
It has to be isolated (can't insert anything into ground loop) and the output would go to AVR so some processing can happen there, if needed.
M"TheM"
** Non contact, DC current sense with no resistive drop ?The ONLY way is to use a Hall effect transducer.
LEM Heme and Honeywell make nice ones.
I can vouch for them.
..... Phil
Ups, a typo, this is not the sort of thing "I usually do"
M
Allegro MicroSystems makes hall effect current sensors. But I can neither vouch for nor condemn them (they make other parts that seem to be OK, including hall effect proximity sensors).
-- Tim Wescott Wescott Design Services http://www.wescottdesign.com Do you need to implement control loops in software? "Applied Control Theory for Embedded Systems" gives you just what it says. See details at http://www.wescottdesign.com/actfes/actfes.html
Allegro Hall Effect sensors are pretty decent; I have used them. However they are intended for the currents minimum of 5A or so.
Vladimir Vassilevsky DSP and Mixed Signal Design Consultant
are intended for the currents minimum of 5A or so.
I'm looking at those, 712 looks decent. They are cheaper than some of the rail-to-rail high voltage opamps that are designed for this same task and those require the added drop resistor which is usually big.
The problem with the tiny allegro 712 is that they run 30A across 4 pins on a tiny so8 package, kind of scary. I wonder what happens if the load shorts, would the fast fuse break fast enough?
M"TheM"
** The data sheet says it withstands 100 amps for 100 mS- see " Overcurrent Transient Tolerance".
So, a fast acting 30 amp fuse should be OK.
BTW Farnell in the USA have stock.
...... Phil
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