[volt-nuts] HP3457 quirks and gripes

[Mark Sims]

My main gripe with the 3457A is that high-res mode.  It was just plain stupid on HP's part to not make the meter operate directly in 7.5 digit mode.  Why does one have to read a separate register and manually add it to the reading?  Come now... can't a microprocessor do that better than a person.  In fact I built a 3457A GPIB interface to a MegaDonkey touch screen LCD controller specifically to read the high res register and do the addition/display.

Another thing to watch out for on the 3457A is the "seams" between the ranges.  Even on units freshly checked out and calibrated from HP I have seen rather large errors in readings when I put a precision resistance decade box or voltage cal source on the thing.  Stepping the value from say 2.9V to 3V  and from 3.1V to 3V produces different readings that were out of spec. (the 3V point seems the most error prone).

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