[volt-nuts] Quality Multimeters: HP 3457A

[Ulrich Bangert]

Gentlemen,

> I have in mind, that the 3457A may also be used in 7 1/2 
> digit mode, but 
> could not find this in the manual.

The 3457A has an additional "high resolution register" that may be read
completely apart the normal measured result over GPIB and added to the
measured result for appr. 7 1/2 digit resolution. I have used this feature
with a PT100 4-wire measurement to give me a 1/100 degree C resolution for a
thermometer. 

BTW: The 3457A is one of the devices that does not make use of the GPIB
EOI-line (unless explicitely told so). Unless you are aware of that getting
GPIB communication to work can be a real pain.

Best regards
Ulrich Bangert

> -----Ursprüngliche Nachricht-----
> Von: volt-nuts-bounces at febo.com 
> [mailto:volt-nuts-bounces at febo.com] Im Auftrag von Dr. Frank Stellmach
> Gesendet: Sonntag, 2. August 2009 21:51
> An: volt-nuts at febo.com
> Betreff: [volt-nuts] Quality Multimeters: HP 3457A
> 
> 
> Hello Roy,
> 
> take into account the 34401A also, as the spec (stability) are very 
> similar to the 3457A.
> The 3457A has some extended DCI ranges, compared to the 
> 34401, but also 
> no complete ACAL feature, as the 3458A.
> 
> I have in mind, that the 3457A may also be used in 7 1/2 
> digit mode, but 
> could not find this in the manual.
> The 34401A can deliver more digits than 6 1/2 via GPIB 
> Linearity is 2ppm, but the 3457A is not specified at all in 
> this regard.
> 
> Seems to me, that the 3457A is an elderly design, discretely 
> built, and 
> has not been so common.
> 
> The 34401A design is derived from the 3458A, more compact and 
> ruggedized.
> 
> 
> Anyhow, better go for the 3458A.
> ACAL, its stability and precision, the complete set of 
> current ranges, 
> the different possibilities to make high precision AC 
> measurements, and 
> the digitizing fetures are all worth the money.
> 
> I was lucky to pick a 9 year old unit here in Germany for about 3000€ 
> recently.
> 
> I built a LTZ1000A based, dual reference, as a replacement of 
> Fluke 732A 
> / 732B or  7001.
> Short term stability (1h) compared with the 3458A is around 2e-7.
> 
> Then I added a one decade precision divider for linearity 
> testing (like 
> a 720A), and a 10:1, 100:1 reference divider, like the 752A.
> 
> Mentioned commercial devices are also rare here, but if you 
> find them, 
> they are too expensive in most cases here in EU. I think, the 
> US market 
> would be a better place to acquire them, despite tax & toll.
> 
> 
> The analogous device to the time-nuts cesium clock would be a 
> Josephson 
> array plus HF-devices plus liquid helium. It's a pity that 
> "volt" cannot 
> be transferred wireless also..
> 
> Frank Stellmach
> 
> _______________________________________________
> volt-nuts mailing list -- volt-nuts at febo.com
> To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
> and follow the instructions there.