[volt-nuts] HP 3458A cal

[Greg Burnett]

Hi Dick,

Agilent's online descriptions for 3458A calibration and services makes no mention of the Standards Lab calibration option. So no wonder so many customers order the wrong calibration. Yesterday in a phone conversation with their Call Center, I again gave my feedback that they should add a line item describing their Standards Lab Cal. They show that line item on their internal system, on their side of the firewall, but it doesn't show to external customers.

Yes, the STE9000 cal is automated. (STE9000 is an internal HP/Agilent test platform.) It supports the Fluke 5700, Fluke 5720 and Datron/Wavetek 4808. Because the published specs for these multi-calibrators are not tight enough to verify 3458A performance, the multi-calibrators are used only as short-term stable "power supplies". The way it works is that, just prior to testing the UUT, STE9000 derives calibration correction constants for the multi-calibrator (being used as a stable power supply) by measuring it against a 'golden' 3458A (which is re-calibrated in the Loveland Standards Lab every 90 days). STE9000 also corrects these derived constants according to the Standards Lab's supplied data for the particular 'golden' 3458A. Because correction constants are used, basically this process traces back to the Standards Lab's original MU + 90 day drift of the 'golden' 3458A + 15 minute drift of the multi-calibrator + noise, thermals, etc. STE9000 monitors internal temperatures of both the UUT and 'golden' 3458A - the test aborts if either device deviates more than +/- 1deg C for the duration of the tests. The combined uncertainty of this process at least makes it possible to calibrate a 3458A in the field, but remains significantly inferior to calibration of your 3458A directly in the Loveland Standards Lab.

The question has always been, "How do you calibrate a state-of-the art DMM, and how do you come up with the right equipment/process to do it?" The answer is not easy.

Best,
Greg



----- Original Message ----- 
From: "Dick Moore" <richiem at hughes.net>
To: <volt-nuts at febo.com>
Sent: Thursday, August 26, 2010 1:29 PM
Subject: Re: [volt-nuts] HP 3458A cal


@Greg Burnett -- thanks so much for that info -- I certainly did not know that, and the folks at Loveland never articulated that difference either. What a difference. I really appreciate your information. Now, to find the rest of the cash somewhere.....

I'm assuming the STE9000 cal is automated -- do you know whether they use a Fluke 5720 or 21?

Dick Moore