Agilent Technologies is phasing out the popular 34401A multimeters. Will the 34461A be a worthy successor?
On June 17, Agilent Technologies announced a replacement for its longtime workhorse multimeter, the 34401A -- the 34461A.
Introduced in 1992, before HP split off Agilent, the HP 34401A and then the Agilent 34401A can be found on many an engineer's bench and in many an automated test system. Many, if not most, of those HP models are still in use today.
The 34461A ($1,095) is designed to replace the 34401A. In fact, you can even find a comparison page that you can use to compare the two meters.
Agilent's 34461A digital multimeter is billed as the replacement for the 34401A.
Comparing the 34401A and 34461A, you'll see that many specs are equal to those of the 34401A or better in the 34461A. Agilent also highlights the fact that the 344601A is, "a 100 percent drop-in replacement for the 34401A," but if you use your 34401A in a test system and communicate over RS-232, you'll need an RS-232/LAN or RS-232/USB converter. The RS-232 port is gone, as is a GPIB port, but GPIB is an option on the new meter. Should Agilent offer an RS-232 option or will you use a converter?
"What? You mean my workhorse multimeter is being discontinued?" That's what I thought when I read the press release, so I asked product manager Tami Pippert. Here's what she had to say:
We are not announcing 34401A discontinuance at this time, but we do plan to do so in the future -- no date has been set at this time. When we do announce 34401A discontinuance, we will provide advance notice to allow our customers time to make final purchases. We are broadly communicating the 34461A as the 34401A replacement for those customers who want to start evaluation processes as early as possible.
An early 34401A with the HP logo, before the 1999 Agilent spinoff.
Many HP 34401A meters are still in use today.
Agilent's 34461A data sheet shows a color graphical display that lets you plot measurements, and display things like min and max. There's also temperature measurement available through a thermistor or RTD. Many engineers have developed their own PC software to convert resistance measurements from the 34401A into temperature units.
Agilent claims that the 34461A has measurement specifications that are equal to or better than those of the 34401A. But people who calibrate test equipment know that instruments with a calibration history add confidence because they know how the instrument should perform between calibrations. Given the long history of the 34401A, Agilent's engineers surely performed extensive testing on the 34461A. But is there any substitute for calibration history? I'll let you decide. Still, I had to ask Pippert about how Agilent handled the history situation. Here is her reply:
The 34401A is legendary for its reliability, both electrically and mechanically. In developing the new meters, the testing by the design team was extensive -- shock, vibration, extreme environmental conditions, and long-term testing of component reliability. Given that we closely track performance of our products and have all the info on when there are any problems, field service history, repairs, etc., having a reference product like the 34401A with 20+ years in the field is to our advantage in developing the 34461A.
We have the history of all the various components, circuits, and sub-systems, and where possible, we leveraged that design forward. That is one of the true benefits of having many of the same folks on both the original 34401A team as the Truevolt team -- to have that design history and knowledge front and center in everything they do.
The 34461A data sheet provides measurement uncertainty data for periods up to two years. Has Agilent been testing the meters for two years to prove that specification, or is there a statistical method for extrapolating that data? I'd like to hear from Agilent on how the two-year data was achieved.
Do you have a 34401A? Will you order several more when Agilent issues a call for last orders? Will you evaluate a 33461A? If so, what tests will you perform before deciding what to do?