I'm sure that many of you have an Agilent or even HP 34401A in your home or work lab. What will you do if you need a replacement? Will you upgrade to the newer model 34461A or look for a 34401A on the used market?
I have a 34461A, as well as a 34401A. Although the 34461A is way ahead of the 34401A in design, available functions, and the wonderful graphical display, there's one spec where the 34461A is much inferior: turn-on time. The 34401A is ready to go after three seconds of self-test, but the 34461A takes a full 55 seconds from the time I press the power switch to the time it is first usable. For an application where it will be data logging or connected to an ATE system, this probably doesn't matter, but sometimes I want to walk up to a DMM, turn it on, make a quick measurement, and be on my way. For this reason alone, I'll be keeping the 34401A.
Besides, why not have two (or more) 6-1/2 digit DMMs sitting on the bench? :-)
I've mentioned this problem to my distributor and they assure me that my comments will be passed on to Agilent. Whether it can or will be fixed is another question.
@Joe Thanks for the pointer to the new firmware. I installed it and you're absolutely right--the boot time is noticeably shorter (24 seconds!). I hope Agilent can make it even quicker with another firmware update. I really like the 34461A, and the only complaint that I have with it is that it's not "instant on" like all of my other DMMs.
There is a recommendation to leave the 34461A on 24/7 with the screen saver enabled: http://www.home.agilent.com/owc_discussions/thread.jspa?threadID=36071&tstart=0 "With a power consumption of 10W and a screen saver (Shift - Utility - System Setup - User Settings - Display Options - Scrn Svr) that dims the display following long periods of inactivity, it is recommended the 34460A/34461A DMM continually remain powered on."
Also, from a cold start, it takes some minutes to reach internal temperature stability (e.g. the ovenized reference) for use beyond about 5 digits.
One argument might be that boot-up time is on the order of a minimum time to use a partially "warmed up" DMM below spec (before full warm-up). The 34401A and newer 34410A also used ovenized references and have the same warm up needs.
On the other hand, when at the center of the bench, many of us use the DMM at hand for 3 1/2 to 4 1/2 digit quick measurements, which take very little warm up. Also, if one is working on an ATE setup (e.g. by LabVIEW), in early programming efforts, all that is needed is the DMM to be alive and responding.
I find the GUI of the 34461A to be outstanding. Like many others, we are hoping some day for a 61A style DMM that falls somewhere between the specs of the newer 34410A (the "10A") and the now ancient, but capable 3458A.