3458A Owners - Leave it running 24/7 or turn it off? - Page 1
Forum section: electronics / testgear

author: Tony_G
author_rank: Super Contributor
timestamp: September 06, 2017, 02:24:12 pm
content: Hey All,I was poking around the interwebs last night and I followed a chain of posts regarding whether to leave the 3458A on 24/7 or to turn it off.So I thought I'd ask what is the general consensus? I've seen posts saying that the voltage reference in the 3458A can "un-age" if it is left off but I've also seen posts saying that they can drift if left on - Everyone does seem to agree that a 3458A with a long run time will have better performance but I thought I'd see what other owners thought.Who leaves theirs on or off?TonyG

author: dr.diesel
author_rank: Super Contributor
timestamp: September 06, 2017, 02:58:05 pm
content: I personally leave my 3458As/K7510/K2450/K2010 on 24-7. But then again pretty much all of my equipment is busy logging something anyhow. One could probably also argue that you can't accurately estimate/calculate drift with an unknown or inconsistent on-time.Only time I kill power is when a big storm rolls through.

author: razberik
author_rank: Frequent Contributor
timestamp: September 06, 2017, 04:57:25 pm
content: I would let it run 24/7, but turn off display through GPIB.

author: Dr. Frank
author_rank: Super Contributor
timestamp: September 06, 2017, 09:55:26 pm
content: I've always turned off my 3458As, as the first one @ university, in the 1990ties, and also now, my private one.1) In Germany, electric power is very expensive, about 30 cents/ kWh2) The annual DCV stability is not specified, whether it's 24/7, or intermittently powered.The LTZ1000 at 45..65°C will definitely drift less, or not at all when not powered.At higher oven temperatures, hysteresis might occur when unpowered over longer time. (AN18?). This effect might exceed the Arrhenius drift.After powering up, a long time for stabilization is required, at least 4h, or better 1/2 day for optimum stability.Anyhow, the 3458A is no standard instrument (U, R), therefore external references, 10V and 10k are superior over 24/7 operation.4) Some power components like the fast comparators will die earlier when powered 24/7. These are unobtainium as of today.Powering down as often as possible will increase instruments life.Frank

author: TiN
author_rank: Super Contributor
timestamp: September 06, 2017, 11:53:48 pm
content: On 24/7 on all precision meters/sources (2002's, 3458s, 3245, 4920). But then they almost always log something. Both of my 3458A pimped up for 55C LTZ ref.

author: CalMachine
author_rank: Frequent Contributor
timestamp: September 07, 2017, 01:34:43 am
content: At the lab I leave everything running 24/7.

author: HighVoltage
author_rank: Super Contributor
timestamp: September 07, 2017, 07:22:27 am
content: I had my Keysight 34470A, the 10V Geller SVRT and my 7V LTZ reference ON for a couple years.The 3458A is off and only turned ON when needed.It is nice to see that it takes about the same time again and again to reach the same value, compared to the 34470A.

author: VK5RC
author_rank: Unknown
timestamp: September 11, 2017, 11:33:18 am
content: Turn mine off.Warm up = 24 hrs of switching on the 3458 and 24hrs of heating/cooling the room to 19-20C - humidity not a problem here - average room temp about 15- 17C left to its own devices. Most of the LTZ references are on continuously at present for a bit of a long term experiment (aiming for a few years).Rob

author: Mickle T.
author_rank: Frequent Contributor
timestamp: September 11, 2017, 08:05:24 pm
content: I had my 10/1/0.1V LTZ reference ON for a last six years.The 1271, 6581, 7081 LTZ-based DMMs are off and only turned ON when needed.

author: View[+]Finder
author_rank: Unknown
timestamp: November 24, 2017, 09:48:45 pm
content: If the 3458 is powered on, there is no power taken from the NVSRAM internal bettery and the battery will last a lot longer than 10-years. I have other Li cells with 10 years installed and over 10 years 'on the shelf' after that still showing proper volts. See my post elsewhere in this forum.