I'm curious about what others think, very common in this lab for techs to go home at night and leave equipment powered up, RF outputs are off and that sort of thing but crt/lcd displays are on, fans running and guts cooking.
On one hand there is some equipment that is probably better left idling, Fluke 9500B come to mind and all those relays that are clicking every time it powers up from cold, but some manuals I have seen will suggest cal interval like 12 months or 2000 hours.
This is not a clean room environment and as the person charged with taking care of the stuff I am well aware that running fans are sucking in dust that makes some impressive deposits after 12 or more months.
I suppose there is also a balance of energy consumption/cost vs. trauma of power up on the equipment.
What say the board?
It varies with me...and it is the customer's equipment that usually will be left on..but, I try to know the customer and how they use thier equipment. The satellite communications shop leaves thier stuff on 24/7, because that's thier operation. Many of the aircraft shops leave thier stuff in the aircraft over night with the planes shut down. Others don't use it, and it sits on the shelf for the entire cal cycle. So, I think it comes down to knowing who you are supporting.
Mike
I think we end up leaving a lot of it on 24/7. But for the non-precision stuff (oscilloscopes, lower end DMM's etc) I try and turn it off. Things like high cost spectrum analyzers, I like the idea of turning off, especially if it is a little older. If it stays plugged in and has a high stability oscillator (such as our old HP 8566B, or our HP 89441A), they stay plugged in to keep the time base warm, but turned off.
High end DMMs (Fluke 8508A and HP 3458A), I leave on all the time. I've even heard from Agilent that the HP 3458A if left unplugged for a long time (6 -12 months or more), you can lose the characteristic stability of the zener oven, and it needs to find a new stability point. Kind of like how you should never power down a Fluke 732A/B etc.
Some of the general test equipment we even take off the benches when not in use and put in spare standards shelving.
Everything is turned off here except for 3458A option 002's and Fluke Calibrators
We leave our calibrators (5720's, 5520, etc) powered, as well as reference DMM's. Additionally, anything with a mfr recommended warm-up of >1 hour is left powered. All others either of or standby.
We leave our calibrators, high end meters, Cal stations, Pressure controllers and our DC / resistance standards on 24/7. The rest of the equipment (Distortion , Spectrum ananlyzers, bench meters & scopes )we shut down when we leave for the night.
I often wonder myslef if it is better to leave stuff on or shut it off. On the one hand you would think leaving your Fluke on all the time would put extra strain on the components on the other hand turning them on and off also probably produces some level of strain. I generally shut mine down when not in use. I have had pretty good luck so far with my standards (knocks on wood)
We leave the primary standards on (3458 OPT 2, 8508A, 5790A, 5720A) and that is it everything else is turned off. It help tremendously on the electric bill.