EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: iceisfun on August 31, 2013, 09:49:54 am
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Does it matter if scopes are left on?
DS2072, or maybe its a "2202" not sure ;)
I notice a lot of people seem to turn these off
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In a professional setup precision instruments are typically never turned completely off. It is also common that this is extended to any kind of non-handheld instruments in the lab. I remember an episode where a workshop supervisor even insisted on keeping the soldering irons powered, until health and safety told him in no uncertain terms to stop that because of the risk of fire, or to get fired. ;)
At home it is up to you. Part of my stuff is in a storage room and apparently not powered until I dig something out because I need it. I have a few precision references and meters running 24/7 in the lab, everything else gets turned off when not used. For low-end stuff like the Rigol I wouldn't be bothered to keep it running. I would not even trust that stuff to survive 24/7 (see the fun Dave recently had with the Rigol PSU).
But even if you don't keep any piece of equipment running intentionally, I highly recommend you install serious smoke/fire detection. The forgotten crap instrument going boom or the forgotten soldering iron, you know ... I also have a fire-proof door.
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I can see why you would want to keep a high-stability voltage reference or a frequency standard on all the time, but why would you keep a scope on? It's only going to degrade it faster.
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I build a small 230V distribution box for my bench that switches power to 4 powerstrips. It allows me to turn on groups of equipment with a single switch.
It's got 4 group and 1 main power switch with big neon. The neon make it really easy to check my desk at night. I don't have to inspect every device to check its off.
Brown switch = Bench power on/off
Main = soldering gear, power supplies, magify lamp
1st = generic test equipment (oscilloscope/siggen)
2nd = specialized test equipment (stuff i rarely use)
AUX = unused output for future use.
(http://psi.abcom.co.nz/pswitch.jpg)
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Most equipment reach thermal stability with in 30 minutes.
there is no point leaving on, unless your life depends on it.
Medical Equipment,
Defence Military Equipment.
Server & Hi class Motherboards lasts 50 years at <64°C,
but less than a Year, "5000hours" at 105°C.
Precision equipment has clocking devices,
age degrades accuracy in ppm/year.
Harddrives, have a power saving mode, spin down, windows controls at 20 minutes,
if you spin down more often say 1 minute idle, the harddrive will damage, too much turn-on/off, HDD needs 2Amps at turn-on.
if you leave-On all the time, harddrive will damage, too much heat, even IDLE eats only 0.6Amps.
most equipment have a 50.000hour life,
very high end equipment have up to 200.000hours of life.
decent equipment 70.000h.
moving parts degrade more easy.
All electronic equipment have a failure rate of 10%, Sony is proud of 5% failure of the PlayStation2.
Wrong designed equipment have a failure rate of 50%, for example: Thermaltake Dual 5G BlacX hard drive docking station,
but the Single 5G Thermaltake BlacX docking station is flawless. "i have 2, and want to buy the 3rd".
if the equipment is New, is better to burn-in or leave-on the 1st month, to see if it fails.
but...
if you need to turn-on your equipment many times a day, is better to leave-on.
Power Buttons that handle too much current degrade more easy, like high pressure h20 washing machines.
in the end all depends.
what kills life in the desert its the temperature differences: +45°C day, 0~(-3)°C night.
more stable temperature is better.
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I have 2 circuits feeding my home shop. One is constantly live which operates:
Digital Clock
DSL modem/router/WiFi and satellite TV gear (used for the whole house)
Line voltage/disturbance monitor
Rubidium frequency standard
Frequency counters x 2 (for internal crystal ovens)
HF receiver (internal crystal oven)
All the rest of the test gear (scopes, sig gens, power supplies, etc.) along with the bench outlets/soldering irons are powered through a contactor which is controlled by a start/stop pushbutton station near the door and an easily accessible emergency "scram" switch near the bench. The control power for this contactor is taken from the shop lighting circuit, so if I forget and leave a soldering iron on, it gets killed when the shop lights are shut off anyway.
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I don't think the Rb standard has to be kept running.... AFAIK it's reached full accuracy when it locks, right? You're just wearing it out.
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Does it matter if scopes are left on?
DS2072, or maybe its a "2202" not sure ;)
I notice a lot of people seem to turn these off
'Scopes? Probably not. Equipment with precision references should be left in standby. It took at least a week for the OCXO in my HP 5370A to settle down when only powered on (i.e. physically plugged in) during business hours. It would have been more like 72 hours if plugged in all the time.
Soldering irons? Turn 'em off. You'll only reduce the life of the tip by leaving them on and you'll keep the fire department happy. (We aren't allowed toasters in our office building, apparently due to fire codes... they are supposed to fire flaming rounds of bread after office hours and set fires as far as I could find out.)
Orin.
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I don't think the Rb standard has to be kept running.... AFAIK it's reached full accuracy when it locks, right? You're just wearing it out.
It depends on the model and what performance level you need. The last graph on this page shows one model of Rb standard that has some level of drift after locking although it looks like it's okay after 10 minutes. Retrace is also something that needs to be considered.
http://febo.com/pages/oscillators/rubes (http://febo.com/pages/oscillators/rubes)
You can argue that any electronic device will last longer if you only run it when necessary, but thermal stresses on start up and cool down affect lifetime. This is particularly true for something like an Rb standard that has parts that must run at temperatures from 70C to 100C. My Rb standard is my house standard that synchronizes multiple devices so it has to remain live at all times. I don't worry about it.
Ed
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Depends on your requirements. If its personal stuff at home, its probably best to turn them off.
It also depends on how much you use things. If my scope were on all the time, the electricity bill would increase and the CRT would ware out. If my meters were on all the time, the batteries would die.
The only thing I do tend to leave on is my computer, which I tend to want quick access to at all times of the day.
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If the manufacturer deemed it's something that should be left on (e.g. things with OCXOs in them) then the power switch is almost always a "standby" type. Your scope is not one of those things.
Back when I worked in a lab I had the rule that: anything with a CRT: off (/standy). Note that CRT wearout can occur even with intensity at minimum - depending on the CRT type.
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most equipment have a 50.000hour life,
very high end equipment have up to 200.000hours of life.
decent equipment 70.000h.
moving parts degrade more easy.
All electronic equipment have a failure rate of 10%, Sony is proud of 5% failure of the PlayStation2.
..
what kills life in the desert its the temperature differences: +45°C day, 0~(-3)°C night.
more stable temperature is better.
As I've done some hi-rel design, let me chime in here - those 50k or 200k hours you quote tend to be "calculated" MTBF, often not taking into account a host of operating conditions, they are based on numbers plugged into a spreadsheet by the egineering dept to make the marketing department happy.
Npw with regard to life-time are you better leaving things on or off - that depends. Consider, for example, red wine. There is some evidence that it's good for the cardiovascular system, when consumed in moderation, however, ethanol is bad for the liver hence a tradeoff. Similarly for electronic equipment: certain components, say electrolytics, have a finite lifetime that depends on age and temperature, this would favour switching equipment off, on the other hand, thermal warm-up/cool-down cycles are determental to solder joints - which would favaour keeping equipment switched on. Then there are factors like turn-on transients, which are design dependent.
But refer to my first post - unless you're working with that equipment every day, then switch it off / standby when not in use.