EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: technix on January 07, 2017, 02:59:27 pm
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My first-paycheck gift to myself is a brand new Rigol DS1054Z. I gave it network access and have installed the hack and it is working properly as a DS1104Z. Is there any use and maintainence tops I need to be aware of?
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My first-paycheck gift to myself is a brand new Rigol DS1054Z. I gave it network access and have installed the hack and it is working properly as a DS1104Z. Is there any use and maintainence tops I need to be aware of?
The ground clip of the probes is connected to mains earth. Anything you clip it onto will therefore connect to mains earth. If what you're examining isn't floating then magic smoke can escape from it (nb. the scope should be OK unless you manage to pass enough amps to melt the probe lead).
On-screen numbers are calculated using the data on screen. For the most accurate readings always zoom in as much as possible on the area of interest (both height and width).
Apart from that, just read the manual and enjoy it.
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Just check if it has the latest firmware installed and have fun with it.
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Just check if it has the latest firmware installed and have fun with it.
My unit is running firmware 00.04.02.SP4 on hardware 0.1.1 (as reported in the system information screen.) Is it okay?
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My unit is running firmware 00.04.02.SP4 on hardware 0.1.1 (as reported in the system information screen.) Is it okay?
Seems very old to me. Latest official firmware is 00.04.04.00.07
Press this secret key sequence to get extended system info:
Menu -> Menu -> Force -> Menu -> Utility -> System -> System Info
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My unit is running firmware 00.04.02.SP4 on hardware 0.1.1 (as reported in the system information screen.) Is it okay?
Seems very old to me. Latest official firmware is 00.04.04.00.07
Press this secret key sequence to get extended system info:
Menu -> Menu -> Force -> Menu -> Utility -> System -> System Info
Where to find the latest one? And what key combination you are talking about? There are multiple Menu buttons.
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To display the full version information:
- In the trigger area on the front panel, press MENU > MENU > FORCE > MENU <<< press this sequence very quickly
- In the menu area, press UTILITY > SYSTEM > SYSTEM INFO
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Normally you can download the latest firmware here:
http://int.rigol.com/Support/SoftDownload/3 (http://int.rigol.com/Support/SoftDownload/3)
But Rigol removed it because there seems to be a problem with the latest version.
Conract Rigol for a firmware update and they will send you a link where you can download it.
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To display the full version information:
- In the trigger area on the front panel, press MENU > MENU > FORCE > MENU <<< press this sequence very quickly
- In the menu area, press UTILITY > SYSTEM > SYSTEM INFO
Here is the screen (in Chinese as I speak that language natively.)
(https://www.eevblog.com/forum/testgear/rigol-ds1054z-bandwagon-tips/?action=dlattach;attach=283731)
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Is there any use ... tops I need to be aware of?
As with any scope, the probes and probing technique are important, since they are part of the circuit and the oscilloscope.
Make sure you use the right type of probe for the task (e.g. HV, Z0, current, differential, isolating, active etc etc) and that you use it safely and correctly - particularly w.r.t. that fictional entity called "ground". Classic examples: a standard *10 "high" impedance probe self-resonates at ~100MHz, and at high frequencies its input impedance is lower than so-called low impedance Z0 probes.
FFI, see the references at https://entertaininghacks.wordpress.com/library-2/scope-probe-reference-material/
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Use 'x10' mode.
Don't try to use the probes in 'x1' mode until you understand why you're not supposed to do that.
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Like with any other equipment that can: Self Cal often.
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Talking about the ground issue: I found that the USB connector is able to power an Arduino or ESP8266, with common ground. So, would doing that and leaving out the ground clip entirely be a good idea? I guess starting at some frequency, you want to keep the loop small and use the short ground clip wire, but for a lot of stuff, this should work, shouldn't it? It wouldn't be the first time that I have a hard time finding a good position to place ground on a miniaturized µC board.
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Talking about the ground issue: I found that the USB connector is able to power an Arduino or ESP8266, with common ground. So, would doing that and leaving out the ground clip entirely be a good idea? I guess starting at some frequency, you want to keep the loop small and use the short ground clip wire, but for a lot of stuff, this should work, shouldn't it? It wouldn't be the first time that I have a hard time finding a good position to place ground on a miniaturized µC board.
I never really thought about doing that, the dev board is usually connected to a PC for software uploads.
There's no reason it won't work though. Give it a try and see what happens. Have a look at a square edge and see if you get more ringing (or not... If the entire board is at the same potential as the 'scope then I'm not sure what happens :o ).
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I never really thought about doing that, the dev board is usually connected to a PC for software uploads.
Sure, that should also work, as PC USB ports are also usually at earth potential. Just makes the loop even bigger.
I actually did it and it worked for the stuff I did, but that was basically digital stuff in the lower kHz region with not much interest in analog stuff (just got the osci and mainly finally debugged my IR hub). So I am not sure if that would really be a generally good tip are would fall apart very soon.
In Any case it is surely better that letting out the magic smoke by connecting the clip to the wrong contact.
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I never really thought about doing that, the dev board is usually connected to a PC for software uploads.
Sure, that should also work, as PC USB ports are also usually at earth potential. Just makes the loop even bigger.
Yes, it will work. I'm just worried you'll get a lot more ringing on fast rising edges (I think you will, otherwise what would be the point of the little spring thingy for the probe).
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I never really thought about doing that, the dev board is usually connected to a PC for software uploads.
Sure, that should also work, as PC USB ports are also usually at earth potential. Just makes the loop even bigger.
Yes, it will work. I'm just worried you'll get a lot more ringing on fast rising edges (I think you will, otherwise what would be the point of the little spring thingy for the probe).
Well I was seeing ringing even with the ground clip, probing a square wave right at the pin of a STM32F103 pushing out square wave with its PWM hardware.
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Well I was seeing ringing even with the ground clip, probing a square wave right at the pin of a STM32F103 pushing out square wave with its PWM hardware.
Try using the spring (see other thread), it really helps.
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Like with any other equipment that can: Self Cal often.
Heh... whenever you have a spare hour, anyway.
Warm it up for 30 minutes first, then run the self-cal routine.... and it takes 17-19 minutes to complete the self-cal.
The instrument is indeed sensitive to changes in ambient temperature. I get DC offsets appearing whenever the room temperature changes by a couple of degrees.
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To display the full version information:
- In the trigger area on the front panel, press MENU > MENU > FORCE > MENU <<< press this sequence very quickly
- In the menu area, press UTILITY > SYSTEM > SYSTEM INFO
Here is the screen (in Chinese as I speak that language natively.)
(https://www.eevblog.com/forum/testgear/rigol-ds1054z-bandwagon-tips/?action=dlattach;attach=283731)
Hah... I see you have Boot Version 0.0.1.2. Unfortunately there seems to be no way for the _user_ to upgrade the Boot Version. The "firmware" updates that we can install only change the "software version".
Since you have that early Boot Version and are still running an older "firmware" version, you may still be susceptible to certain bugs that were found, like the Freeze Bug and the Measurements Fail bug. There are threads talking about these bugs if you want to check for them.
You should also know about the "fifth grey button reset" if your scope ever freezes and becomes non-responsive.
Press this button repeatedly during the bootup process, and the scope will reset to "factory defaults":
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Like with any other equipment that can: Self Cal often.
Heh... whenever you have a spare hour, anyway.
Warm it up for 30 minutes first, then run the self-cal routine.... and it takes 17-19 minutes to complete the self-cal.
The instrument is indeed sensitive to changes in ambient temperature. I get DC offsets appearing whenever the room temperature changes by a couple of degrees.
Really ? :scared:
Shite that's slow.
Let me do one for a 1102X, bet it's under 4 minutes......I lost...4 min 5 sec.
SDS2304X........2 min 47 sec, but these have a Quick Cal too that Cal's on the fly. Haven't used it for a long time but IIRC it takes just a few seconds.
No restarts required for either series of these, if fact AFAIK any of the Siglent DSO range.
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Just ran a self-cal to check for certain:
Start time 23:06:30
End time 23:25:01 (not including restart after calibration routine finishes)
This is the third DS1054z unit I've had in my possession and all of them have taken about that long to self-cal.
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Really ? :scared:
Shite that's slow.
Let me do one for a 1102X, bet it's under 4 minutes....
I feel pitty for you that you are so desperately trying to promote your siglent stuff in every thread here.
Is business going that bad for you?
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Let me do one for a 1102X, bet it's under 4 minutes......I lost...4 min 5 sec.
That only has 2 channels... DS1054Z has 4! :popcorn:
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Really ? :scared:
Shite that's slow.
Let me do one for a 1102X, bet it's under 4 minutes....
I feel pitty for you that you are so desperately trying to promote your siglent stuff in every thread here.
:-DD
What's the matter Karel ?.....do the facts hurt ?
Confirmation by alsetalokin4017 indicates the Self Cal process of 1054Z's is pitifully slow. Period.
I've not seen it mentioned before, why shouldn't I comment ?
Is business going that bad for you?
It's excellent, 2016 was a record year. How about you ?
Let me do one for a 1102X, bet it's under 4 minutes......I lost...4 min 5 sec.
That only has 2 channels... DS1054Z has 4! :popcorn:
SDS2304X........2 min 47 sec
So somebody with a DS2072A chime in with their Self Cal time and then there can another for fair comparison.
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Have a look here:
Dave made a nice video how not to blow up you precious toy ;-)
https://www.youtube.com/watch?v=xaELqAo4kkQ (https://www.youtube.com/watch?v=xaELqAo4kkQ)
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Really ? :scared:
Shite that's slow.
Let me do one for a 1102X, bet it's under 4 minutes....
I feel pitty for you that you are so desperately trying to promote your siglent stuff in every thread here.
Is business going that bad for you?
Honestly I don't see a problem with his post. Almost 20 minutes to cal the scope is crazy long. Even my old Tek does SPC in less than 5 minutes for 4 channels. I haven't timed it exactly but I know it's in the 3-4 minute range from just watching the clock waiting for it. That kind of info is useful to new or potential users - I sure would like to know that before purchasing - it would be an unhappy surprise to me. It doesn't kill the scope in my eyes by any means, but geez that's almost an hour before you can trust measurements.
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Without knowing what the self calibration covers (does) it doesn't make sense to compare the time.
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That kind of info is useful to new or potential users - I sure would like to know that before purchasing - it would be an unhappy surprise to me. It doesn't kill the scope in my eyes by any means, but geez that's almost an hour before you can trust measurements.
So? The Siglents and Teks need more than 45 minutes. That's not really much better, is it? :popcorn:
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That kind of info is useful to new or potential users - I sure would like to know that before purchasing - it would be an unhappy surprise to me. It doesn't kill the scope in my eyes by any means, but geez that's almost an hour before you can trust measurements.
Hmm... How often do you guys typically run self-calibration?
My espresso machine needs to be descaled occasionally, and I couldn't care less how long that takes, as long as the coffee tastes good. ;) I have always considered scope self-cal to be in a similar class of operation: Do it once or twice a year, or maybe if you move the scope to a different environment. (Say outdoors -- but I have not had that need yet.) Are you using it much more often?
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That kind of info is useful to new or potential users - I sure would like to know that before purchasing - it would be an unhappy surprise to me. It doesn't kill the scope in my eyes by any means, but geez that's almost an hour before you can trust measurements.
Hmm... How often do you guys typically run self-calibration?
Me? Almost never. Maybe after a firmware update or when winter/summer arrives.
I never imagined my scope as a multimeter, I know the voltage readings are only about 5% accurate even when perfectly calibrated (it says so in the manual!)
If you know that simple fact you can relax and use it for what it's meant to be used for, ie. look at the wiggly lines and see if they're the right shape or not.
5% accuracy is enough to see if there's a problem in the circuit. Everything else is just volt-head obsessing.
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That kind of info is useful to new or potential users - I sure would like to know that before purchasing - it would be an unhappy surprise to me. It doesn't kill the scope in my eyes by any means, but geez that's almost an hour before you can trust measurements.
Hmm... How often do you guys typically run self-calibration?
Maybe once every 2 years. Probably when I notice the DC offset at the mV/division ranges is a bit off.
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I am recalibrating only after a firmware update. Recalibrating time is not important, since you need to let the scope to properly heat for at least 1/2 hour before recalibrating. Otherwise, repeated recalibration is pointless.
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Thanks, all. That makes me feel better. So I will keep doing what I've been doing (or rather not doing) regarding self-calibration... And I will keep not caring at all how long it takes. ;)
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That kind of info is useful to new or potential users - I sure would like to know that before purchasing - it would be an unhappy surprise to me. It doesn't kill the scope in my eyes by any means, but geez that's almost an hour before you can trust measurements.
So? The Siglents and Teks need more than 45 minutes. That's not really much better, is it? :popcorn:
:wtf:
Typo I guess, otherwise no idea where you got 45 mins from ? |O
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geez that's almost an hour before you can trust measurements.
So? The Siglents and Teks need more than 45 minutes. That's not really much better, is it? :popcorn:
:wtf:
Typo I guess, otherwise no idea where you got 45 mins from ? |O
Nope, just basic math.
If the 17-minute Rigol takes "almost an hour" to calibrate then the original poster must have done a 42 minute warmup.
With the same math the 4-minute Siglent takes over 45 minutes.
The Siglent is therefore 23% faster.
Not exactly a showstopping difference is it? :-//
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:wtf:
Typo I guess, otherwise no idea where you got 45 mins from ? |O
Warmup time plus a few minutes for the actual self-calibration, I assume.
No cause to get overly excited, tautech. Don't hurt your head there...
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:wtf:
Typo I guess, otherwise no idea where you got 45 mins from ? |O
Warmup time plus a few minutes for the actual self-calibration, I assume.
No cause to get overly excited, tautech. Don't hurt your head there...
:)
In the many years I've had DSO's (Teks and Siglents) none have had Self Cal times or more than 5 minutes, 2 or 4 ch models. Period.
Self Cal is not something one uses every day or even during an extended period of use unless there's some reason for it like a "sanity check" because the measurements captured aren't what you'd expect. In this case while using the instrument and a Self Cal seems necessary a short break while it happens for a coffee is fine but a whole lunch break for it to finish. :o :wtf: :--
Should Siglent present the market with a entry level DSO that takes more than a few minutes to run a Self Cal, I won't be selling it and they'll get told to sort it out. :box:
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Running the self calibration daily is severe overkill. On some oscilloscopes (Agilent DSO7000 series for example) running the self calibration even voids the calibration performed by a calibration lab. Hooking the probes to the calibrator output and check if the signal is OK is even better because you'll also test the probes.
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Running the self calibration daily is severe overkill.
Agreed.
On some oscilloscopes (Agilent DSO7000 series for example) running the self calibration even voids the calibration performed by a calibration lab.
How can that be ? :-//
If the conditions that the Cal was performed in are replicated (ambient temp, warm up time) and the official traceable Cal has nulled the internal reference errors, why would a Self Cal void any official Cal ? :-//
I don't get it.
Might there be a bug in the Agilent DSO7000 Self Cal ?
Is there a note from Agilent that explains this behaviour and why it is so ?
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If the conditions that the Cal was performed in are replicated (ambient temp, warm up time) and the official traceable Cal has nulled the internal reference errors, why would a Self Cal void any official Cal ? :-//
I don't get it.
One word: "Lawyers".
Pushing a "self cal" button doesn't prove it's working properly.
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Running the self calibration daily is severe overkill.
Agreed.
On some oscilloscopes (Agilent DSO7000 series for example) running the self calibration even voids the calibration performed by a calibration lab.
How can that be ? :-//
If the conditions that the Cal was performed in are replicated (ambient temp, warm up time) and the official traceable Cal has nulled the internal reference errors, why would a Self Cal void any official Cal ? :-//
I don't get it.
Might there be a bug in the Agilent DSO7000 Self Cal ?
Is there a note from Agilent that explains this behaviour and why it is so ?
Not really but the manual says a performance verification has to be performed after a self cal using equipment with traceable calibration to make sure the oscilloscope meets it's specifications.
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Running the self calibration daily is severe overkill.
Agreed.
On some oscilloscopes (Agilent DSO7000 series for example) running the self calibration even voids the calibration performed by a calibration lab.
How can that be ? :-//
If the conditions that the Cal was performed in are replicated (ambient temp, warm up time) and the official traceable Cal has nulled the internal reference errors, why would a Self Cal void any official Cal ? :-//
I don't get it.
Might there be a bug in the Agilent DSO7000 Self Cal ?
Is there a note from Agilent that explains this behaviour and why it is so ?
Not really but the manual says a performance verification has to be performed after a self cal using equipment with traceable calibration to make sure the oscilloscope meets it's specifications.
Hmmm.
Weird, I would call that a bug.
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Hmmm.
Weird, I would call that a bug.
Here we see why the DS1054Z "bug" list is so long - anything outside of somebody's personal expectations must be a bug! :popcorn:
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Hmmm.
Weird, I would call that a bug.
Here we see why the DS1054Z "bug" list is so long - anything outside of somebody's personal expectations must be a bug! :popcorn:
::)
You need to do some more study why equipment have Self Cal capability and why there is a need to use it occasionally.
Measurements are affected by primarily temperature and the combination of runtime and ambient might not equate to the temp when equipment was calibrated and if this is the case that Cal will not be valid. Component drift from aging is another factor and why manufacturers recommend yearly calibration for traceable accuracy.The best we have between annual calibration for those that require it is a Self Cal feature to null these temp discrepancies to make measurement more accurate. If it doesn't one can only assume the Self Cal routines themselves are flawed. :-BROKE
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Running the self calibration daily is severe overkill.
Agreed.
On some oscilloscopes (Agilent DSO7000 series for example) running the self calibration even voids the calibration performed by a calibration lab.
How can that be ? :-//
If the conditions that the Cal was performed in are replicated (ambient temp, warm up time) and the official traceable Cal has nulled the internal reference errors, why would a Self Cal void any official Cal ? :-//
I don't get it.
Might there be a bug in the Agilent DSO7000 Self Cal ?
Is there a note from Agilent that explains this behaviour and why it is so ?
Not really but the manual says a performance verification has to be performed after a self cal using equipment with traceable calibration to make sure the oscilloscope meets it's specifications.
Hmmm.
Weird, I would call that a bug.
On a scope with a US $25k list price for the basic configuration from a manufacturer with over half a century of experience with manufacturing oscilloscopes? I don't think so.
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Running the self calibration daily is severe overkill.
Agreed.
On some oscilloscopes (Agilent DSO7000 series for example) running the self calibration even voids the calibration performed by a calibration lab.
How can that be ? :-//
If the conditions that the Cal was performed in are replicated (ambient temp, warm up time) and the official traceable Cal has nulled the internal reference errors, why would a Self Cal void any official Cal ? :-//
I don't get it.
Might there be a bug in the Agilent DSO7000 Self Cal ?
Is there a note from Agilent that explains this behaviour and why it is so ?
Not really but the manual says a performance verification has to be performed after a self cal using equipment with traceable calibration to make sure the oscilloscope meets it's specifications.
Hmmm.
Weird, I would call that a bug.
On a scope with a US $25k list price for the basic configuration from a manufacturer with over half a century of experience with manufacturing oscilloscopes? I don't think so.
::)
Do you mean the same manufacturer that makes these too ?
https://www.eevblog.com/forum/testgear/agilent-dsox2024-won't-boot/ (https://www.eevblog.com/forum/testgear/agilent-dsox2024-won't-boot/)
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Since I don't use the scope too often, I think I am going to deploy an automated weekly or monthly self-cal.
The scope have Ethernet connectivity so self cal can be initialized and queried by my always-on server. Just power the scope with an Ethernet-enabled power strip (so I can bypass the clunking power button, leaving it always on, and switch the power to it in software)
I need to cook up software for this task, and set up a cron job on my server to run it periodically.
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That kind of info is useful to new or potential users - I sure would like to know that before purchasing - it would be an unhappy surprise to me. It doesn't kill the scope in my eyes by any means, but geez that's almost an hour before you can trust measurements.
Hmm... How often do you guys typically run self-calibration?
My espresso machine needs to be descaled occasionally, and I couldn't care less how long that takes, as long as the coffee tastes good. ;) I have always considered scope self-cal to be in a similar class of operation: Do it once or twice a year, or maybe if you move the scope to a different environment. (Say outdoors -- but I have not had that need yet.) Are you using it much more often?
That is true. I suppose my head is just spinning from the handheld debacle I'm dealing with. It won't hold its calibration for more than a minute.
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Me? Almost never. Maybe after a firmware update or when winter/summer arrives.
I never imagined my scope as a multimeter, I know the voltage readings are only about 5% accurate even when perfectly calibrated (it says so in the manual!)
If you know that simple fact you can relax and use it for what it's meant to be used for, ie. look at the wiggly lines and see if they're the right shape or not.
5% accuracy is enough to see if there's a problem in the circuit. Everything else is just volt-head obsessing.
Yes. This, absolutely.
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I suppose my head is just spinning from the handheld debacle I'm dealing with. It won't hold its calibration for more than a minute.
To be fair eKretz, the issue you're experiencing with your Micsig really has nothing much to do with holding calibration. You seem to have had bad luck getting a Micsig handheld with an issue that needs to be resolved but it is not really a calibration issue per se.
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Since I don't use the scope too often, I think I am going to deploy an automated weekly or monthly self-cal.
The scope have Ethernet connectivity so self cal can be initialized and queried by my always-on server. Just power the scope with an Ethernet-enabled power strip (so I can bypass the clunking power button, leaving it always on, and switch the power to it in software)
I need to cook up software for this task, and set up a cron job on my server to run it periodically.
Hey, glad you are still following this thread! Apologies for having spent so much time on the self-calibration, which is certainly not the most important topic to familiarize yourself with in your new scope.
I don't think it is worthwhile to invest so much effort in an automated, periodic self-calibration setup. The consensus here seems to be that doing it once per year is enough, especially if your scope remains on the bench under stable ambient conditions.
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That kind of info is useful to new or potential users - I sure would like to know that before purchasing - it would be an unhappy surprise to me. It doesn't kill the scope in my eyes by any means, but geez that's almost an hour before you can trust measurements.
Hmm... How often do you guys typically run self-calibration?
Me? Almost never. Maybe after a firmware update or when winter/summer arrives.
I never imagined my scope as a multimeter, I know the voltage readings are only about 5% accurate even when perfectly calibrated (it says so in the manual!)
If you know that simple fact you can relax and use it for what it's meant to be used for, ie. look at the wiggly lines and see if they're the right shape or not.
5% accuracy is enough to see if there's a problem in the circuit. Everything else is just volt-head obsessing.
I'd change the last sentence to "Everything else is using the wrong tool for the job".
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Since I don't use the scope too often, I think I am going to deploy an automated weekly or monthly self-cal.
The scope have Ethernet connectivity so self cal can be initialized and queried by my always-on server. Just power the scope with an Ethernet-enabled power strip (so I can bypass the clunking power button, leaving it always on, and switch the power to it in software)
I need to cook up software for this task, and set up a cron job on my server to run it periodically.
You could do that, but it won't make anything better. Devices don't decalibrate themselves on time spans measured in weeks/months, it takes many years if it's in a stable environment.
A much better action plan is to grok the idea that the voltage readings on screen are only approximate. Good enough to see if there's a problem but that's all.
Use a multimeter for important measurements (aka "the right tool for the job").
Here's some numbers for your perusal, taken from the DS1054Z manual:
(https://www.eevblog.com/forum/testgear/rigol-ds1054z-bandwagon-tips/?action=dlattach;attach=284447;image)
(I just saw a typo in the manual - "Analog channe" :o )
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You need to do some more study why equipment have Self Cal capability and why there is a need to use it occasionally.
Measurements are affected by primarily temperature and the combination of runtime and ambient might not equate to the temp when equipment was calibrated and if this is the case that Cal will not be valid.
Any calibration needs to be verified. What if the internal voltage reference is broken? What if you didn't warm it up properly?
For corporate use, don't mess around. No boss wants legal liability because some intern pressed 'calibrate' every day right after he switched on all the test gear.
For hobby use I say go ahead and calibrate it yourself. Maybe verify it against a multimeter. Just don't imagine that frequent calibration will make the slightest bit of difference in real terms.
Maybe you work in a place that's freezing cold in the mornings and baking hot in the afternoons after The Machine has been on for several hours. You could calibrate twice a day, or... just relax and accept that the numbers on screen won't be exact even if you do that. You want exact numbers? Get a bench multimeter with temperature compensation, ie. the right tool for the job.
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Since I don't use the scope too often, I think I am going to deploy an automated weekly or monthly self-cal.
The scope have Ethernet connectivity so self cal can be initialized and queried by my always-on server. Just power the scope with an Ethernet-enabled power strip (so I can bypass the clunking power button, leaving it always on, and switch the power to it in software)
I need to cook up software for this task, and set up a cron job on my server to run it periodically.
You could do that, but it won't make anything better. Devices don't decalibrate themselves on time spans measured in weeks/months, it takes many years if it's in a stable environment.
A much better action plan is to grok the idea that the voltage readings on screen are only approximate. Good enough to see if there's a problem but that's all.
And I'd take that further, and try to get the people into the frame of mind that all readings from every instrument are approximate. The questions are how approximate, and what does the application require[1]
I have a suspicion that if someone measures voltages with a scope, they will also not understand probes, probing techniques, and the consequent lies you will see on a scope's screen.
[1]My favourite example is an expensive piece of test equipment with a resolution of 0.001dB but an accuracy of only 0.1dB. Guess which wasn't important in that application!
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For corporate use, don't mess around. No boss wants legal liability because some intern pressed 'calibrate' every day right after he switched on all the test gear.
Just so.
That's why many instruments disable the "cal button" unless an internal jumper is in the right position. Good thing too.
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Also: You might have to use somebody else's oscilloscope one day.
Is that oscilloscope going to be calibrated? :-//
What will you do if you see 4.8 volts where it should say 5.0V? :scared:
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Since I don't use the scope too often, I think I am going to deploy an automated weekly or monthly self-cal.
The scope have Ethernet connectivity so self cal can be initialized and queried by my always-on server. Just power the scope with an Ethernet-enabled power strip (so I can bypass the clunking power button, leaving it always on, and switch the power to it in software)
I need to cook up software for this task, and set up a cron job on my server to run it periodically.
Hey, glad you are still following this thread! Apologies for having spent so much time on the self-calibration, which is certainly not the most important topic to familiarize yourself with in your new scope.
I don't think it is worthwhile to invest so much effort in an automated, periodic self-calibration setup. The consensus here seems to be that doing it once per year is enough, especially if your scope remains on the bench under stable ambient conditions.
It sits on my desk where sunlight can reach. So probably not that stable ambient.
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Be careful of ground. Consider getting a differential probe for ungrounded and higher voltage work (such as power supplies).
BTW - One can utilize scopes, or a DMM, or any other device, for critical measurements (for example, you are measuring a single occurrence that will not happen again, or too costly to make happen again; or Need to refer to a physical property accurately like volt, ampere, ohm, Hz, SPL, lumens, etc. ; or Need great resolution for a very sensitive sensor).
Usually these types of measurements are run against external calibration. The simplest example (for a DMM) is if I work on mains I stuff the DMM in working mains. I don't trust a 0V shown until I am calibrated at 220v. It is even better to go back to the 220V and validate the DMM did not die between the two outlets... (It is critical because if the measurement is wrong I won't be around to do it again - becoming a 1 time measurement....)
Doing DC or ohms - compare against a fresh 9V battery (or better yet - a silver oxide battery) or a calibrator, measure a precision resistor salvaged from discarded T&M (in the same range as the DUT).
One can do the same with a scope. If one channel is down and both measure 4.8V instead of 5V - then the voltage isn't a clue. However, if one is 4.8v and the other reads 5v - it may be (per Fungus' post). The second (working) channel serves as a calibration reference against the first.
One can also work around limitations: If one is aware of the noise floor, one can raise the input signal for a good SNR using a calibrated amplifier. Use a mixer (properly) to work around bandwidth limitations, Etc. the options are endless...
Getting calibrated readings can get pretty complex pretty quickly - I did lots of these types of experiments in the Navy - it was all about calibrating the T&M chain. The hydrophone, the B&K charge amplifiers, the parametric and notch filters, the scopes, the recorders, the HP TRMS voltmeters, you had to plot and save a bathymetry (and work the predictions), plan the test with the operations team so that you know distances and depths fairly accurately, etc. In the ocean, everything needs to end up as dB re 1uPa @ 1yd in defensible accuracy.
Heck - eve a bad grounding scheme can destroy your test. So we'd calibrate the individual components and the setup as a whole for weeks prior to the live sea tests (and calibrate backup T&M in case something fell in the ocean - or decided to throw a tantrum) - Imagine the cost of redoing a test with a frigate or submarine because you could not figure out the SONAR equation...