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Products => Test Equipment => Topic started by: bitseeker on May 22, 2016, 07:39:40 am

Title: Rigol DS1054Z calibration & adjustment
Post by: bitseeker on May 22, 2016, 07:39:40 am
Out of curiosity, I was doing some searching here and on the web at large regarding calibration/adjustment for the 1054 (i.e., not referring to the built-in auto-cal), but found nothing fruitful thus far. It may or may not need an adjustment in the coming years, but if it does, then what?

I don't think the usual calibration services handle these. I suppose Rigol would be happy to take your money. However, I only need it to be accurate relative to other instruments in my lab (i.e., adjusted to an in-house reference), not NIST. In other words, DIY calibration. :-/O

Given its price class, it might be considered relatively disposable. :o Is that its ultimate fate? I suppose it could go on living for qualitative see-if-something's-there use, should it actually drift so far from where it should be.

Mine is still under warranty, so I haven't taken it apart, yet. Just thinking aloud.  :blah:
Title: Re: Rigol DS1054Z calibration & adjustment
Post by: tautech on May 22, 2016, 07:46:06 am
It should be outlined in a Service manual, have you tried to find one?

TDS Teks in the past had a button press sequence to enter service mode in which each of the adjustable parameters could then be checked and adjusted against a known reference.

These days many DSO's a calibrated against the like of a Fluke scope calibrator, the model should be stated on your scopes Cal cert.
Title: Re: Rigol DS1054Z calibration & adjustment
Post by: bitseeker on May 22, 2016, 07:57:21 am
Yes, I've tried to find a service manual. Perhaps others have better Google-Fu than I. However, I vaguely recall a post or two about the lack of much technical information about these scopes. Hence, my ponderings.
Title: Re: Rigol DS1054Z calibration & adjustment
Post by: Fungus on May 22, 2016, 08:31:03 am
It may or may not need an adjustment in the coming years, but if it does, then what?
Is it out of spec now? If it isn't then there's no reason to think it ever will be.  :-//

I suppose it could go on living for qualitative see-if-something's-there use

That's actually its main purpose.

Oscilloscopes aren't multimeters. You shouldn't expect highly accurate voltage measurements from them.

Most DSOs use 8-bit ADCs attached to circuitry that's designed to respond to high frequencies. This means you have about 1% accuracy under ideal conditions (and that's only when your vertical gain is set so that the signal occupies the whole screen).

The specs for the DS1054Z are:
DC Gain Accuracy: <10 mV: ±4% full scale, ?10 mV: ±3% full scale
DC Offset Accuracy: ±0.1 div ±2 mV ±1% offset value

1% offset error + 3% gain error could add up to 4%. Add in the ADC error, improper vertical scale setting, some RF noise from the lights, imperfect probing, etc. and you can easily have 5-10% error in the on-screen numbers.

Bottom line: Oscilloscopes aren't multimeters.

(Yes, I'm sure there's some old green-screen "Tek" that's sub-1% accurate, but... )

Yes, I've tried to find a service manual. Perhaps others have better Google-Fu than I. However, I vaguely recall a post or two about the lack of much technical information about these scopes. Hence, my ponderings.

I doubt they have anything more than their self-calibration function.
Title: Re: Rigol DS1054Z calibration & adjustment
Post by: EI6JA on May 22, 2016, 05:02:56 pm
The Performance Verification Guide is available at http://beyondmeasure.rigoltech.com/acton/attachment/1579/f-0564/1/-/-/-/-/DS1000Z%20MSO1000Z%20Performance%20Verification%20Guide.pdf (http://beyondmeasure.rigoltech.com/acton/attachment/1579/f-0564/1/-/-/-/-/DS1000Z%20MSO1000Z%20Performance%20Verification%20Guide.pdf)
It does not cover adjustment but should let you know if your oscilloscope is within specification.

Title: Re: Rigol DS1054Z calibration & adjustment
Post by: uncle_bob on May 23, 2016, 12:14:19 am
Hi

I would not be surprised if there isn't much calibration on this scope. All of the timebase stuff is run off of a fixed crystal oscillator. If it's off ... replace it. All of the bandwidth stuff appears to be select at test parts. About all that leaves are the gains. At the precision of the scope, that may all be dependent on fixed ratio resistors. Again, if they are broke ... replace them.

Bob
Title: Re: Rigol DS1054Z calibration & adjustment
Post by: bitseeker on May 23, 2016, 01:53:15 am
Thanks for the insights. My prior scope was a CRO, so it was mostly a case of curiosity as to what the long run is like for a DSO. If it does end up just being component replacements, no big deal. Alas, with the way electronics are these days, it'll probably be replaced by some bigger fancier scope before it goes out of whack.
Title: Re: Rigol DS1054Z calibration & adjustment
Post by: tautech on May 23, 2016, 02:03:30 am
I doubt they have anything more than their self-calibration function.
::)

Thanks for the insights. My prior scope was a CRO, so it was mostly a case of curiosity as to what the long run is like for a DSO. If it does end up just being component replacements, no big deal. Alas, with the way electronics are these days, it'll probably be replaced by some bigger fancier scope before it goes out of whack.
To give you some idea of what's involved with a modern DSO check the SM for a basic Siglent DSO:

http://www.siglentamerica.com/Uploadfile/file/20140925/SDS1000CML_ServiceManual_en.pdf (http://www.siglentamerica.com/Uploadfile/file/20140925/SDS1000CML_ServiceManual_en.pdf)

Pages 26 & 27 list the gear needed and describe the steps involved in the process.
Title: Re: Rigol DS1054Z calibration & adjustment
Post by: bitseeker on May 23, 2016, 04:33:26 am
Thanks, tautech. Not much to it. Just click "test". :-DD Oh, wait. I need a Fluke 9500B.  :-BROKE

Even though there isn't a similar Rigol document handy, I'm sure it's something similarly automated.
Title: Re: Rigol DS1054Z calibration & adjustment
Post by: tautech on May 23, 2016, 05:05:48 am
Thanks, tautech. Not much to it. Just click "test". :-DD Oh, wait. I need a Fluke 9500B.  :-BROKE

Even though there isn't a similar Rigol document handy, I'm sure it's something similarly automated.
There will be but maybe not in the public domain.....yet.

One would expect the Self Cal process to flag a failure when it doesn't meet spec and warn the user that a full Calibration or repair is needed.

Depending on how involved and smart the Self Cal is it might even point to the failure, something like the warning in this post:
https://www.eevblog.com/forum/testgear/oh-no!-i'm-never-buying-any-agilent-keysight-equiment-ever-again!/msg945126/#msg945126 (https://www.eevblog.com/forum/testgear/oh-no)

Until you see warning flags......continue normal transmission.  ;)



Link fixed
Title: Re: Rigol DS1054Z calibration & adjustment
Post by: bitseeker on May 23, 2016, 06:05:30 am
Roger! Normal transmission transmitting...normally.