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Multimeter | Clamp meter | Insulation Resistance Tester | Panel Meter | Oscilloscopes | Test leads & Accessories | Software Updates => Bench-top Oscilloscope & Handheld scope meter => Topic started by: Kiriakos GR on April 02, 2013, 11:08:48 AM
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This video is the step by step guide of how to test the Waveform Update Rate on those GDS-2000A. 8)
The tricky point when you use a multimeter so to measure the frequencies of the Trigger output (on GDS-2000A) is that the output voltage is too low, and actually just above the 100mV, which brings in to play the sensitivity of your multimeter at the lowest AC volts range.
Usually the frequency counter on the good multimeter needs a minimum input voltage of 10 to 20% of AC volts in that specific working range, so to be triggered and operate (displaying and measuring frequency).
And so one multimeter with dedicated AC mV range has more chances to be sensitive enough for this measurement.
About good multimeter with out mV specified range in the range switch
They are also capable for measuring mV AC at their lowest AC volts range which is usually at 600mV.
Here comes in to play the sensitivity of the frequency counter regarding triggering,
when the meter operates at their lowest mV range.
There is a possibility your meter to not be sensitive enough for the specific measurement, and this fact it does not actually translate to that your meter has poor build quality.
Such details in the specifications of a multimeter usually they get ignored especially by electricians.
The people who design or test sound circuits (for example: a preamplifier), they are more careful about their multimeter selection regarding mV/Frequency counter sensitivity because such circuits has standard output levels starting from 150mV and moves up to 300mV or 600mV or more.
Listing of Multimeter with high sensitivity for the above frequency measurement==========
HIOKI DT4282 DMM ( measurements rate 7 or more per second)
Agilent U1272A & U1273A ( measurements rate about 3 per second)
Fluke 28II ( measurements rate one time every two seconds)
Megger AVO410 / BRYMEN BM-869 / DEREE DE-208A = not sensitive enough to activate the frequency counter.
Video.
https://youtu.be/-yS5YLWqf_Y
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As I saw your multimeter list above, I noticed huge differencies between them , about mesurement rates.
The point is that all of these meters, are in rather same quality/price class. What is your opinion about this?
Are these differencies acceptable for you?
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a) My point of view is that the word multimeter = many meters in one package,
it does justify such differences.
b) Every meter has its own personality or better said designed for specific applications.
c) Some Bloggers baptized meters made for electricians as for example the Fluke 87V or the 28II as best for electronics, which is fake info and a huge lie, Fluke does not have any medium priced meters specialized for troubleshooting in electronics.
d) Agilent made a huge step forward with those U1272A which are made for mixed use
1) Electrical
2) Industrial Electrical measurements &(VFD) motors.
3) Industrial electronics
This explains the why? those meters made such a huge positive impression to me.
I am an electrician which does electronics repairs too. :)
e) High quality meters made for electricians or industrial electricians which come loaded with special filters for Variable Frequency Drives (latest motors), or by performing at their specifications are worthy and honest at the same time.
f) The HIOKI DT4282 is currently the only strong opponent capable to challenge the U1270A series,
But it comes under a premium pricing.
Even so it is especially made for mixed use, my review it will shake the waters of marketing,
that's a promise. ;)
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Regarding the Waveform Update Rate measurement.
I just received my email from Agilent with one list of their latest Application Notes (material from my latest webinar about scopes).
Their document 5989-788EN is about their philosophy regarding Oscilloscope Waveform Update Rate and verification.
It looks clear that Agilent in their comparisons with other scopes, they recorded the Average readings and not the Max.
(Page 6) http://cp.literature.agilent.com/litweb/pdf/5989-7885EN.pdf (http://cp.literature.agilent.com/litweb/pdf/5989-7885EN.pdf)
And today by having all those information's which comes from two reliable sources,
I do feel ready to perform an similar type of measurements,
even by using the best-self of the DMM which belong to the ITTSB Showcase up to date. ;)