Author Topic: New Keithley DMM6500 and now DAQ6510  (Read 35453 times)

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Online hwj-d

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #350 on: Yesterday at 01:20:19 am »

Update:

As i see now, there is a big difference between Reference Manual 7510 and Reference Manual 6500:
  • the Links in the 6500 Manual are not working,
    (DMM6500-901-01 Rev. A / April 2018)
  • the Links in the 7510 Manual do!
So, the use of the above mentioned, extracted, intern correct linked HTML-Helpfile-Doc's for workflow TSP programming make sense, till the Reference Manual 6500 is corrected.
The hyperlinks in the manual are working fine for me with Adobe Acrobat, is anyone else have trouble?  Try downloading directly from Tek.com... 
Also, the TSB command help files are compiled from the same source the Reference Manuals are compiled from.  You can access the TSB version of the help directly without going through TSB with (in  Windows 10 at least): Windows Key > Keithley Instruments folder > TSB for 65XX Documentation.  Or, just keep the Reference Manual pdf open and jump back to page 17, where the TSP command list starts.


Hmm, that's weird.

Are there different Reference Manuals: DMM6500-901-01 Rev. A / April 2018?
Downloaded from:
https://www.tek.com/tektronix-and-keithley-digital-multimeter/dmm6500-manual/model-dmm6500-6-1-2-digit-bench-system-0

Look at pictures, green are real hyperlinks, red are no hyperlinks, only colored text.
 

Offline Brad O

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #351 on: Yesterday at 06:10:59 am »
Are those DigiV measurements with the 7510 or 6500?
I was working with 7510. It was necessary to indicate this.

It seems to me that they are very similar? Or is it not?
They are similar, but there are a few differences, this is one of them.  The 7510 has different specs for its timestamps when digitizing than the DMM6500/DAQ6510, (search for "timestamp" in the 7510 datasheet to see the lines I'll be mentioning) the timestamp resolution is 1ns for standard buffers so that's why you're seeing that small variation, the actual difference is probably less.  The timestamp accuracy is spec'd to "20ns between adjacent readings".  What it means is there's 20ns of uncertainty between adjacent readings, so two readings could potentially be 40ns apart, as you're seeing.  The reason for this discrepancy, incidentally, is that the 7510 uses different clocks for timestamps and digitized readings that sync up every so often.  In actuality, the digitized readings are probably much closer together than what the timestamps say, it's the timestamps with the uncertainty, not the readings.

The 120ns difference is most likely those 2 clocks syncing.  Rather than explaining that in the datahseet, it just says the "20ns between adjacent readings" is valid "with total buffer time <2 s", after that those larger timestamp differences may appear.  Once again, these specs are for the 7510, NOT the 6500/6510 which use the same clock for readings and timestamps.

With the settings I gave?  I see <100ns variation off of 1s between each reading.  I'll put together a script tomorrow for you to try.
It is very interesting. It looks like I do not notice some important nuance. I will try to show the results that I get.
Try this script I'm attaching (same deal, change .txt to .tsp and run on the instrument), it's the same one I described in this message.  It'll take 100 readings on the 10V DCV range each 1s apart, just to make sure you're not missing anything.  Like I said, I saw <100ns difference between timestamps, you should see somewhere around that.


Update:

As i see now, there is a big difference between Reference Manual 7510 and Reference Manual 6500:
  • the Links in the 6500 Manual are not working,
    (DMM6500-901-01 Rev. A / April 2018)
  • the Links in the 7510 Manual do!
So, the use of the above mentioned, extracted, intern correct linked HTML-Helpfile-Doc's for workflow TSP programming make sense, till the Reference Manual 6500 is corrected.
The hyperlinks in the manual are working fine for me with Adobe Acrobat, is anyone else have trouble?  Try downloading directly from Tek.com... 
Also, the TSB command help files are compiled from the same source the Reference Manuals are compiled from.  You can access the TSB version of the help directly without going through TSB with (in  Windows 10 at least): Windows Key > Keithley Instruments folder > TSB for 65XX Documentation.  Or, just keep the Reference Manual pdf open and jump back to page 17, where the TSP command list starts.


Hmm, that's weird.

Are there different Reference Manuals: DMM6500-901-01 Rev. A / April 2018?
Downloaded from:
https://www.tek.com/tektronix-and-keithley-digital-multimeter/dmm6500-manual/model-dmm6500-6-1-2-digit-bench-system-0

Look at pictures, green are real hyperlinks, red are no hyperlinks, only colored text.

Ahhh, I see what you mean, try clicking the page number instead of the function name, does that work?

I had to go ask manuals about this one, the tool our manuals department uses broke on those function links when the DMM6500 manual was compiled and no one noticed until after it was on the web.  The page numbers should work everywhere though, they're generated via a different method.  All those links will be fixed in the next manual update in March.
 

Online hwj-d

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #352 on: Yesterday at 10:10:07 am »
Quote
Ahhh, I see what you mean, try clicking the page number instead of the function name, does that work?

Thanks Brad, that's it. Besides this big "fake"-hyperlinks i didn't register the clickable page numbers at all.  ???

Quote
All those links will be fixed in the next manual update in March.

 :-+
 

Offline MegaVolt

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #353 on: Yesterday at 10:18:52 am »
The 7510 has different specs for its timestamps when digitizing than the DMM6500/DAQ6510, (search for "timestamp" in the 7510 datasheet to see the lines I'll be mentioning) the timestamp resolution is 1ns for standard buffers so that's why you're seeing that small variation, the actual difference is probably less.  The timestamp accuracy is spec'd to "20ns between adjacent readings".  What it means is there's 20ns of uncertainty between adjacent readings, so two readings could potentially be 40ns apart, as you're seeing.
Oh yes :( I don't read the fine print well.

OK :( +/- 20 ns meet specifications. But 100 ns is already beyond the specification. Plus in DCV modes, the spread is more than 100ns :(

Quote
The reason for this discrepancy, incidentally, is that the 7510 uses different clocks for timestamps and digitized readings that sync up every so often.  In actuality, the digitized readings are probably much closer together than what the timestamps say, it's the timestamps with the uncertainty, not the readings.
Is there any chance that this will be fixed in 7510? After all then all sense of timestamp is lost.

Plus it seems to me that the synchronization of two hours can explain a single time failure. But on the chart I see triple crashes. And in some modes, I can find more bad samples.

Quote
Try this script I'm attaching (same deal, change .txt to .tsp and run on the instrument), it's the same one I described in this message.  It'll take 100 readings on the 10V DCV range each 1s apart, just to make sure you're not missing anything.  Like I said, I saw <100ns difference between timestamps, you should see somewhere around that.
I ran this script from the device (just fixed BLOCK_MEASURE_DIGITIZE on BLOCK_MEASURE for the second block). And I got a constant error of 17.5 μs on each measurement and the peak to peak spread is the peak of 2500 ns.

Data in the attachment.
 


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