Author Topic: Narrowing down the correct scope  (Read 2164 times)

0 Members and 1 Guest are viewing this topic.

Offline PlasmateurTopic starter

  • Regular Contributor
  • *
  • Posts: 204
  • Country: us
Narrowing down the correct scope
« on: October 30, 2017, 02:45:50 am »
Hello,

After going through all the specs listed in the Digital Oscilloscopes Chart thread, I've narrowed my choices down to a few scopes.

The scopes are listed in the attachment.

Ideally I would use a PXI scope module from National Instruments, however they are cost prohibitive.

I need to be able to trigger the scope, quickly dump waveform data, and repeat multiple times.

Currently I'm using a tektronix DPO3054 for this application. When I acquire waveforms on all 4 channels with 1M data points, the whole process can take up to about 1.5 seconds...which is pretty much an eternity for me.

Does anyone here have experience with programming one of the scopes I've selected for repeated data acquisition, with a faster repetition rate than 1.5 seconds per trigger to acquisition? I would like to shorten this time by at least an order of magnitude if possible.

Thanks!



 

Offline PlasmateurTopic starter

  • Regular Contributor
  • *
  • Posts: 204
  • Country: us
Re: Narrowing down the correct scope
« Reply #1 on: October 30, 2017, 03:43:42 am »
Thank you for the response.

I'll contact their applications engineer tomorrow and see if they might have a ballpark figure on how long the process will take.
 

Offline ADT123

  • Regular Contributor
  • *
  • Posts: 71
  • Country: gb
    • Pico Technology
Re: Narrowing down the correct scope
« Reply #2 on: October 30, 2017, 06:45:02 am »
I am biased but if you are connecting to a PC / writing your own code and have been considering a PXI scope with no screen / display then consider also the PicoScope 6000 series:
https://www.picotech.com/oscilloscope/6000/picoscope-6000-overview                                                                                                                                                                               

Based on the specs you have highlighted the PicoScope 6402C is similar.  Cost is $3295, bandwidth is 250MHz (faster models available), sampling rate 5GS/s, memory is 256MS (up to 2GS available).  The waveform update rate is 170,000 per second or if you want to use rapid triggering / segmented memory then its trigger re-arm time is less than 1us so >1 million waveforms per second can be captured.

If you are writing your own software then the sped of data transfer back to the PC is important.  Using USB3.0 this is > 150MS/s. 



Disclaimer: I have worked for Pico Technology for over 30 years and designed some of their early oscilloscopes. 

We are always recruiting talented hardware and software engineers! Happy to answer Pico related questions when time permits but here as electronics is a hobby
 
The following users thanked this post: Someone, Plasmateur

Offline abraxa

  • Frequent Contributor
  • **
  • Posts: 377
  • Country: de
  • Sigrok associate
Re: Narrowing down the correct scope
« Reply #3 on: October 30, 2017, 08:32:45 am »
Quote
Currently I'm using a tektronix DPO3054 for this application. When I acquire waveforms on all 4 channels with 1M data points, the whole process can take up to about 1.5 seconds...which is pretty much an eternity for me.

How are you transferring the data? USB2? Ethernet? Which software?

The reason I'm asking is because scopes usually allow different data encoding schemes for the raw data values. In https://assets.tequipment.net/assets/1/26/Documents/Tektronix/dpo3000_programmermanual.pdf it says on page 57:
Quote
NOTE. You can use ASCII to obtain a readable and easier to format output than
binary. However, the oscilloscope may require [more] bytes to send the same values with
ASCII than with binary, reducing transmission speed.
The use of ASCII for waveform data transfer is inefficient.

So if you use ASCII encoding, the transfer time doesn't surprise me at all.

Depending on how quickly your "trigger the scope, quickly dump waveform data, and repeat multiple times" must happen, remote controlling the scope may be too slow. I'd be willing to bet that LeCroy's XDEV option provides the highest data throughput for any standalone scope - simply because you can write a C/C++ lib to directly interface with LeCroy's XStream software, both running on the scope itself. I'm not aware of anything comparable from Keysight or R&S, though that may have changed since the last time I checked.
http://teledynelecroy.com/options/productseries.aspx?mseries=289&groupid=144
 
The following users thanked this post: Plasmateur

Online nctnico

  • Super Contributor
  • ***
  • Posts: 27808
  • Country: nl
    • NCT Developments
Re: Narrowing down the correct scope
« Reply #4 on: October 30, 2017, 08:46:02 am »
Let's do some math first: 4x1Mpts =4MB. In 1.5 seconds means a transfer rate of 2.6MB/s. Most scopes won't be able to transfer that amount of data because they lack the processing power (the R&S RTB2000 can't even do half the datarate). How much data do you need in total? If the number of acquisitions is limited you could use segmented recording on a scope with a lot of memory.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 
The following users thanked this post: Plasmateur

Offline _Wim_

  • Super Contributor
  • ***
  • Posts: 1555
  • Country: be
Re: Narrowing down the correct scope
« Reply #5 on: October 30, 2017, 08:42:43 pm »
For fast streaming to a pc, I would use a PC digitizer card. Do not know what  the price is (nor have used something like this), but this can transfer data FAST:

https://spectrum-instrumentation.com/en/m4i2234-x8
 
The following users thanked this post: Someone, Plasmateur

Offline fonograph

  • Frequent Contributor
  • **
  • Posts: 369
  • Country: at
Re: Narrowing down the correct scope
« Reply #6 on: October 31, 2017, 07:17:51 pm »
Rte = lower noise,superior fft,bigger memory
Keysight = super fast,can be hacked

I definately go either Keysight 3000 or RTE,I prefer RTE becose it have lower noise and better fft,but keysight have fastest update rate and it can be hacked if its the non touchscreen version.

You have to be masochist to take Rigol over Keysight or R&S

BTW,there is 6000 euro RTO 1000 ex demo unit on R&S bargain site,its 600 MHz two channel,would buy that if I was you.

http://shop.rohde-schwarz.com/bargain/r-srrto1002-2.html



« Last Edit: October 31, 2017, 10:24:26 pm by fonograph »
 

Offline PlasmateurTopic starter

  • Regular Contributor
  • *
  • Posts: 204
  • Country: us
Re: Narrowing down the correct scope
« Reply #7 on: November 01, 2017, 05:58:48 pm »
Quote
Currently I'm using a tektronix DPO3054 for this application. When I acquire waveforms on all 4 channels with 1M data points, the whole process can take up to about 1.5 seconds...which is pretty much an eternity for me.

How are you transferring the data? USB2? Ethernet? Which software?

The reason I'm asking is because scopes usually allow different data encoding schemes for the raw data values. In https://assets.tequipment.net/assets/1/26/Documents/Tektronix/dpo3000_programmermanual.pdf it says on page 57:
Quote
NOTE. You can use ASCII to obtain a readable and easier to format output than
binary. However, the oscilloscope may require [more] bytes to send the same values with
ASCII than with binary, reducing transmission speed.
The use of ASCII for waveform data transfer is inefficient.

So if you use ASCII encoding, the transfer time doesn't surprise me at all.

Depending on how quickly your "trigger the scope, quickly dump waveform data, and repeat multiple times" must happen, remote controlling the scope may be too slow. I'd be willing to bet that LeCroy's XDEV option provides the highest data throughput for any standalone scope - simply because you can write a C/C++ lib to directly interface with LeCroy's XStream software, both running on the scope itself. I'm not aware of anything comparable from Keysight or R&S, though that may have changed since the last time I checked.
http://teledynelecroy.com/options/productseries.aspx?mseries=289&groupid=144

I am transferring the data via USB. All programing is done in LabVIEW. The data is in binary.
 

Offline PlasmateurTopic starter

  • Regular Contributor
  • *
  • Posts: 204
  • Country: us
Re: Narrowing down the correct scope
« Reply #8 on: November 01, 2017, 06:09:52 pm »
For fast streaming to a pc, I would use a PC digitizer card. Do not know what  the price is (nor have used something like this), but this can transfer data FAST:

https://spectrum-instrumentation.com/en/m4i2234-x8

This is exactly what I need. Thank you so much!
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf