Questions about series 5000 & software

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electrolyte
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Questions about series 5000 & software

Post by electrolyte » Mon Sep 10, 2018 7:44 pm

Hello, i am looking for a platform to acquire a lot of data for measurements and calculations. Ideally done on the hardware, but when not possible done on a computer. The focus in my case is research rather than engineering. The 5000 series seems to fit my needs pretty well and the high resolution mode is a feature i really like. There are a few points about which i have not found as much information i needed. Maybe someone here can help me.

1. I have downloaded the software to play around in the demo mode. Using linux i realized, that it has not the complete feature support like the windows version. Will this change in the future?

2. Using the measurements i can have a look at statistical data. This provides a simple table with some information. In demo mode i can capture 1000 events, about 10 every second, to used in statistic calculations.
The speed changes when i change the amount of samples to be stored, although the sampling speed changes too.
Is this just a thing in the demo? I think the counting should be as fast as the scope updates a waveform, because (i assume) that a measurement is made on every acquisition. So can i expect a picoscope to count the measurements as fast as the waveform update rate and can i capture more than demo 1000 points in the demo?

2a. I am looking for a scope to do some really in depth analysis. Can all the measured and via statistics collected data be exported for further processing?
For example: Having 5 different measurements on signals or math traces. Each saves up to 50 million values for every measurement.

3. In one thread there is mentioned how the USB connection is not a bottleneck and i really like the approach on this solution. I had a look in the programmers user guide to see how good raw data can be exported to the computer.
The way one would do this is the rapid block mode i suppose. The manual says, that the gap between waveforms is less than 2 microseconds on the lowest time base. Is this the time in which the trigger is re armed to enable the scope to do another acquisition? How does it look like on different time bases?
Is such a situation possible:
Scope is setup to acquire on each trigger 200 samples with 16 bit at 62.5Msp/s. When the memory is full, all raw data gets transmitted and the process starts again. Time between waveforms lower than 2 microseconds.

3a. What is the transfer speed when transmitting raw data like in example 3. to a pc? USB 3.0 is specified to 5Gbit/s, but i am curious how much is possible to archive with a real setup.

I hope someone can help me with some detailed information :).

Hitesh
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Re: Questions about series 5000 & software

Post by Hitesh » Tue Sep 11, 2018 10:27 am

Hi electrolyte,

To answer your questions:

1. We are working towards feature parity between the Windows, Linux and macOS versions although this will not be available until the next major release (no timescales at present).

2. You can capture up to a maximum 10,000 waveforms using the PicoScope software (depending on the sampling settings for the device - see the General tab in the Tools -> Preferences dialog). The measurements feature is a post-processing operation on the data collected.

2a. The measurements table can be exported to file using automation commands. If you use the DeepMeasure feature you can export the table to file from the user interface.

3. In rapid block mode, the gap between captures is the time it takes to rearm the trigger again. If you use longer timebases, it will take longer to re-arm as it takes a while for the trigger to be detected.

If you are using the API functions, you have to segment the memory and then specify the number of captures. Once the set of captures is complete you need to retrieve the data from the device and start again.

3a. The transfer speed might depend on your PC configuration/overheads. It should be a lot quicker than the 14 seconds quoted in the Programmer's Guide for a USB 2.0. I'll see if I can find out and get back to you.

Hope this helps,
Hitesh

Software Dev. Engineer

electrolyte
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Joined: Mon Sep 10, 2018 4:26 pm

Re: Questions about series 5000 & software

Post by electrolyte » Wed Sep 12, 2018 1:15 pm

Thanks for your help!

The measurements table only include the total measurements results of one type, not each individual measurement, right? I can not export 10000 particular frequency or any other measurements, but only the total calculated average, maximum, minimum, ...? If I want to have 10000 particular measurements I should be able to write some code using the api commands?

Can you explain the point about the trigger in more detail please? As far as I understand the time taken by an acquisition consists of the time for all samples to be collected and the time to set the scope up for another trigger event.
I understand that the time taken to collect all the samples depends on sampling speed and sample count settings. Does the time needed by the scope to trigger again after all previous data points (from the previous trigger event) have been acquired changes with time base also?

Is the possibility to capture 10000 waveform only a property of the PicoScope software?
You have mentioned that using API functions I have to segment the memory myself. So is it possible to segment the memory in more (but shorter) segments than 10000? Are here any limitations or can I segment the memory anyway I want?

Hitesh
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Re: Questions about series 5000 & software

Post by Hitesh » Thu Sep 13, 2018 3:41 pm

Hi electrolyte,

When PicoScope is running, the average, maximum and minimum values correspond to the values calculated since acquisition was started. If you load a data file, the above will be just for the data in the file.

If you are writing your own code using the API functions (please e-mail us for libraries), then you will need to develop your own algorithms or use a third party library such as Intel Integrated Performance Primitives or OpenCV.

When you start data collection e.g. by calling the ps5000aRunBlock() command there is an overhead to write the settings down to the device (tens of milliseconds) and there may also be some time to wait for a trigger to occur. There is also the time taken to transfer the data to the PC (until this is done after all the data has been collected). If you change timebase/collection time (thereby changing the sampling interval) then this will change the re-arm time as well.

When using the API functions, you can capture more than 10000 segments (this is a limitation of the PicoScope software). Use the ps5000aGetMaxSegments() function to find the maximum number of segments for your device, then call the ps5000aMemorySegments() function to set the number of segments. This latter function will provide the number of samples (shared between active channels) per segment.

Calling the ps5000aGetTimebase() function once you have set your channels can then be used to inform you of the maximum number of samples per channel.

I hope this helps.
Hitesh

Software Dev. Engineer

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