Data collection with the PicoScope

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mrosema6
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Data collection with the PicoScope

Post by mrosema6 » Fri Jun 14, 2019 7:01 pm

Hi,

I'm new to PicoScope. I was trying to collect voltage and current ripple test data with my Picoscope and two strange things happened. One, when I saved the data as .psdata files, the plots showed up blank when I retrieved the data. However the data was still there because I was able to save a .csv file and see the data. Also is there a reason why the end of one frame won't match the beginning of the next frame? I getting sizeable differences in data between all my frames, especially for my current readings. But in between frames, I see no such jumps.

Martyn
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Re: Data collection with the PicoScope

Post by Martyn » Tue Jul 16, 2019 7:27 am

In general use the scope will collect a block of data, download this to the PC, then collect another. There will be gaps between the blocks where the scope is being rearmed for the next collection.

Can you send a psdata file with your data to support@picotech.com and the team will be able to explain what is happening with your specific settings.
Martyn
Technical Support Manager

PicoLilly
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Re: Data collection with the PicoScope

Post by PicoLilly » Thu Jul 18, 2019 7:11 pm

Could you please explain what defines a "block".
I have a 4425, so memory can hold 250MSamples.
I'm curious because, if I want to be sure I don't miss an event, how to configure the scope, so that I know that no data blocks have been transferred, (hence potential gaps), during my critical capture.

I presume a block has to be less than the memory allocated to capture these 250MSamples?

And one other point.
If it is a 12 bit resolution, then I presume each sample requires 12 bits to store it.
Do you class this as a 12 bit byte, or 1.5 8 bit bytes?

I'm just trying to calculate the megabytes memory required to contain 250MSamples.
Is it 250 megabytes ?

Thanks

Martyn
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Re: Data collection with the PicoScope

Post by Martyn » Fri Jul 19, 2019 11:59 am

The 250 MSamples is the internal memory of our device, you do not need to worry about bytes, as everything is worked in samples

We have two modes of capture

Streaming mode where data is sent as it is collected directly to the PC over the USB bus, the 250 MSamples of onboard memory is used as a FIFO buffer to prevent data loss.

Block mode where you capture single blocks of data to the on board memory and then transfer this to the PC once the block is complete

The biggest block you can collect is 250 MSamples , how much time this represents depends upon the chosen sampling rate.
Martyn
Technical Support Manager

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