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Issues with using picoscope 6 tools in labview

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Issues with using picoscope 6 tools in labview

Postby Justiceb » Tue Sep 13, 2016 4:25 pm

Hi, I am running a program in labview which reads and analyses a signal from a picoscope 6402D. In order for my program to work, there are some preliminary adjustments I need to make to the signal. I am able to condition the signal to what I want it to look like in the picoscope 6 software, but the toolset in labview is missing some of the functions I need. Is there a way to import the settings or signal I have in the picoscope software over to labview? Thanks
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Re: Issues with using picoscope 6 tools in labview

Postby Hitesh » Wed Sep 14, 2016 12:54 pm

Hi Justiceb,

There is no facility to take the settings from the PicoScope 6 software and directly apply them via the driver API functions.

I would suggest looking at the settings that you have in the PicoScope 6 software, i.e.

  • channel settings (range, DC coupling and offset)
  • number of samples
  • trigger settings
  • sampling interval (via the Properties pane)
You can then map these to the appropriate settings in the LabVIEW example, referring to the Programmer's Guide as required.

If you require further assistance with this, please send the PicoScope settings file (.pssettings) or a data file showing the actual signal and we can advise further.

Regards,
Hitesh

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Re: Issues with using picoscope 6 tools in labview

Postby Justiceb » Wed Sep 14, 2016 6:12 pm

Thank you, I will look through the manual and if I'm still stuck I will send those to you. One question though, I see that there was an updated SDK released in 2015, I am using an earlier ps6000.dll driver file. I've downloaded the new sdk but cannot find the "lib" subdirectory in my SDK install. Where should I look to find that? Thanks!
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Re: Issues with using picoscope 6 tools in labview

Postby Hitesh » Thu Sep 15, 2016 7:32 am

Hi Justiceb,

Please refer to this post for information on the installation location.

Regards,
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Re: Issues with using picoscope 6 tools in labview

Postby Justiceb » Mon Sep 26, 2016 7:11 pm

Upgrading the driver helped the signal considerably, but it still is not as clear in labview as I can get it in the picoscope software. Is it possible to use the bit resolution or low pass filter options from the picoscope software in labview or perhaps tweak values in the driver?
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Re: Issues with using picoscope 6 tools in labview

Postby Hitesh » Tue Sep 27, 2016 9:46 am

Hi JusticeB,

The resolution enhancement and low pass filter are implemented using software - there are descriptions of these in the PicoScope 6 User's Guide.

There is a bandwidth limiter available via the ps6000SetChannel() function that you can try.

It might be helpful to see your PicoScope 6 settings and what you have set in your LabVIEW code to match that.

Are you converting the raw ADC count values to volts/millvolts?

Regards,
Hitesh

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Re: Issues with using picoscope 6 tools in labview

Postby Justiceb » Wed Sep 28, 2016 4:17 pm

here are the settings for the oscilloscope software:
Settings9_28.pssettings
Picoscope settings
(3.19 KiB) Downloaded 12 times

here is my labview code:
Ultrasonic Thickness Measurement.vi
Labview code
(808.02 KiB) Downloaded 17 times
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Re: Issues with using picoscope 6 tools in labview

Postby Justiceb » Wed Sep 28, 2016 4:21 pm

The labview code is reading a signal from a ultrasonic transducer and measuring the peak to peak time difference between the sent and reflected waves to measure distance
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Re: Issues with using picoscope 6 tools in labview

Postby Hitesh » Thu Sep 29, 2016 9:49 am

Hi JusticeB,

I've checked your settings and noticed a few differences as follows:

Channel settings:

  • The channel range is set to +/- 100 mV in the PicoScope 6 software

Acquisition Settings:

  • Your settings file shows a pre-trigger setting of 20% and 100,000 samples so you should set your pre-trigger samples to 20,000 and post-trigger to 80,000 to match this.
  • Timebase should be set to 0 if you need a sampling interval of 200 ps.
  • Enable the Four Channel Device option.

Trigger settings:

  • The threshold can be changed to 0 if you only need a 0 V trigger threshold (note that this is in ADC counts).

The resolution enhancement is a software feature so this is something you will need to implement. You could try using the Average Down-Sample mode with a ratio greater than 1 and see what effect this has.

Hope this helps,
Hitesh

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Re: Issues with using picoscope 6 tools in labview

Postby Justiceb » Fri Sep 30, 2016 4:06 pm

i will give that a try, thank you!
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Re: Issues with using picoscope 6 tools in labview

Postby Justiceb » Fri Oct 07, 2016 5:29 pm

Adjusting those settings did give me a more clear signal, but I am still wanting to filter it some more. I am attempting to implement the SetChannel() function as you recommended. So far I have been able to call the function in labview, but I do not understand how to set the parameter types outlined in the programming guide. I have attached a clipping of the window for more clarification. Thanks for your help,
Justice
Attachments
PS6000SetChannelParameters.JPG
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Re: Issues with using picoscope 6 tools in labview

Postby Hitesh » Mon Oct 10, 2016 10:12 am

H Justiceb,

The ps6000SetChannel() function is used in the PS6000 Settings sub-vi so you should be able to use this or copy the Call Library Function node out.

Comparing the definition that you have with the actual definition:

Code: Select all
PICO_STATUS ps6000SetChannel
(
int16_t handle,
PS6000_CHANNEL channel,
int16_t enabled,
PS6000_COUPLING type,
PS6000_RANGE range,
float analogueOffset,
PS6000_BANDWIDTH_LIMITER bandwidth
)

The handle parameter should be a signed 16-bit integer and any enumeration values such as PS6000_COUPLING should be a signed or unsigned 32-bit integer. The analogue offset should be a single precision floating point number.

Regards,
Hitesh

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Re: Issues with using picoscope 6 tools in labview

Postby Justiceb » Mon Oct 17, 2016 4:25 pm

Hi, I have the function set up, but am having some problems with the inputs. The type and bandwidth settings I am not sure about, I have tried numerical control but I get an error from labview. For bandwidth I'm guessing I need to put the value I want in in hertz? Also, I located the function immediately after the ps6000getunitinfo function and immediately before the picostatus function. Is this correct? Thanks!
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Re: Issues with using picoscope 6 tools in labview

Postby Hitesh » Tue Oct 18, 2016 8:25 am

Hi Justiceb,

The function definition should be as shown in the example below taken from the PicoScope6000Settings.vi which you can find in the PicoScope6000.llb file referenced by the examples in the SDK.

PS6000SetChannel_CFLB.PNG
Call Library Function Node for ps6000SetChannel function

I would suggest using the code from the llb file as it uses clusters to group the controls for a channel and pass them through to the Call Library Function node.

In terms of where to place the function call, you can do this after the call to ps6000GetUnitInfo() but after the Pico Status sub-vi which corresponds to the ps6000GetUnitInfo(). Each call to a function should have its own Pico Status sub-vi afterwards as that is used to handle any status codes returned from the driver which might indicate an error or warning.

Regards,
Hitesh

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