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Trouble using ps5000aSetSigGenArbitrary with PicoScope 5244B

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Trouble using ps5000aSetSigGenArbitrary with PicoScope 5244B

Postby jaray » Fri Feb 20, 2015 8:27 pm

In order to verify I can am to use the AWG in my program, I used AWG drawer in PicoScope 6 to draw a one cycle square of 1024 samples. It starts high at 1 and goes to -1 halfway through the cycle.

Since the 5244B requires the signal to be from -32768 and +32767, I wrote this function to do this as seen below. I should note that I am doing this in C++ through the Qt framework.

Code: Select all
short *Acquisition5000::convertWaveFormToSamples(QVector<double>rawwaveform)
{
    short maxSample = 32767;
    QVector <short> tempvector(rawwaveform.size());

    for (int i = 0; i < rawwaveform.size(); i++)
    {
        tempvector[i] = rawwaveform.value(i)*maxSample;
    }
    return &tempvector[0];
}


rawwaveform was read in before this using the code below:

Code: Select all
void Acquisition5000::readInWaveFormFile(QVector<double> &Array)
{
    QFile file("C:/Users/Jason/Documents/Development/Qt/CrackDetection/outdata.csv");
    if (!file.open(QIODevice::ReadOnly))
    {
        qDebug() << "File Not Found in" << QDir::currentPath();
        return;
    }
    QTextStream in(&file);
    while (!in.atEnd())
    {
        QString line = in.readLine();
        Array.append(line.toDouble());
    }
    file.close();
}


At this point I have a short * variable that points to the starting position '&tempvector[0]' of the QVector <short>

From here I used an equation I found on the forums to calculate the deltaphase value as seen below:

Code: Select all
unsigned long  Acquisition5000::calculateDeltaFromFrequency(double frequency, long waveformSize)
{
    return (((frequency * waveformSize) / unitOpened_m.AWGFileSize) * AWG_PHASE_ACCUMULATOR * (1/AWG_DAC_FREQUENCY));
}

The value of waveformSize above is equal to the length of the waveform vector, in this case 1024.

So the actual function I use to call ps5000aSetSigGenArbitrary is seen below:
Code: Select all
void Acquisition5000::setSignalGenerator(double ddsFrequency)
{
    PICO_STATUS status;
    short *arbitraryWaveform = NULL;
    long waveformSize = (long)waveformvector.size(); //max of 49152
    unsigned long pkpk = 4000000;   
    long offset = 0;
    arbitraryWaveform = convertWaveFormToSamples(waveformvector);
    unsigned long deltaPhase = calculateDeltaFromFrequency(ddsFrequency,waveformSize);

    status = ps5000aSetSigGenArbitrary(   unitOpened_m.handle,
                    0,               // offset voltage
                    pkpk,            // PkToPk in microvolts. Max = 4V  +2v to -2V
                    deltaPhase,         // start delta
                    deltaPhase,         // stop delta
                    0,
                    0,
                    arbitraryWaveform,
                    waveformSize,
                    (PS5000A_SWEEP_TYPE)0,
                    (PS5000A_EXTRA_OPERATIONS)0,
                    PS5000A_SINGLE,
                    0,
                    0,
                    (PS5000A_SIGGEN_TRIG_TYPE) 0,
                    (PS5000A_SIGGEN_TRIG_SOURCE) 0,
                    0);
    systemArmed = true;
}


The result I get is just noise on the output of the signal generator, and sometimes not even that. I can't see anything that I am doing that would cause this to happen. Any ideas?
jaray
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Re: Trouble using ps5000aSetSigGenArbitrary with PicoScope 5

Postby Hitesh » Mon Feb 23, 2015 10:08 am

Hi jaray,

What is the value of deltaPhase once you have calculated it? Have you checked the values in the waveform array at the point of calling the function.

In the latest release of the SDK (10.5.2.1), the ps5000aApi.h header file contains the following function which can be used to calculate the phase value from the frequency:

Code: Select all
PREF0 PREF1 PICO_STATUS PREF2 PREF3(ps5000aSigGenFrequencyToPhase)
(
   int16_t   handle,
   double   frequency,
   PS5000A_INDEX_MODE      indexMode,
   uint32_t   bufferLength,
   uint32_t   * phase
);


The indexMode parameter should be the same as that passed to the ps5000aSetSigGenArbitrary function.

The bufferLength parameter is the number of samples.

What is the status code returned by the call to ps5000aSetSigGenArbitrary?

Regards,
Hitesh

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Re: Trouble using ps5000aSetSigGenArbitrary with PicoScope 5

Postby jaray » Mon Feb 23, 2015 2:17 pm

I didn't use that function because the version of the SDK I had, downloaded in early January, listed the function in the header file but did not seem to have it in the dll. I will download the latest SDK and try it out this morning.

As far as the AWG goes, I will make the necessary corrections and see what happens.
jaray
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Re: Trouble using ps5000aSetSigGenArbitrary with PicoScope 5

Postby jaray » Mon Feb 23, 2015 2:58 pm

So using the lib included in the new SDK build caused more problems than fixed.

I am now getting:
"acquisition5000.obj:-1: error: LNK2019: unresolved external symbol __imp__ps5000aGetTimebase2@24 referenced in function "private: void __thiscall Acquisition5000::blockDataHandler(char *,long)" (?blockDataHandler@Acquisition5000@@AAEXPADJ@Z)"

and still the original reason why I didn't using the included frequency to phase function

"acquisition5000.obj:-1: error: LNK2019: unresolved external symbol __imp__ps5000aSigGenFrequencyToPhase@24 referenced in function "public: void __thiscall Acquisition5000::setSignalGenerator(double)" (?setSignalGenerator@Acquisition5000@@QAEXN@Z)"

In other words those two functions are not part of this current builds .lib file.

I had this issue before as referenced here: topic13141.html

You sent me and updated lib file to my email which fixed the issues listed in the previous topic. However I hadn't tried ps5000aSigGenFrequencyToPhase at that point. If I use the lib file you sent me then I can use ps5000aGetTimebase2 but not ps5000aSigGenFrequencyToPhase. So it looks like in this latest build lib did not get updated once again. In fact, the build dates are the same as the SDK I downloaded early Janurary:
ps5000aApi - Created: Thursday, ‎September ‎11, ‎2014, ‏‎1:31:30 PM
ps5000a.dll - Created: Thursday, ‎December ‎11, ‎2014, ‏‎4:32:04 PM
ps5000a.lib - Created: Tuesday, ‎February ‎12, ‎2013, ‏‎9:52:18 AM

I don't know what was updated in the latest SDK build but it was not these.
jaray
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Re: Trouble using ps5000aSetSigGenArbitrary with PicoScope 5

Postby Hitesh » Mon Feb 23, 2015 3:50 pm

Hi jaray,

I've just sent you a link to download the 32-bit lib and dll files via your support ticket.

The API header file should be fine.

Regards,

Hitesh
Hitesh

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Re: Trouble using ps5000aSetSigGenArbitrary with PicoScope 5

Postby jaray » Mon Feb 23, 2015 3:52 pm

Thanks, Hitesh, I just received the email and will try these out momentarily. Currently playing around with reading in the csv file. I checked the contents of the array I was passing, and things were not quite right.
jaray
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Re: Trouble using ps5000aSetSigGenArbitrary with PicoScope 5

Postby jaray » Mon Feb 23, 2015 7:34 pm

I responded in the email, but I will do it here also in case anyone else runs into the same issues.

Upon using the new dll and lib you sent to my email, I received this email upon compiling:
*** A stack buffer overrun occurred in C:\Users\Jason\Documents\Development\Qt\build-CrackDetection-Desktop_Qt_5_4_0_MSVC2013_32bit-Debug\debug\CrackDetection.exe:

This is usually the result of a memory copy to a local buffer or structure where the size is not properly calculated/checked.
If this bug ends up in the shipping product, it could be a severe security hole.
The stack trace should show the guilty function (the function directly above __report_gsfailure).
*** enter .exr 774BA9A8 for the exception record
*** then kb to get the faulting stack


I have not had this problem with any other versions of the dll or lib.

In other news, using the old files I have the information you requested.

Using my function to calculate deltaPhase based on the equations in the original post, I get a value of 4294963874 when the input frequency is
unsigned long pkpk = 4000000;
and the waveform length is
long waveformSize = (long)waveformvector.size(); or in my case for this waveform 1024.

When I call the arbitrary function by saying:
Code: Select all
status = ps5000aSetSigGenArbitrary(   unitOpened_m.handle,
                        0,               // offset voltage
                        pkpk,            // PkToPk in microvolts. Max = 4V  +2v to -2V
                        deltaPhase,         // start delta
                        deltaPhase,         // stop delta
                        0,
                        0,
                        arbitraryWaveform,
                        waveformSize,
                        (PS5000A_SWEEP_TYPE)0,
                        (PS5000A_EXTRA_OPERATIONS)0,
                        PS5000A_SINGLE,
                        0,
                        0,
                        (PS5000A_SIGGEN_TRIG_TYPE) 0,
                        (PS5000A_SIGGEN_TRIG_SOURCE) 0,
                        0);

I get a status return of 0 or PICO_OK.

All I need this to do right now is to output the waveform continuously.
jaray
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Re: Trouble using ps5000aSetSigGenArbitrary with PicoScope 5

Postby jaray » Mon Feb 23, 2015 8:36 pm

I was able to get the function to work by creating a signal that had the max number of samples. I am going to investigate further into varying sample sizes to see how it changes.
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Re: Trouble using ps5000aSetSigGenArbitrary with PicoScope 5

Postby Hitesh » Wed Feb 25, 2015 1:47 pm

Hi jaray,

Using my function to calculate deltaPhase based on the equations in the original post, I get a value of 4294963874 when the input frequency is
unsigned long pkpk = 4000000;


The value 4294963874 is close to 2^32 which doesn't seem right. What is the frequency that you are looking to output as the peak to peak voltage was given above?

Regards,
Hitesh

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Re: Trouble using ps5000aSetSigGenArbitrary with PicoScope 5

Postby jaray » Wed Feb 25, 2015 3:09 pm

So I set up several debug statements to watch variables as I need them. Turns out I had awgBufferSize in my UNIT struct defined as a short instead of an unsigned short so using PS5X44A_MAX_SIG_GEN_BUFFER_SIZE caused the variable to turn negative because it is larger than 32767. I found an example on the forums of opening and closing the PicoScope 5000 series using C++ somewhere on the forums that I based the beginning of my project on that defined the awgBufferSize like this instead of an unsigned variable. I've verified my output and all is well now that I have adjusted the variable type.

Thanks for the help! I am sure I will be posting about other questions in the near future as I start working on data collection.

-Jason
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