programming using C of the V+ V- programmable power source in AD2

[ssm]

Dear Help,

I am trying to use the programmable power supply as an offset for a signal. Using the offset with the WaveGen is not working because it is taking a long time to reach the target offset I need, so I am just using a dc power source instead.

Can I use the V+ and ground to use as a power source in the circuit? I only need the positive voltage, up to 3.7V, is that possible?

I can see this example in the SDK set (if you can point me to more examples I will be grateful):

// set up analog IO channel nodes

    // enable positive supply

    FDwfAnalogIOChannelNodeSet(hdwf, 0, 0, 1);

    // enable negative supply

    FDwfAnalogIOChannelNodeSet(hdwf, 1, 0, 1);

    // master enable

    FDwfAnalogIOEnableSet(hdwf, true);

    printf("Total supply power and load percentage:\n");

    for(int i = 0; i < 60; i++){

        // wait 1 second between readings

        Wait(1);

        // fetch analogIO status from device

        FDwfAnalogIOStatus(hdwf);

        // supply monitor

        FDwfAnalogIOChannelNodeStatus(hdwf, 3, 0, &vSupply);

        FDwfAnalogIOChannelNodeStatus(hdwf, 3, 1, &aSupply);

        wSupply = vSupply * aSupply;

        prcSupply = 100 * (aSupply / 0.2);

        printf("%.3lf W \t%i%%\n", wSupply, prcSupply);

            // in case of over-current condition the supplies are disabled

        FDwfAnalogIOEnableStatus(hdwf, &fOn);

        if(!fOn){

            // re-enable supplies

            FDwfAnalogIOEnableSet(hdwf, false);

            FDwfAnalogIOEnableSet(hdwf, true);

        }

    }

Edited November 24, 2022 by ssm

[attila]

Hi @ssm

I don't know exactly your experiment details but you can configure the AWG offset, wait 100ms then generate signals... or you could use custom waveforms which does not need analog offset.

The supplies have about 10ms, the AWG offsets 15ms and the Scope offset 0.5sec settle time. Due to this, after (the first) connection to the device or adjusting Scope offset or range you should wait at least 0.5-2sec.

 

Edited November 24, 2022 by attila

[ssm]

thank you @attila

well my experiment is that I am using a constructed custom signal, this signal is run once and the result is collected during this run,

the duration of this signal is short (I have different cases, some cases is in the us) I need to offset this signal, i tried to embed the offset in that signal it did not work, I tried to use the offset from the board, it did not work, so that is why I am using the PPS V+, I can switch it ON and wait before I start my experiment

ssm

[ssm]

I have question regarding the connections, can I connect the WaveGen and V+/V- in series? in other words, if the ground black wire of the WaveGen global ground or ground used for the WaveGen only? if I connected V+ to GND black wire will it short the V+?

please see attached image,

 

[attila]

Hi @ssm

The device has one, common GND which is connected to the computer through the USB cable.
Connecting V+ to GND will short it and the supplies (V+/-) will shut down.

You could for instance use V- as virtual ground for the circuit under test, so with V+/- +/-5V you could supply your circuit with 10Vpk2pk. In this case the W1 0V will be +5V for the circuit, -5V will be 0V, +5 will be +10V ...

[ssm]

thank you @attila for the great help,

[ssm]

Hi @attila

I have a question regarding this command line:

FDwfAnalogInChannelRangeSet(hdwf, -1, 8);

if I have my range to be between 3.5 V and 4 V, what value should I put here, 8V? will the bigger value, i.e. 8V instead of 4 V, reduce the precision of the value read by the scope?

thank you for the help

ssm

[attila]

Hi @ssm

The AD2 has two range steps 5/50Vpk2pk so with 8V it would use 50V range with lower resolution.

FDwfAnalogInChannelRangeSet(hdwf, -1, 0.5);
FDwfAnalogInChannelOffsetSet(hdwf, -1, 3.75); 3.75V +/- 0.5V/2 = 3.5V...4V

To be in low range with AD2 the range should be set up to 5V and the offset +/- range/2 should be between +/-8V and trigger if specified for the channel also in this range,
so for 5.5V...0.5V (3V+/- 5V/2) you could use:
FDwfAnalogInChannelRangeSet(hdwf, -1, 5.0);
FDwfAnalogInChannelOffsetSet(hdwf, -1, 3.0); -5.5...5.5

[ssm]

thank you @attila for the great help,

I have a sine wave signal with an offset, the signal pk2pk is +/- 0.1V and the offset is 5 V

I am using the following code:

FDwfAnalogInChannelRangeSet(hdwf, 0, 50.0);
FDwfAnalogInChannelOffsetSet(hdwf, 0, 5.0);  

but I am getting the signal to be cropped at around the 5V

the attached image shows the output signal

[attila]

Hi @ssm

Are you setting 50V range before calling FDwfAnalogInConfigure ?

[ssm]

yes, that is correct, note that the signal is 5+/-0.1 V, since it is greater than 5v I put the range to be 50V, otherwise I am not using the full range of 50V

additional note, the following is working fine:

 the signal pk2pk is +/- 0.1V and the offset is 4.8 V

I am using the following code:

FDwfAnalogInChannelRangeSet(hdwf, 0, 0.2);
FDwfAnalogInChannelOffsetSet(hdwf, 0, 4.8);  

 

Edited January 4, 2023 by ssm

[attila]

Hi @ssm

The AD2 has 2 ranges 5V and 50V pk2pk.
If it is shown correctly with low range (high gain) <= 5V range then it also should fit in 50V range with lower resolution.
After adjusting the range, before starting a capture and offset, use some sleep/wait for the offsets to settle.

[ssm]

thank you @attilafor your reply,

should I do it like that?

FDwfAnalogInChannelRangeSet(hdwf, 0, 50.0);

wait(2)
FDwfAnalogInChannelOffsetSet(hdwf, 0, 5.0);  

btw I am waiting 2 sec before configuration and after configuration 

 

[attila]

Hi @ssm

Like it is in the examples:

[ssm]

thank you for the help, it is working now

I added Wait(2) after the two line:

FDwfAnalogInChannelRangeSet(hdwf, 0, 50.0);
FDwfAnalogInChannelOffsetSet(hdwf, 0, 5.0);  

wait(2)

Edited January 5, 2023 by ssm