2.3.6.2.3. Interactive voltage setting on a slow analog output

2.3.6.2.3.1. Description

This example shows how to set analog voltage on slow analog Red Pitaya outputs using a MATLAB slider. Slow analog outputs on the Red Pitaya are in the range of 0 to 1.8 Volts.

2.3.6.2.3.2. Required hardware

• Red Pitaya device

• Voltmeter

Wiring example for STEMlab 125-14 & STEMlab 125-10:

2.3.6.2.3.3. Circuit

2.3.6.2.3.4. SCPI Code Examples

2.3.6.2.3.4.1. Code - MATLAB®

The code is written in MATLAB. In the code, we use SCPI commands and TCP client communication. Copy the code from below into the MATLAB editor, save the project, and hit the “Run” button.

function sliderDemo

    f = figure(1);
    global p;


    %// initialize the slider
    h = uicontrol(...
        'parent'  , f,...
        'units'   , 'normalized',...     %// pixels settings
        'style'   , 'slider',...
        'position', [0.05 0.05 0.9 0.05],...
        'min'     , 1,...                %// Make the "value" between min ...
        'max'     , 100,...              %// max 10, with initial value
        'value'   , 10,...               %// as set.
        'callback', @sliderCallback);    %// This is called when using the
                                        %// arrows
                                        %// and/or when clicking the slider bar

    hLstn = addlistener(h,'ContinuousValueChange',@sliderCallback);
    %// (variable appears unused, but not assigning it to anything means that
    %// the listener is stored in the 'ans' variable. If "ans" is overwritten,
    %// the listener goes out of scope and is thus destroyed, and thus, it no
    %// longer works.

    function  sliderCallback(~,~)

        p =(get(h,'value'))

        %% Define Red Pitaya as TCP/IP object

        IP = '192.168.178.108';           % Input IP of your Red Pitaya...
        port = 5000;
        RP = tcpclient(IP, port);

        %% Open connection with your Red Pitaya

        RP.ByteOrder = "big-endian";
        configureTerminator(RP,"CR/LF");

        %% Set your output voltage value and pin

        out_voltage = num2str((1.8/100)*p)      % From 0 - 1.8 volts
        out_num = '2';                          % Analog outputs 0,1,2,3
        %% Set your SCPI command with strcat function

        scpi_command = strcat('ANALOG:PIN AOUT',out_num,',',out_voltage);

        %% Send SCPI command to Red Pitaya

        writeline(RP, scpi_command);

        %% Close connection with Red Pitaya

        clear RP;
    end
end

2.3.6.2.3.4.2. Code - LabVIEW

• Download Example

2.3.6.2.3.5. API Code Examples

Note

The API code examples don’t require the use of the SCPI server. Instead, the code should be compiled and executed on the Red Pitaya itself (inside Linux OS). Instructions on how to compile the code and other useful information are here.

2.3.6.2.3.5.1. Code - Python API

#!/usr/bin/python3
import time
import rp

analog_out = [rp.RP_AOUT0, rp.RP_AOUT1, rp.RP_AOUT2, rp.RP_AOUT3]
out_voltage = [1.0, 1.0, 1.0, 1.0]
is_float = True

# Initialize the interface
rp.rp_Init()

# Reset analog pins
rp.rp_ApinReset()

#####! Choose one of two methods, comment the other !#####
while 1:
    out_voltage = input("Enter Values of 4 analog inputs: ").split()     # Split input

    for i in range(4):
        try:
            # Try to convert input to float
            float(out_voltage[i])
        except ValueError:
            is_float = False      # set flag to false if the conversion fails
        else:
            is_float = True
            out_voltage[i] = float(out_voltage[i])  # convert input string to float

            if not 0 <= out_voltage[i] <= 1.8:   # Check for value out of bounds
                out_voltage[i] = 1.0

    if is_float:              # If input is float
        for i in range(4):
            #! METHOD 1: Configuring specific Analog pin
            rp.rp_ApinSetValue(analog_out[i], out_voltage[i])
            print (f"Set voltage on AO[{i}] to {out_voltage[i]} V")

            #! METHOD 2: Configure just slow Analog outputs
            rp.rp_AOpinSetValue(i, out_voltage[i])
            print (f"Set voltage on AO[{i}] to {out_voltage[i]} V")
    else:
        print("Invalid input")
    time.sleep(0.2)

# Release resources
rp.rp_Release()