SL Series

import serial
magnaPower = serial.Serial(port='COM4', baudrate=19200)
magnaPower.write('*IDN?\n'.encode())
print magna_power.readline()
magnaPower.write('VOLT 0\n'.encode())
magnaPower.write('CURR 0\n'.encode())
magnaPower.write('OUTP:START\n'.encode())
magnaPower.write('VOLT 270\n'.encode())
currSetPoints = [50, 100, 150, 250]
for currSetPoint in currSetPoints:
    print 'Setting Current to %s A' % currSetPoint
    magnaPower.write('CURR {0}\n'.format(currSetPoint).encode())
    magnaPower.write('MEAS:VOLT?\n'.encode())
    print magnaPower.readline()
    time.sleep(20)
magnaPower.write('OUTP:STOP\n'.encode())
magnaPower.close()

magna_power = serial('COM4', 'BaudRate', 19200);
fopen(magnaPower);
fprintf(magnaPower,'*IDN?');
idn = fscanf(magnaPower);
fprintf(magnaPower,'VOLT 0');
fprintf(magnaPower,'CURR 0');
fprintf(magnaPower,'OUTP:START');
fprintf(magnaPower,'VOLT 270');
for currSetPoint in [50, 100, 150, 250]
    display('Setting Current to '+currSetPoint+' A');
    fprintf(magnaPower, 'CURR '+currSetPoint);
    fprintf(magnaPower,'MEAS:VOLT?');
    display(fscanf(magnaPower));
    pause(20);
end 

#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <windows.h>

int main()
{
    printf("Opening connection.\n");

    uint8_t recvBuffer[sizeof(uint8_t) * 256];
    memset(recvBuffer, 0, 256);

    // Choose the serial port name.  
    // COM ports higher than COM9 need the \\.\ prefix, which is written as
    // "\\\\.\\" in C because we need to escape the backslashes.
    const char* device = "\\\\.\\COM4";

    // Choose the baud rate (bits per second).  
    uint32_t baud_rate = 19200;

    HANDLE port = open_serial_port(device, baud_rate);
    if (port == INVALID_HANDLE_VALUE) { return 1; }

    char* scpiCmd = (char*)"*IDN?\n";
    size_t cmdLen = strlen(scpiCmd);
    int result = write_port(port, (uint8_t*)scpiCmd, cmdLen);
    if (result < 0)
        return -1;
   
    result = read_port(port, recvBuffer, 256);
    printf("Sent: %s\nReceived: %s\n", scpiCmd, recvBuffer);
   
    scpiCmd = (char*)"VOLT 0\n";
    cmdLen = strlen(scpiCmd);
    result = write_port(port, (uint8_t*)scpiCmd, cmdLen);
    if (result < 0)
        return -1;

    scpiCmd = (char*)"CURR 0\n";
    cmdLen = strlen(scpiCmd);
    result = write_port(port, (uint8_t*)scpiCmd, cmdLen);
    if (result < 0)
        return -1;

    scpiCmd = (char*)"OUTP:START\n";
    cmdLen = strlen(scpiCmd);
    result = write_port(port, (uint8_t*)scpiCmd, cmdLen);
    if (result < 0)
        return -1;

    scpiCmd = (char*)"VOLT 270\n";
    cmdLen = strlen(scpiCmd);
    result = write_port(port, (uint8_t*)scpiCmd, cmdLen);
    if (result < 0)
        return -1;

    char setPoints[4][5] = {"50", "100", "150", "200"};
    char setPointBuffer[40];
    scpiCmd = (char*)"MEAS:VOLT?\n";

    for (int i = 0; i < 4; i++)
    {
        sprintf(setPointBuffer, "CURR %s\n", setPoints[i]);
        printf("Setting current to %s A\n", setPoints[i]);
        cmdLen = strlen(setPointBuffer);
        result = write_port(port, (uint8_t*)setPointBuffer, cmdLen);
        if (result < 0)
            return -1;
        memset(recvBuffer, 0, 256);
        result = read_port(port, recvBuffer, 256);
        printf("Received: %s\n", recvBuffer);
        Sleep(20000);  // 20000ms = 20s
    }

    scpiCmd = (char*)"OUTP:STOP\n";
    cmdLen = strlen(scpiCmd);
    result = write_port(port, (uint8_t*)scpiCmd, cmdLen);
    if (result < 0)
        return -1;

    CloseHandle(port);

    printf("Connection closed.\n");
    return 0;
}

using System;
using System.IO.Ports;
using System.Threading;

namespace SerialCommunicationInCSharp
{
  public class Program
  {
    static bool _continue;
    static SerialPort serialPort;

    public static void Main(string[] args)
    {
      Thread readThread = new Thread(Read);

      Console.WriteLine("Opening connection.");

      // Create a new SerialPort object with default settings.
      serialPort = new SerialPort("COM4", 19200, Parity.None, 8, StopBits.One);

      // Set the read/write timeouts
      serialPort.ReadTimeout = 500;
      serialPort.WriteTimeout = 500;

      serialPort.Open();
      _continue = true;
      readThread.Start();

      Console.WriteLine("Sending: *IDN?");
      serialPort.WriteLine("*IDN?");

      serialPort.WriteLine("VOLT 0");
      serialPort.WriteLine("CURR 0");
      serialPort.WriteLine("OUTP:START");
      serialPort.WriteLine("VOLT 270");

      string[] currSetPoints = { "50", "100", "150", "250" };
ß
      for(int i = 0; i < currSetPoints.Length; i++)
      {
        serialPort.WriteLine(String.Format("'CURR {0}", currSetPoints[i]));
        serialPort.WriteLine("MEAS:VOLT?");
        Thread.Sleep(20000);
      }

      serialPort.WriteLine("OUTP:STOP");

      Console.WriteLine("Closing connection.");
      _continue = false;
      serialPort.Close();
      }

    public static void Read()
    {
      while (_continue)
      {
        try
        {
          string message = serialPort.ReadLine();
          Console.WriteLine("Received: " + message);
        }
        catch (TimeoutException) { }
      }
    }
  }
}