Poll for Sweep Complete

import time

import pyvisa as visa

def write_with_stb_polling(session,command,timeout):

    # Enable operation complete status register

    session.write("*ESE 1")

    # Clear the existing status state

    session.query("*ESR?")

    # Send asynchronous command

    session.write(command)

    # *OPC indicates that we want to be notified when the asyn command is completed

    # Note that we are NOT using the query form, so this does not block

    session.write("*OPC")

    # Check if the asyn operation has completed by checking bit 5 (32)

    isDone = session.read_stb() & 32

    end_time = time.time() + timeout

    while (not isDone and time.time() < end_time):

        time.sleep(0.1) # sleep for 100 ms to avoid working the CPU

        isDone = session.read_stb() & 32

    # If still not done, then it is because the timeout was hit

    # Report it as an exception

    if (not isDone):

        raise Exception(f"Timeout exceeded ({timeout}s) with {command}")

# Change this variable to the address of your instrument

# or leave this alone when using the simulator

VISA_ADDRESS = 'TCPIP0::localhost::inst0::INSTR'

# Create a connection (session) to the instrument

resourceManager = visa.ResourceManager()

session = resourceManager.open_resource(VISA_ADDRESS)

# Command to preset the instrument and deletes the default trace, measurement, and window

session.write("SYST:FPR")

# Create and turn on window 1

session.write("DISP:WIND1:STAT ON")

# Create the measurement

session.write("CALC1:MEAS1:DEF 'S11'")

# Displays measurement 1 in window 1 and assigns the next available trace number to the measurement

session.write("DISP:MEAS1:FEED 1")

# Set the channel into hold mode

session.write("SENS:SWE:MODE HOLD")

# Set sweep time to 2 seconds to simulate a slow sweep

session.write("SENS:SWE:TIME 2")

print("Start Sweep")

timeoutForCommand = 10 # 10 seconds timeout

write_with_stb_polling(session,"SENS:SWE:MODE SING",timeoutForCommand)

print("Stop Sweep")