Basic FlexDCA Offline

The following diagram shows a FlexDCA Offline connection which is ideal for developing your scripts because it does not require an instrument. This script installs a simulated electrical module in DCA-X's slot 5, displays an eye diagram, and returns an eye height measurement. Notice that the address uses localhost instead of a DCA-X computer name.
Example Script

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basic-flex-offline.py
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""" Script on PC controls N1010A FlexDCA application. The script installs
a simulated module and, in Eye mode, returns NRZ eye height measurement.
"""

import pyvisa as visa  # import VISA library

visa_address = 'TCPIP0::localhost::hislip0,4880::INSTR'
CHANNEL = '5A'
TIMEOUT = 10000


def open_flexdca_connection(address):
    """ Opens visa connection to FlexFlexDCA. """
    print('Connecting to Flexdca ...')
    try:
        rm = visa.ResourceManager()
        connection = rm.open_resource(address)
        connection.timeout = 20000  # Set connection timeout to 20s
        connection.read_termination = '\n'
        connection.write_termination = '\n'
        inst_id = connection.query('*IDN?')
        print('\nFlexDCA connection established to:\n' + inst_id, flush=True)
        connection.write(':SYSTem:DEFault')
        connection.query('*OPC?')
    except (visa.VisaIOError, visa.InvalidSession):
        print('\nVISA ERROR: Cannot open instrument address.\n', flush=True)
        return None
    except Exception as other:
        print('\nVISA ERROR: Cannot connect to instrument:', other, flush=True)
        print('\n')
        return None
    return connection


def all_channels_off(FlexDCA):
    """ Turns all available channels off. """
    for slot in '12345678':
        for letter in 'ABCD':
            channel = slot + letter
            FlexDCA.write(':CHANnel' + channel + ':DISPlay OFF')


def install_simulated_module(FlexDCA, channel, model, signal='NRZ'):
    """ Simplified installation of a simulated FlexDCA module.
    model
        Type of simulated module. "DEM" is a dual-electrical module.
        "QEM" is a quad-electrical module. "DOM" is a dual-optical
        module. "QEM" is a electrical-optical module.
    signal
        Format of signal. NRZ or PAM4.
    """
    slot = channel[0]
    FlexDCA.write(':EMODules:SLOT' + slot + ':SELection ' + model)
    if signal in 'NRZ':
        FlexDCA.write(':SOURce' + channel + ':FORMat NRZ')
    else:
        FlexDCA.write(':SOURce' + channel + ':FORMat PAM4')
    FlexDCA.write(':SOURce' + channel + ':DRATe 9.95328E+9')
    FlexDCA.write(':SOURce' + channel + ':WTYPe DATA')
    FlexDCA.write(':SOURce' + channel + ':PLENgth 127')
    FlexDCA.write(':SOURce' + channel + ':AMPLitude 90E-3')
    FlexDCA.write(':SOURce' + channel + ':NOISe:RN 3.0E-6')
    FlexDCA.write(':SOURce' + channel + ':JITTer:RJ 4.0E-12')
    FlexDCA.write(':CHANnel' + channel + ':DISPlay ON')


def return_scalar(FlexDCA, query):
    """ Returns a FlexDCA scalar measurement result. """
    import time

    class ScalarMeasQuestionableException(Exception):
        """ A scalar measurement result is questionable. """
        pass

    class ScalarMeasTimeOutException(Exception):
        """ A scalar measurement has timed out. """
        pass

    timeout = FlexDCA.timeout / 1000  # convert ms to s
    query = query.strip('?')
    start_time = time.time()  # time in seconds
    while(True):
        time.sleep(0.2)
        status = FlexDCA.query(query + ':STATus?')
        if 'CORR' in status:  # valid measurement result
            return FlexDCA.query(query + '?')  # get measurement
        elif 'QUES' in status:  # questionable results
            s = query + '\nReason: ' + FlexDCA.query(query + ':STATus:REASon?')
            raise ScalarMeasQuestionableException(s)
        elif (int(time.time() - start_time)) > timeout:  # IO timout
            s = query + '\nReason: ' + FlexDCA.query(query + ':STATus:REASon?')
            raise ScalarMeasTimeOutException(s)


flexdca = open_flexdca_connection(visa_address)
flexdca.query(':SYSTem:DEFault;*OPC?')
all_channels_off(flexdca)
install_simulated_module(flexdca, '5A', 'DEM')
flexdca.write(':ACQuire:RUN')
flexdca.query(':SYSTem:MODE EYE;*OPC?')  # Switch to Eye/Mask mode
flexdca.query(':SYSTEM:AUToscale;*OPC?')
flexdca.write(':MEASure:EYE:EHEight')
meas = return_scalar(flexdca, ':MEASure:EYE:EHEight?')
print('Eye Height: ' + meas + 'V')

flexdca.write(':SYSTem:GTLocal')
flexdca.close()