SCPI Commands

import pyvisa

rm = pyvisa.ResourceManager()
instrument = rm.open_resource('TCPIP::192.168.1.100::INSTR')

# Identity and system info
idn = instrument.query('*IDN?')  # IEEE 488.2 identification
errors = instrument.query('SYST:ERR?')  # Check for errors
instrument.write('*RST')  # Reset to default state
instrument.write('*CLS')  # Clear status registers

# DC voltage measurement
voltage = float(instrument.query('MEAS:VOLT:DC?'))

# AC voltage with range
instrument.write('MEAS:VOLT:AC:RANG 10')
ac_voltage = float(instrument.query('MEAS:VOLT:AC?'))

# Current measurement
current = float(instrument.query('MEAS:CURR:DC?'))

# Resistance measurement  
resistance = float(instrument.query('MEAS:RES?'))

# Set measurement range
instrument.write('VOLT:DC:RANG 10')  # 10V range
instrument.write('CURR:DC:RANG 0.1')  # 100mA range

# Set resolution/integration time
instrument.write('VOLT:DC:NPLC 10')  # 10 power line cycles

# Enable/disable auto-ranging
instrument.write('VOLT:DC:RANG:AUTO ON')

def check_errors(instrument):
    """Check and clear any SCPI errors"""
    errors = []
    while True:
        error = instrument.query('SYST:ERR?')
        if error.startswith('0'):  # No error
            break
        errors.append(error.strip())
    return errors

# Usage
errors = check_errors(instrument)
if errors:
    print(f"SCPI Errors: {errors}")

# Wait for operation to complete
instrument.write('*OPC?')  # Operation complete query
result = instrument.read()  # Returns '1' when done

# Using service request
instrument.write('*ESE 1')  # Enable operation complete
instrument.write('*SRE 32')  # Enable standard event
instrument.write('INIT')  # Start measurement
instrument.wait_for_srq()  # Wait for service request

# Binary data transfer (faster than ASCII)
instrument.write('FORM:DATA REAL,32')  # 32-bit floats
instrument.write('TRAC:DATA?')
data = instrument.read_binary_values('f')  # Read as floats

# Multiple measurements
instrument.write('SAMP:COUN 1000')  # 1000 samples
measurements = instrument.query_binary_values('READ?', datatype='f')

# Keysight 34401A/34411A style commands
instrument.write('CONF:VOLT:DC 10,0.0001')  # Range, resolution
instrument.write('TRIG:SOUR IMM')  # Immediate trigger
measurement = float(instrument.query('READ?'))

# Statistics
instrument.write('CALC:FUNC "AVER"')  # Average function
instrument.write('CALC:STAT ON')  # Enable statistics
average = float(instrument.query('CALC:AVER?'))

# Acquisition setup
instrument.write('ACQ:MODE RTIME')  # Real-time mode
instrument.write('ACQ:SRAT 1E9')   # 1 GSa/s sample rate

# Channel configuration
instrument.write('CHAN1:SCAL 0.1')  # 100mV/div
instrument.write('CHAN1:OFFS 0')    # 0V offset

# Trigger setup
instrument.write('TRIG:SOUR CHAN1')  # Trigger source
instrument.write('TRIG:LEV 0.5')     # 0.5V trigger level

# Data acquisition
waveform = instrument.query_binary_values('CURV?', datatype='h')

# Basic sine wave
instrument.write('SOUR:FUNC SIN')     # Sine wave
instrument.write('SOUR:FREQ 1000')    # 1 kHz
instrument.write('SOUR:VOLT 1')       # 1V amplitude
instrument.write('OUTP ON')           # Enable output

# Modulation
instrument.write('SOUR:AM:STAT ON')   # Enable AM
instrument.write('SOUR:AM:DEPT 50')   # 50% modulation depth
instrument.write('SOUR:AM:FREQ 100')  # 100 Hz modulation

# Integer values
instrument.write('SYST:BEEP:FREQ 1000')  # Integer frequency

# Real (floating point) values  
instrument.write('SOUR:VOLT:AMPL 2.5')   # Real amplitude

# Exponential notation
instrument.write('SOUR:FREQ 1.5E3')      # 1500 Hz

# Various boolean representations
instrument.write('OUTP ON')    # ON/OFF
instrument.write('OUTP 1')     # 1/0  
instrument.write('OUTP TRUE')  # TRUE/FALSE

# Quoted strings for special characters
instrument.write('DISP:TEXT "Hello World"')

# Unquoted for simple strings
instrument.write('SOUR:FUNC SIN')

class SCPIInstrument:
    def __init__(self, resource_string):
        self.rm = pyvisa.ResourceManager()
        self.instrument = self.rm.open_resource(resource_string)
        
    def write_with_error_check(self, command):
        """Write command and check for errors"""
        self.instrument.write(command)
        errors = self.check_errors()
        if errors:
            raise Exception(f"SCPI Error after '{command}': {errors}")
    
    def query_with_error_check(self, command):
        """Query with error checking"""
        result = self.instrument.query(command)
        errors = self.check_errors()  
        if errors:
            raise Exception(f"SCPI Error after '{command}': {errors}")
        return result
        
    def check_errors(self):
        """Check instrument error queue"""
        errors = []
        try:
            while True:
                error_response = self.instrument.query('SYST:ERR?')
                if error_response.startswith('0'):
                    break
                errors.append(error_response.strip())
        except:
            pass  # Some instruments don't support SYST:ERR?
        return errors

# Usage
instr = SCPIInstrument('TCPIP::192.168.1.100::INSTR')
try:
    instr.write_with_error_check('CONF:VOLT:DC')
    voltage = instr.query_with_error_check('READ?')
except Exception as e:
    print(f"SCPI Error: {e}")

# Set appropriate timeouts
instrument.timeout = 10000  # 10 seconds for slow measurements

# Context manager for temporary timeout
from contextlib import contextmanager

@contextmanager
def temporary_timeout(instrument, timeout_ms):
    old_timeout = instrument.timeout
    instrument.timeout = timeout_ms
    try:
        yield instrument
    finally:
        instrument.timeout = old_timeout

# Usage for slow measurement
with temporary_timeout(instrument, 60000):  # 60 seconds
    long_measurement = instrument.query('MEAS:VOLT:DC?')

# Bad: Multiple separate commands
instrument.write('VOLT:DC:RANG 10')
instrument.write('VOLT:DC:NPLC 1')  
instrument.write('TRIG:SOUR IMM')
instrument.write('SAMP:COUN 100')

# Better: Combine when possible
setup_commands = [
    'VOLT:DC:RANG 10',
    'VOLT:DC:NPLC 1', 
    'TRIG:SOUR IMM',
    'SAMP:COUN 100'
]
for cmd in setup_commands:
    instrument.write(cmd)

# Best: Use semicolon separator if supported
instrument.write('VOLT:DC:RANG 10;NPLC 1;TRIG:SOUR IMM;SAMP:COUN 100')

# ASCII transfer (slower, human readable)
data_ascii = instrument.query('TRAC:DATA? TRAC1')
values = [float(x) for x in data_ascii.split(',')]

# Binary transfer (faster, less bandwidth)
instrument.write('FORM:DATA REAL,32')
data_binary = instrument.query_binary_values('TRAC:DATA? TRAC1', datatype='f')

*CLS                    # Clear status
*ESE <value>           # Standard event status enable  
*ESR?                  # Standard event status register
*IDN?                  # Identification query
*OPC                   # Operation complete
*OPC?                  # Operation complete query
*RST                   # Reset
*SRE <value>           # Service request enable
*STB?                  # Status byte query
*TST?                  # Self test query
*WAI                   # Wait

SYSTEM
  :ERRor?              # Error queue query
  :VERSion?            # SCPI version query
  :BEEPer              
    :FREQuency <freq>  # Beeper frequency
    :STATe <bool>      # Beeper on/off

MEASure
  :VOLTage
    :DC? [@<list>]     # DC voltage measurement
    :AC? [@<list>]     # AC voltage measurement
  :CURRent
    :DC? [@<list>]     # DC current measurement  
    :AC? [@<list>]     # AC current measurement
  :RESistance? [@<list>] # Resistance measurement
  :FREQuency? [@<list>]  # Frequency measurement

CONFigure
  :VOLTage
    :DC [<range>[,<resolution>]] [@<list>]
    :AC [<range>[,<resolution>]] [@<list>]
  :CURRent
    :DC [<range>[,<resolution>]] [@<list>]
    :AC [<range>[,<resolution>]] [@<list>]

TRIGger
  :SOURce <source>     # Trigger source
  :DELay <seconds>     # Trigger delay
  :COUNt <count>       # Trigger count

SAMPle
  :COUNt <count>       # Sample count

READ?                  # Initiate and fetch measurement
INITiate              # Initiate trigger system  
FETCh?                # Fetch last measurement