Control and Measurement Toolkit
Providing generic instrument drivers, instrument emulators for testing and and utilities for instrumentation applications. Inspired by QCoDeS, Lantz, Slave, FluidLab.
Install from GitHub using pip
pip install https://github.com/hephy-dd/comet/archive/refs/tags/v1.2.2.tar.gzGeneric instrument drivers use a PyVISA compatible resource to communicate with.
import pyvisa
from comet.driver.keithley import K2470
rm = pyvisa.ResourceManager("@py")
with rm.open_resource("TCPIP::0.0.0.0::11001::SOCKET") as res:
smu = K2470(res)
print(smu.identify())
smu.reset()
smu.function = smu.FUNCTION_VOLTAGE
smu.current_compliance = 1e-6
smu.output = smu.OUTPUT_ON
smu.voltage_level = 5.0
reading = smu.measure_current()
print(reading)
smu.voltage_level = 0.0
smu.output = smu.OUTPUT_OFFLoading driver by module name using driver factory.
from comet.driver import driver_factory
rm = pyvisa.ResourceManager("@py")
with rm.open_resource("TCPIP::0.0.0.0::11001::SOCKET") as res:
smu = driver_factory("keithley.k2410")(res)Switching between generic drivers.
from comet.driver import driver_factory
smu_drivers = {
"Keithley2410": driver_factory("keithley.k2410"),
"Keithley2470": driver_factory("keithley.k2470"),
"Keithley2657A": driver_factory("keithley.k2657a"),
}
driver_name = "Keithley2470"
rm = pyvisa.ResourceManager("@py")
with rm.open_resource("TCPIP::0.0.0.0::11001::SOCKET") as res:
smu = smu_drivers.get(driver_name)(res)See package comet.driver for available instrument drivers.
Estimate remaining time for loop operations using class Estimate.
Call method advance to proceed to the next iteration and update average and
remaining time calculation.
from comet.estimate import Estimate
n = 42
e = Estimate(n) # start stopwatch
for i in range(n):
...
e.advance() # stop time since last step
print("passed:", e.passed)
print("remaining time:", e.remaining)
print("elapsed time:", e.elapsed)
print("average time:", e.average)Test if standard deviation / mean < threshold using function std_mean_filter.
from comet.filters import std_mean_filter
if std_mean_filter(readings, threshold=0.005):
...Voltage ramps using LinearRange generator class.
from comet.functions import LinearRange
for voltage in LinearRange(-10, +10, 0.25):
...Bind typed and bounded parameters to classes inheriting from class
ParameterBase.
from comet.parameter import ParameterBase, Parameter
class Measurement(ParameterBase):
voltage_level = Parameter(unit="V", minimum=-1000, maximum=1000)
current_compliance = Parameter(default="25 uA", unit="A", minimum=0, maximum="10 mA")
terminal = Parameter(default="front", choice=["front", "rear"])
write_output = Parameter(default=True, type=bool)
measurement = Measurement({"voltage_level": "100 V"}) # supply required parameters
# Get dictionary of all parameter values.
print(measurement.parameters)
# {'voltage_level': 100.0, 'current_compliance': 2.5e-05, 'terminal': 'front', 'write_output': True}
# Update parameter values
measurement.update_parameters({"current_compliance": "50 uA", "terminal": "rear"})
# Access individual parameter
print(measurement.voltage_level)
# 100.0
print(measurement.current_compliance)
# 5e-05
print(measurement.terminal)
# 'rear'
measurement.write_output = False
# AttributeError: can't set parameter: 'write_output'Use pint unit registry to convert between units.
from comet.utils import ureg, to_unit
quantity = ureg("25 nA").to("A")
print(to_unit(quantity, "mA"))
# 2.5e-05
print(to_unit("1200 V", "kV"))
# 1.2
print(to_unit(2.5, "pA"))
# 2.5To emulate one or more instruments using TCP sockets create a emulators.yaml
configuration file in your project directory specifying emulator module and
port.
emulators:
smu:
module: keithley.k2470
port: 11001
lcr:
module: keysight.e4980a
port: 11002
# Set message termination
termination: '\n'
# Set specific options
options:
cp.min: 2.5e-10
cp.max: 2.5e-9To spin up the emulator sockets run comet-emulator or alternatively
python -m comet.emulator.
comet-emulatorUse command line argument -f to use a custom configuration file.
comet-emulator -f custom_emulators.yamlSee package comet.emulator for available instrument emulators.
To use instrument emulators as resources use function open_emulator from
package comet.emulator to open a mock resource for an instrument.
from comet.emulator import open_emulator
with open_emulator("keithley.k2410") as res:
print(res.query("*IDN?"))Mock resources can be used like regular PyVISA resources in combination with instrument drivers.
from comet.driver.keithley import K2410
from comet.emulator import open_emulator
with open_emulator("keithley.k2410") as res:
instr = K2410(res)
print(instr.identify())To set emulator specific options either provide an options dict to
open_emulator or update the emulator.options dict directly.
from comet.emulator import open_emulator
options = {"correction_open_delay": 2.0}
with open_emulator("keysight.e4980a", options=options) as res:
res.emulator.options.update({
"cp.min": 2.5e-10,
"cp.max": 2.5e-9,
})COMET is licensed under the GNU General Public License Version 3.