Keithley 2450 SourceMeter

class pymeasure.instruments.keithley.Keithley2450(adapter, **kwargs)

Bases: pymeasure.instruments.instrument.Instrument, pymeasure.instruments.keithley.buffer.KeithleyBuffer

Represents the Keithely 2450 SourceMeter and provides a high-level interface for interacting with the instrument.

keithley = Keithley2450("GPIB::1")

keithley.apply_current()                # Sets up to source current
keithley.source_current_range = 10e-3   # Sets the source current range to 10 mA
keithley.compliance_voltage = 10        # Sets the compliance voltage to 10 V
keithley.source_current = 0             # Sets the source current to 0 mA
keithley.enable_source()                # Enables the source output

keithley.measure_voltage()              # Sets up to measure voltage

keithley.ramp_to_current(5e-3)          # Ramps the current to 5 mA
print(keithley.voltage)                 # Prints the voltage in Volts

keithley.shutdown()                     # Ramps the current to 0 mA and disables output
apply_current(current_range=None, compliance_voltage=0.1)

Configures the instrument to apply a source current, and uses an auto range unless a current range is specified. The compliance voltage is also set.

Parameters:
apply_voltage(voltage_range=None, compliance_current=0.1)

Configures the instrument to apply a source voltage, and uses an auto range unless a voltage range is specified. The compliance current is also set.

Parameters:
auto_range_source()

Configures the source to use an automatic range.

beep(frequency, duration)

Sounds a system beep.

Parameters:
  • frequency – A frequency in Hz between 65 Hz and 2 MHz
  • duration – A time in seconds between 0 and 7.9 seconds
buffer_data

Returns a numpy array of values from the buffer.

buffer_points

An integer property that controls the number of buffer points. This does not represent actual points in the buffer, but the configuration value instead.

check_errors()

Logs any system errors reported by the instrument.

compliance_current

A floating point property that controls the compliance current in Amps.

compliance_voltage

A floating point property that controls the compliance voltage in Volts.

config_buffer(points=64, delay=0)

Configures the measurement buffer for a number of points, to be taken with a specified delay.

Parameters:
  • points – The number of points in the buffer.
  • delay – The delay time in seconds.
current

Reads the current in Amps, if configured for this reading.

current_filter_count

A integer property that controls the number of readings that are acquired and stored in the filter buffer for the averaging

current_filter_state

A string property that controls if the filter is active.

current_filter_type

A String property that controls the filter’s type for the current. REP : Repeating filter MOV : Moving filter

current_nplc

A floating point property that controls the number of power line cycles (NPLC) for the DC current measurements, which sets the integration period and measurement speed. Takes values from 0.01 to 10, where 0.1, 1, and 10 are Fast, Medium, and Slow respectively.

current_output_off_state

Select the output-off state of the SourceMeter. HIMP : output relay is open, disconnects external circuitry. NORM : V-Source is selected and set to 0V, Compliance is set to 0.5% full scale of the present current range. ZERO : V-Source is selected and set to 0V, compliance is set to the programmed Source I value or to 0.5% full scale of the present current range, whichever is greater. GUAR : I-Source is selected and set to 0A

current_range

A floating point property that controls the measurement current range in Amps, which can take values between -1.05 and +1.05 A. Auto-range is disabled when this property is set.

disable_buffer()

Disables the connection between measurements and the buffer, but does not abort the measurement process.

disable_source()

Disables the source of current or voltage depending on the configuration of the instrument.

enable_source()

Enables the source of current or voltage depending on the configuration of the instrument.

error

Returns a tuple of an error code and message from a single error.

id

Requests and returns the identification of the instrument.

is_buffer_full()

Returns True if the buffer is full of measurements.

max_current

Returns the maximum current from the buffer

max_resistance

Returns the maximum resistance from the buffer

max_voltage

Returns the maximum voltage from the buffer

maximums

Returns the calculated maximums for voltage, current, and resistance from the buffer data as a list.

mean_current

Returns the mean current from the buffer

mean_resistance

Returns the mean resistance from the buffer

mean_voltage

Returns the mean voltage from the buffer

means

Reads the calculated means (averages) for voltage, current, and resistance from the buffer data as a list.

measure_current(nplc=1, current=0.000105, auto_range=True)

Configures the measurement of current.

Parameters:
  • nplc – Number of power line cycles (NPLC) from 0.01 to 10
  • current – Upper limit of current in Amps, from -1.05 A to 1.05 A
  • auto_range – Enables auto_range if True, else uses the set current
measure_resistance(nplc=1, resistance=210000.0, auto_range=True)

Configures the measurement of resistance.

Parameters:
  • nplc – Number of power line cycles (NPLC) from 0.01 to 10
  • resistance – Upper limit of resistance in Ohms, from -210 MOhms to 210 MOhms
  • auto_range – Enables auto_range if True, else uses the set resistance
measure_voltage(nplc=1, voltage=21.0, auto_range=True)

Configures the measurement of voltage.

Parameters:
  • nplc – Number of power line cycles (NPLC) from 0.01 to 10
  • voltage – Upper limit of voltage in Volts, from -210 V to 210 V
  • auto_range – Enables auto_range if True, else uses the set voltage
min_current

Returns the minimum current from the buffer

min_resistance

Returns the minimum resistance from the buffer

min_voltage

Returns the minimum voltage from the buffer

minimums

Returns the calculated minimums for voltage, current, and resistance from the buffer data as a list.

ramp_to_current(target_current, steps=30, pause=0.02)

Ramps to a target current from the set current value over a certain number of linear steps, each separated by a pause duration.

Parameters:
  • target_current – A current in Amps
  • steps – An integer number of steps
  • pause – A pause duration in seconds to wait between steps
ramp_to_voltage(target_voltage, steps=30, pause=0.02)

Ramps to a target voltage from the set voltage value over a certain number of linear steps, each separated by a pause duration.

Parameters:
  • target_voltage – A voltage in Amps
  • steps – An integer number of steps
  • pause – A pause duration in seconds to wait between steps
reset()

Resets the instrument and clears the queue.

reset_buffer()

Resets the buffer.

resistance

Reads the resistance in Ohms, if configured for this reading.

resistance_nplc

A floating point property that controls the number of power line cycles (NPLC) for the 2-wire resistance measurements, which sets the integration period and measurement speed. Takes values from 0.01 to 10, where 0.1, 1, and 10 are Fast, Medium, and Slow respectively.

resistance_range

A floating point property that controls the resistance range in Ohms, which can take values from 0 to 210 MOhms. Auto-range is disabled when this property is set.

shutdown()

Ensures that the current or voltage is turned to zero and disables the output.

source_current

A floating point property that controls the source current in Amps.

source_current_delay

A floating point property that sets a manual delay for the source after the output is turned on before a measurement is taken. When this property is set, the auto delay is turned off. Valid values are between 0 [seconds] and 999.9999 [seconds].

source_current_delay_auto

A boolean property that enables or disables auto delay. Valid values are True and False.

source_current_range

A floating point property that controls the source current range in Amps, which can take values between -1.05 and +1.05 A. Auto-range is disabled when this property is set.

source_enabled

Reads a boolean value that is True if the source is enabled.

source_mode

A string property that controls the source mode, which can take the values ‘current’ or ‘voltage’. The convenience methods apply_current() and apply_voltage() can also be used.

source_voltage

A floating point property that controls the source voltage in Volts.

source_voltage_delay

A floating point property that sets a manual delay for the source after the output is turned on before a measurement is taken. When this property is set, the auto delay is turned off. Valid values are between 0 [seconds] and 999.9999 [seconds].

source_voltage_delay_auto

A boolean property that enables or disables auto delay. Valid values are True and False.

source_voltage_range

A floating point property that controls the source voltage range in Volts, which can take values from -210 to 210 V. Auto-range is disabled when this property is set.

standard_devs

Returns the calculated standard deviations for voltage, current, and resistance from the buffer data as a list.

start_buffer()

Starts the buffer.

std_current

Returns the current standard deviation from the buffer

std_resistance

Returns the resistance standard deviation from the buffer

std_voltage

Returns the voltage standard deviation from the buffer

stop_buffer()

Aborts the buffering measurement, by stopping the measurement arming and triggering sequence. If possible, a Selected Device Clear (SDC) is used.

triad(base_frequency, duration)

Sounds a musical triad using the system beep.

Parameters:
  • base_frequency – A frequency in Hz between 65 Hz and 1.3 MHz
  • duration – A time in seconds between 0 and 7.9 seconds
trigger()

Executes a bus trigger.

use_front_terminals()

Enables the front terminals for measurement, and disables the rear terminals.

use_rear_terminals()

Enables the rear terminals for measurement, and disables the front terminals.

voltage

Reads the voltage in Volts, if configured for this reading.

voltage_filter_count

A integer property that controls the number of readings that are acquired and stored in the filter buffer for the averaging

voltage_filter_type

A String property that controls the filter’s type for the current. REP : Repeating filter MOV : Moving filter

voltage_nplc

A floating point property that controls the number of power line cycles (NPLC) for the DC voltage measurements, which sets the integration period and measurement speed. Takes values from 0.01 to 10, where 0.1, 1, and 10 are Fast, Medium, and Slow respectively.

voltage_output_off_state

Select the output-off state of the SourceMeter. HIMP : output relay is open, disconnects external circuitry. NORM : V-Source is selected and set to 0V, Compliance is set to 0.5% full scale of the present current range. ZERO : V-Source is selected and set to 0V, compliance is set to the programmed Source I value or to 0.5% full scale of the present current range, whichever is greater. GUAR : I-Source is selected and set to 0A

voltage_range

A floating point property that controls the measurement voltage range in Volts, which can take values from -210 to 210 V. Auto-range is disabled when this property is set.

wait_for_buffer(should_stop=<function KeithleyBuffer.<lambda>>, timeout=60, interval=0.1)

Blocks the program, waiting for a full buffer. This function returns early if the should_stop function returns True or the timeout is reached before the buffer is full.

Parameters:
  • should_stop – A function that returns True when this function should return early
  • timeout – A time in seconds after which this function should return early
  • interval – A time in seconds for how often to check if the buffer is full
wires

An integer property that controls the number of wires in use for resistance measurements, which can take the value of 2 or 4.