Model 121 Programmable DC Current Source

The Lake Shore Model 121 provides low-noise, stable current.

More information about the instrument can be found on our website including the manual which has a list of all commands and queries.

Example Scripts

Setting a current

from lakeshore import Model121

# Connect to Model 121 over USB
current_source = Model121()

# Set current source to 150 nA and start
current_source.set_current(150e-9)

# Query and print the current source level
print(current_source.get_current())

Instrument methods

class lakeshore.model_121.Model121(serial_number=None, com_port=None, baud_rate=57600, data_bits=7, stop_bits=1, parity='O', flow_control=False, handshaking=False, timeout=2.0, ip_address=None, tcp_port=7777, **kwargs)

A class object representing the Lake Shore Model 121 programmable DC current source.

command(command_string)

Sends a command to the instrument.

Args:: command_string (str): A serial command.

set_current(current)

Set and start outputting a specific current from the instrument.

Switches to the user current range and applies the specified current. Current can be set between 100nA and 100mA. The sign of the current determines the polarity of the output.

Args:

current (float): New current value as a floating point number. The minimum value is 100e-9 A and the maximum: is 100e-3 A. Positive or negative. Up to three significant digits.

get_current()

Returns the present user current setting in Amps.

Returns:: float: User current value in Amps.

enable_current(): Enables current source output.

disable_current(): Disables current source output.

reset_instrument(): Sets instrument parameters to power-up settings.

set_display_brightness(brightness_level)

Sets the display contrast for the front panel seven-segment display.

A higher number makes the display brighter. The default setting is 8. The display can be turned off by setting the brightness to 0.

Args:: brightness_level (int): The display brightness (0-15).

get_display_brightness()

Gets the display contrast for the front panel seven-segment display.

A higher number makes the display brighter. The default setting is 8. Brightness level 0 means the display is turned off.

Returns:: int: The display brightness (0-15).

get_compliance_limit_status()

Returns the voltage compliance status of the current source output.

Returns:: bool: False = normal operation. True = in compliance limit.

set_factory_defaults(): Sets all configuration values to factory defaults and resets the instrument.

lock_front_panel(): Locks the front panel keypad.

unlock_front_panel(): Unlocks the front panel keypad.

get_front_panel_lock_status()

Returns if the front panel keypad is locked or not.

Returns:: bool: True = Locked, False = Unlocked.

set_power_up_enable(state)

Specifies whether the output remains on or shuts off after power cycle.

Args:: state (bool): True = Enabled, False = Disabled.

save_current_state()

Saves the present range, polarity, and user current value.

This saved state will be loaded on future power ups.

connect_tcp(ip_address, tcp_port, timeout): Establishes a TCP connection with the instrument on the specified IP address.

connect_usb(serial_number=None, com_port=None, baud_rate=None, data_bits=None, stop_bits=None, parity=None, timeout=None, handshaking=None, flow_control=None): Establish a serial USB connection.

disconnect_tcp(): Disconnect the TCP connection.

disconnect_usb(): Disconnect the USB connection.

query(query_string)

Send a query to the instrument and return the response.

Args:

query_string (str):: A serial query ending in a question mark.

Returns:

The instrument query response as a string.

write(command_string)

Alias of command. Send a command to the instrument.

Args:

command_string (str):: A serial command.