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#
# This file is part of the PyMeasure package.
#
# Copyright (c) 2013-2024 PyMeasure Developers
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
#
from pymeasure.instruments import Instrument
from pymeasure.instruments.validators import strict_discrete_set, truncated_discrete_set
from time import sleep
import numpy as np
class LakeShore425(Instrument):
""" Represents the LakeShore 425 Gaussmeter and provides
a high-level interface for interacting with the instrument
To allow user access to the LakeShore 425 Gaussmeter in Linux,
create the file:
:code:`/etc/udev/rules.d/52-lakeshore425.rules`, with contents:
.. code-block:: none
SUBSYSTEMS=="usb",ATTRS{idVendor}=="1fb9",ATTRS{idProduct}=="0401",MODE="0666",SYMLINK+="lakeshore425"
Then reload the udev rules with:
.. code-block:: bash
sudo udevadm control --reload-rules
sudo udevadm trigger
The device will be accessible through :code:`/dev/lakeshore425`.
"""
field = Instrument.measurement(
"RDGFIELD?",
""" Get the field in the current units """
)
unit = Instrument.control(
"UNIT?", "UNIT %d",
""" Control the units of the instrument,
which can take the values of G, T, Oe, or A/m. (str)""",
validator=strict_discrete_set,
values={'G': 1, 'T': 2, 'Oe': 3, 'A/m': 4},
map_values=True
)
range = Instrument.control(
"RANGE?", "RANGE %d",
""" Control the field range in
units of Gauss, which can take the values 35, 350, 3500, and
35,000 G. (float)""",
validator=truncated_discrete_set,
values={35: 1, 350: 2, 3500: 3, 35000: 4},
map_values=True
)
def __init__(self, adapter, name="LakeShore 425 Gaussmeter", **kwargs):
super().__init__(
adapter,
name,
asrl={'write_termination': "\n",
'read_termination': "\n", # from manual
'baud_rate': 57600,
'timeout': 500,
'parity': 1, # odd
'data_bits': 7
},
includeSCPI=False,
**kwargs
)
def auto_range(self):
""" Sets the field range to automatically adjust """
self.write("AUTO")
def dc_mode(self, wideband=True):
""" Sets up a steady-state (DC) measurement of the field """
if wideband:
self.mode = (1, 0, 1)
else:
self.mode = (1, 0, 2)
def ac_mode(self, wideband=True):
""" Sets up a measurement of an oscillating (AC) field """
if wideband:
self.mode = (2, 1, 1)
else:
self.mode = (2, 1, 2)
@property
def mode(self):
"""Control the mode, filter, and bandwidth settings."""
return tuple(self.values("RDGMODE?"))
@mode.setter
def mode(self, value):
mode, filter, band = value
self.write("RDGMODE %d,%d,%d" % (mode, filter, band))
def zero_probe(self):
""" Initiates the zero field sequence to calibrate the probe """
self.write("ZPROBE")
def measure(self, points, has_aborted=lambda: False, delay=1e-3):
"""Returns the mean and standard deviation of a given number
of points while blocking
"""
data = np.zeros(points, dtype=np.float32)
for i in range(points):
if has_aborted():
break
data[i] = self.field
sleep(delay)
return data.mean(), data.std()
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