#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
Provides support for the Lakeshore 370 AC resistance bridge.
"""
# IMPORTS #####################################################################
from __future__ import absolute_import
from __future__ import division
from builtins import range
import quantities as pq
from instruments.generic_scpi import SCPIInstrument
from instruments.util_fns import ProxyList
# CLASSES #####################################################################
[docs]class Lakeshore370(SCPIInstrument):
"""
The Lakeshore 370 is a multichannel AC resistance bridge for use in low
temperature dilution refridgerator setups.
Example usage:
>>> import instruments as ik
>>> bridge = ik.lakeshore.Lakeshore370.open_gpibusb('/dev/ttyUSB0', 1)
>>> print(bridge.channel[0].resistance)
"""
def __init__(self, filelike):
super(Lakeshore370, self).__init__(filelike)
# Disable termination characters and enable EOI
self.sendcmd('IEEE 3,0')
# INNER CLASSES ##
[docs] class Channel(object):
"""
Class representing a sensor attached to the Lakeshore 370.
.. warning:: This class should NOT be manually created by the user. It is
designed to be initialized by the `Lakeshore370` class.
"""
def __init__(self, parent, idx):
self._parent = parent
self._idx = idx + 1
# PROPERTIES ##
@property
def resistance(self):
"""
Gets the resistance of the specified sensor.
:units: Ohm
:rtype: `~quantities.quantity.Quantity`
"""
value = self._parent.query('RDGR? {}'.format(self._idx))
return pq.Quantity(float(value), pq.ohm)
# PROPERTIES ##
@property
def channel(self):
"""
Gets a specific channel object. The desired channel is specified like
one would access a list.
For instance, this would query the resistance of the first channel::
>>> import instruments as ik
>>> bridge = ik.lakeshore.Lakeshore370.open_serial("COM5")
>>> print(bridge.channel[0].resistance)
The Lakeshore 370 supports up to 16 channels (index 0-15).
:rtype: `~Lakeshore370.Channel`
"""
return ProxyList(self, Lakeshore370.Channel, range(16))