Keithley 6485 + Keithley 6517b support

src/instruments/glassman/glassmanfr.py

@@ -1,6 +1,6 @@
 #!/usr/bin/env python
 #
-# hpe3631a.py: Driver for the Glassman FR Series Power Supplies
+# glassmanfr.py: Driver for the Glassman FR Series Power Supplies
 #
 # © 2019 Francois Drielsma (francois.drielsma@gmail.com).
 #
@@ -89,6 +89,7 @@ def __init__(self, filelike):
         self._device_timeout = False
         self._voltage = 0.0 * u.volt
         self._current = 0.0 * u.amp
+        self.device_timeout = False
 
     # ENUMS ##
 
@@ -159,7 +160,9 @@ def voltage(self):
 
     @voltage.setter
     def voltage(self, newval):
-        self.set_status(voltage=assume_units(newval, u.volt))
+        voltage = assume_units(newval, u.volt)
+        self.set_status(voltage=voltage)
+        self._voltage = voltage
 
     @property
     def current(self):
@@ -173,7 +176,9 @@ def current(self):
 
     @current.setter
     def current(self, newval):
-        self.set_status(current=assume_units(newval, u.amp))
+        current = assume_units(newval, u.amp)
+        self.set_status(current=current)
+        self._current = current
 
     @property
     def voltage_sense(self):

src/instruments/keithley/__init__.py

@@ -9,4 +9,6 @@
 from .keithley580 import Keithley580
 from .keithley2182 import Keithley2182
 from .keithley6220 import Keithley6220
+from .keithley6485 import Keithley6485
 from .keithley6514 import Keithley6514
+from .keithley6517b import Keithley6517b

src/instruments/keithley/keithley6485.py

@@ -0,0 +1,158 @@
+#!/usr/bin/env python
+#
+# keithley6485.py: Driver for the Keithley 6485 picoammeter
+#
+# © 2019 Francois Drielsma (francois.drielsma@gmail.com).
+#
+# This file is a part of the InstrumentKit project.
+# Licensed under the AGPL version 3.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+"""
+Driver for the Keithley 6485 picoammeter.
+
+Originally contributed and copyright held by Francois Drielsma
+(francois.drielsma@gmail.com).
+
+An unrestricted license has been provided to the maintainers of the Instrument
+Kit project.
+"""
+
+# IMPORTS #####################################################################
+
+from instruments.generic_scpi import SCPIInstrument
+from instruments.units import ureg as u
+from instruments.util_fns import bool_property
+
+# CLASSES #####################################################################
+
+
+class Keithley6485(SCPIInstrument):
+    """
+    The `Keithley 6485` is an electrometer capable of doing sensitive current,
+    charge, voltage and resistance measurements.
+
+    WARNING: Must set the terminator to `LF` on the define for this to work.
+
+    Example usage:
+
+    >>> import instruments as ik
+    >>> import instruments.units as u
+    >>> dmm = ik.keithley.Keithley6485.open_serial('/dev/ttyUSB0', baud=9600)
+    >>> dmm.measure()
+    <Quantity(0.000123, 'ampere')>
+    """
+
+    def __init__(self, filelike):
+        """
+        Resets device to be read, disables zero check.
+        """
+        super().__init__(filelike)
+        self.reset()
+        self.zero_check = False
+
+    # PROPERTIES ##
+
+    zero_check = bool_property(
+        "SYST:ZCH",
+        inst_true="ON",
+        inst_false="OFF",
+        doc="""
+        Gets/sets the zero checking status of the Keithley 6485.
+        """,
+    )
+
+    zero_correct = bool_property(
+        "SYST:ZCOR",
+        inst_true="ON",
+        inst_false="OFF",
+        doc="""
+        Gets/sets the zero correcting status of the Keithley 6485.
+        """,
+    )
+
+    @property
+    def auto_range(self):
+        """
+        Gets/sets the auto range setting
+
+        :type: `bool`
+        """
+        # pylint: disable=no-member
+        out = self.query("RANG:AUTO?")
+        return out == "1"
+
+    @auto_range.setter
+    def auto_range(self, newval):
+        # pylint: disable=no-member
+        self.sendcmd("RANG:AUTO {}".format("1" if newval else "0"))
+
+    @property
+    def input_range(self):
+        """
+        Gets/sets the upper limit of the current range.
+
+        :type: `~pint.Quantity`
+        """
+        # pylint: disable=no-member
+        out = self.query("RANG?")
+        return float(out) * u.amp
+
+    @input_range.setter
+    def input_range(self, newval):
+        # pylint: disable=no-member
+        val = newval.to(u.amp).magnitude
+        if val not in self._valid_range():
+            raise ValueError("Unexpected range limit for currently selected mode.")
+        self.sendcmd(f"RANG {val:e}")
+
+    # METHODS ##
+
+    def fetch(self):
+        """
+        Request the latest post-processed readings using the current mode.
+        (So does not issue a trigger)
+        Returns a tuple of the form (reading, timestamp, trigger_count)
+        """
+        return self._parse_measurement(self.query("FETC?"))
+
+    def read_measurements(self):
+        """
+        Trigger and acquire readings using the current mode.
+        Returns a tuple of the form (reading, timestamp, trigger_count)
+        """
+        return self._parse_measurement(self.query("READ?"))
+
+    def measure(self):
+        """
+        Trigger and acquire readings.
+        Returns the measurement reading only.
+        """
+        return self.read_measurements()[0]
+
+    # PRIVATE METHODS ##
+
+    @staticmethod
+    def _valid_range():
+        return (2e-9, 20e-9, 200e-9, 2e-6, 20e-6, 200e-6, 2e-3, 20e-3)
+
+    @staticmethod
+    def _parse_measurement(ascii):
+        # Split the string in three comma-separated parts (value, time, number of triggers)
+        vals = ascii.split(",")
+        reading = float(vals[0][:-1]) * u.amp
+        timestamp = float(vals[1]) * u.second
+        trigger_count = int(float(vals[2]))
+        return reading, timestamp, trigger_count