Keithley 2280S (alexforencich#2)

* Driver for Keithley 2280S power supply

* Added more instrument functionality

* Add ADC auto-zero functionality for faster sampling rates.

* Add more measurement functionality. Make all functions support multichannel instruments.

* Add more measurement functionality

* Add more trigger functionality

* Change _output_fetch_measurement() so that all data is fetched in a single instrument call

Author: avicent

README.md

@@ -43,6 +43,7 @@ Instrument standard from the [IVI foundation](http://www.ivifoundation.org/).
     * Chroma 62000P series
     * Rigol DP800 series
     * Rigol DP1000 series
+    * Keithley (Tektronix) 2280S series
     * Tektronix PS2520G/PS2521G
   * RF Power Meters (pwrmeter):
     * Agilent 436A

ivi/__init__.py

@@ -50,6 +50,7 @@
         "colby",
         "ics",
         "jdsu",
+        "keithley",
         "lecroy",
         "rigol",
         "rohdeschwarz",

ivi/interface/pyvisa.py

@@ -34,6 +34,9 @@
         # New style PyVISA
         visa_rm = visa.ResourceManager()
         visa_instrument_opener = visa_rm.open_resource
+    except OSError:
+        visa_rm = visa.ResourceManager('@py')
+        visa_instrument_opener = visa_rm.open_resource
     except AttributeError:
         # Old style PyVISA
         visa_instrument_opener = visa.instrument

ivi/keithley/__init__.py

@@ -0,0 +1,29 @@
+"""
+
+Python Interchangeable Virtual Instrument Library
+
+Copyright (c) 2017 Jonas Långbacka, Acconeer Ab
+
+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.
+
+"""
+
+# DC Power Supplies
+from .keithley2280S import keithley2280S
+#from .keithley2280S import keithley2280S_60_3