Small addition to allow context managers

README.md

@@ -52,6 +52,7 @@ $ pip install git+https://github.com/OE-FET/keithley2600
 ## Usage
 
 Connect to the Keithley 2600 and perform some base commands:
+
 ```python
 from keithley2600 import Keithley2600
 
@@ -65,6 +66,25 @@ i = k.smua.measure.i()  # measures current at smuA
 k.smua.measure.v(k.smua.nvbuffer1)  # measures the voltage, stores the result in buffer
 k.smua.nvbuffer1.clear()  # clears nvbuffer1 of SMUA
 ```
+
+Alternatively, the device can be used in a context:
+
+```python
+from keithley2600 import Keithley2600
+
+with Keithley2600('TCPIP0::192.168.2.121::INSTR') as kth:
+    kth.reset()
+    smu = kth.smua
+    smu.sense = smu.SENSE_REMOTE
+    smu.source.limiti = 0.01  # mA
+    smu.source.autorangev = smu.AUTORANGE_ON
+    smu.source.func = smu.OUTPUT_DCVOLTS
+    smu.measure.autozero = smu.AUTOZERO_AUTO
+    smu.measure.autorangei = smu.AUTORANGE_ON
+    smu.measure.nplc = 16
+    smu.source.levelv = 3.3
+    smu.source.output = smu.OUTPUT_ON
+```
 Higher level commands defined in the driver:
 
 ```python

keithley2600/keithley_driver.py

@@ -568,6 +568,21 @@ def __init__(
 
     def __repr__(self) -> str:
         return f"<{self.__class__.__name__}({self.visa_address})>"
+
+    def __enter__(self):
+        """
+        Allows usage in contexts ("with Keithley2600() as kth:")
+
+        - cleaning the error-queue helps with faulty scripts that leave the SMU in a
+          weird state
+        - restarting the script often fails at basic tasks (like accessing keithley.smua)
+          because the TSP-Command-Set wasn't read successfully (or other weird behavior).
+        """
+        self.connection.write("errorqueue.clear()")
+        return self
+
+    def __exit__(self, *args):
+        self.disconnect()
 
     # =============================================================================
     # Connect to keithley