Improve documentation

camrasdevices.py

@@ -4,8 +4,8 @@ from astropy.units import Quantity
 import hpib
 import serial.threaded
 
-serial_port = serial.Serial("/dev/ttyUSB0")
-command_thread = serial.threaded.ReaderThread(serial_port, hpib.GPIBProtocol)
+command_thread = None
+
 
 class CamrasHpibDevice(object):
     """Wrapper around HPIB commands"""
@@ -15,6 +15,10 @@ class CamrasHpibDevice(object):
             command_thread.start()
         self.hpib_address = address
 
+        if not command_thread:
+            serial_port = serial.Serial("/dev/ttyUSB0")
+            command_thread = serial.threaded.ReaderThread(serial_port, hpib.GPIBProtocol)
+
     @property
     def frequency(self):
         """Returns the frequency of the device as an astropy Quantity.
@@ -26,7 +30,11 @@ class CamrasHpibDevice(object):
 
     @frequency.setter
     def frequency(self, freq):
-        """Set the device to the specified frequency. Throws a RuntimeError if failed"""
+        """Set the device to the specified frequency. Throws a RuntimeError if failed
+
+        Args:
+            freq (Union[float, Quantity]): new frequency. If no unit present, assume Hz
+        """
         if isinstance(freq, Quantity):
             freq = freq.to(u.Hz).value
         command_thread.protocol.command("freq {:d} Hz".format(int(freq)), address=self.hpib_address)
@@ -39,16 +47,16 @@ class Receiver(CamrasHpibDevice):
     """Wrapper around HPIB commands for the Rohde & Schwartz receiver"""
 
     def __init__(self, **kwargs):
-        super(Receiver, self).__init__(1, **kwargs)
+        super(Receiver, self).__init__(1)
 
 class LocalOscillator(CamrasHpibDevice):
     """Wrapper around HPIB commands for the local oscillator"""
 
     def __init__(self, **kwargs):
-        super(LocalOscillator, self).__init__(28, **kwargs)
+        super(LocalOscillator, self).__init__(28)
 
 class ClockGenerator(CamrasHpibDevice):
     """Wrapper around HPIB commands for the clock generator (should be at 140MHz)"""
 
     def __init__(self, **kwargs):
-        super(SignalGenerator, self).__init__(14, **kwargs)
+        super(ClockGenerator, self).__init__(14)

hpib.py

-import serial
 import serial.threaded
 import threading
-import time
-import re
-import platform
-import sys
-import datetime
 
 try:
     import queue
@@ -14,6 +8,8 @@ except ImportError:
 
 
 class GPIBProtocol(serial.threaded.LineReader):
+    """Implementation of the GPIB protocol"""
+
     TERMINATOR = b'\n'
 
     def __init__(self):
@@ -22,6 +18,7 @@ class GPIBProtocol(serial.threaded.LineReader):
         self.lock = threading.Lock()
 
     def init_hpib(self):
+        """Execute some setup commands for the HPIB system"""
         with self.lock:
             self.write_line("++savecfg 0")
             self.write_line("++auto 0")
@@ -32,6 +29,17 @@ class GPIBProtocol(serial.threaded.LineReader):
             self.write_line("++read_tmo_ms 500")
 
     def command(self, command, timeout=0.2, address=None):
+        """Execute a HPIB command
+
+        Args:
+            command (str): Command to execute (can be a query)
+            timeout (float): How long to wait for a reply
+            address (int): HPIB address to send the command to
+
+        Returns:
+             If the command contains '?', the value returned by
+             the HPIB device is returned, else None.
+        """
         with self.lock:
             if address:
                 self.write_line("++addr {:d}".format(address))
@@ -41,12 +49,12 @@ class GPIBProtocol(serial.threaded.LineReader):
                 # The command was a query, wait for response
                 try:
                     line = self.responses.get(timeout=timeout)
-                except Empty:
-                    print("No frequency returned")
+                except queue.Empty:
                     return None
                 return line
             else:
                 pass
 
     def handle_line(self, line):
+        """Handle input from serial port, put it in the queue"""
         self.responses.put(line)