Added documentation

Change-Id: Id6e26a4c28fe080a55099cd54d0fa85c15946657

frappy_psi/bridge.py

@@ -15,7 +15,7 @@
 #
 # Module authors: Oksana Shliakhtun <oksana.shliakhtun@psi.ch>
 # *****************************************************************************
-
+"""Stanford Research Systems SIM900 Mainframe"""
 
 import re
 from frappy.core import StringIO, HasIO, Readable, \
@@ -24,6 +24,11 @@ from frappy.core import StringIO, HasIO, Readable, \
 
 
 def string_to_value(value):
+    """
+    Converting the value to float, removing the units, converting the prefix into the number.
+    :param value: value
+    :return: float value without units
+    """
     value_with_unit = re.compile(r'(\d+)([pnumkMG]?)')
     value, pfx = value_with_unit.match(value).groups()
     pfx_dict = {'p': 1e-12, 'n': 1e-9, 'u': 1e-6, 'm': 1e-3, 'k': 1e3, 'M': 1e6, 'G': 1e9}
@@ -33,6 +38,12 @@ def string_to_value(value):
 
 
 def find_idx(list_of_values, target):
+    """
+    Search for the nearest value and index from the given range for the given target.
+    :param list_of_values: range of values
+    :param target: target
+    :return: closest index and closest value
+    """
     target = float(target)
     cl_idx = None
     cl_value = float('inf')
@@ -49,6 +60,9 @@ def find_idx(list_of_values, target):
 
 
 class BridgeIO(StringIO):
+    """_\n is placed at the beginning of each command to distinguish
+    the previous response with a possible asynchronous response from the actual value returned by the method. """
+
     end_of_line = '\n'
     identification = [('_\n*IDN?', r'Stanford_Research_Systems,.*')]
 
@@ -57,9 +71,15 @@ class Base(HasIO):
     port = Property('modules port', IntRange(0, 15))
 
     def communicate(self, command):
+        """
+        Connection to the particular module x.
+        :param command: command
+        :return: return
+        """
         return self.io.communicate(f'_\nconn {self.port:x},"_\n"\n{command}')
 
     def query(self, command):
+        """converting to float"""
         return float(self.communicate(command))
 
 
@@ -142,6 +162,7 @@ class Resistance(Base, Readable):
         return self.query('rval?')
 
     def read_irange(self):
+        """index of the resistance value according to the range"""
         return self.query('rang?')
 
     def write_irange(self, idx):
@@ -151,6 +172,7 @@ class Resistance(Base, Readable):
         return value
 
     def read_range(self):
+        """value of the resistance range"""
         idx = self.read_irange()
         name = self.RES_RANGE[idx]
         return string_to_value(name)
@@ -161,12 +183,14 @@ class Resistance(Base, Readable):
         return cl_value
 
     def read_output_offset(self):
+        """Output offset, can be set by user. This is the value subtracted from the measured value"""
         return self.query('rset?')
 
     def write_output_offset(self, output_offset):
         self.query(f'rset {output_offset};rset?')
 
     def read_itc(self):
+        """index of the temperature constant value according to the range"""
         return self.query('tcon?')
 
     def write_itc(self, itc):
@@ -192,6 +216,7 @@ class Resistance(Base, Readable):
         return value
 
     def read_iexct(self):
+        """index of the excitation value according to the range"""
         return int(self.query('exci?'))
 
     def write_iexct(self, iexct):
@@ -221,6 +246,10 @@ class Resistance(Base, Readable):
         return string_to_value(name)
 
     def read_phase_hold(self):
+        """
+        Set the phase hold mode (if on - phase is assumed to be zero).
+        :return: 0 - off, 1 - on
+        """
         return int(self.communicate('phld?'))
 
     def write_phase_hold(self, phase_hold):