Feature/eds parse factor and description (#378)

Author: marcovannoord

canopen/objectdictionary/eds.py

@@ -309,6 +309,22 @@ def build_variable(eds, section, node_id, index, subindex=0):
             var.value = _convert_variable(node_id, var.data_type, eds.get(section, "ParameterValue"))
         except ValueError:
             pass
+    # Factor, Description and Unit are not standard according to the CANopen specifications, but they are implemented in the python canopen package, so we can at least try to use them
+    if eds.has_option(section, "Factor"):
+        try:
+            var.factor = float(eds.get(section, "Factor"))
+        except ValueError:
+            pass
+    if eds.has_option(section, "Description"):
+        try:
+            var.description = eds.get(section, "Description")
+        except ValueError:
+            pass
+    if eds.has_option(section, "Unit"):
+        try:
+            var.unit = eds.get(section, "Unit")
+        except ValueError:
+            pass
     return var
 
 
@@ -376,6 +392,13 @@ def export_variable(var, eds):
         if getattr(var, 'max', None) is not None:
             eds.set(section, "HighLimit", var.max)
 
+        if getattr(var, 'description', '') != '':
+            eds.set(section, "Description", var.description)
+        if getattr(var, 'factor', 1) != 1:
+            eds.set(section, "Factor", var.factor)
+        if getattr(var, 'unit', '') != '':
+            eds.set(section, "Unit", var.unit)
+
     def export_record(var, eds):
         section = "%04X" % var.index
         export_common(var, eds, section)

test/sample.eds

@@ -938,3 +938,37 @@ AccessType=rw
 HighLimit=0x000000000000000A
 LowLimit=0x8000000000000009
 PDOMapping=0
+
+
+[3050]
+ParameterName=EDS file extensions
+SubNumber=0x7
+ObjectType=0x9
+
+[3050sub0]
+ParameterName=Highest subindex
+ObjectType=0x7
+DataType=0x0005
+AccessType=ro
+DefaultValue=0x02
+PDOMapping=0x0
+
+[3050sub1]
+ParameterName=FactorAndDescription
+ObjectType=0x7
+DataType=0x0004
+AccessType=ro
+PDOMapping=0x0
+Factor=0.1
+Description=This is the a test description
+Unit=mV
+
+[3050sub2]
+ParameterName=Error Factor and No Description
+ObjectType=0x7
+DataType=0x0004
+AccessType=ro
+PDOMapping=0x0
+Factor=ERROR
+Description=
+Unit=

test/test_eds.py

@@ -111,6 +111,18 @@ def test_dummy_variable(self):
     def test_dummy_variable_undefined(self):
         with self.assertRaises(KeyError):
             var_undef = self.od['Dummy0001']
+    
+    def test_reading_factor(self):
+        var = self.od['EDS file extensions']['FactorAndDescription']
+        self.assertEqual(var.factor, 0.1)
+        self.assertEqual(var.description, "This is the a test description")
+        self.assertEqual(var.unit,'mV')
+        var2 = self.od['EDS file extensions']['Error Factor and No Description']
+        self.assertEqual(var2.description, '')
+        self.assertEqual(var2.factor, 1)
+        self.assertEqual(var2.unit, '')
+        
+
 
     def test_comments(self):
         self.assertEqual(self.od.comments,