fix inheritance problem with mixin

- a mixin should not inherit from module then it has Parameters
- Parameters in mixins must be complete, not just overrides
- check precedence of read_<param> or handler

Change-Id: I72d9355a1982770d1a99d9552a20330103c97edb

secop_psi/ppms.py

@@ -128,8 +128,9 @@ class Main(Communicator):
         return data  # return data as string
 
 
-class PpmsBase(HasIodev, Readable):
+class PpmsMixin:
     """common base for all ppms modules"""
+
     iodev = Attached()
 
     pollerClass = Poller
@@ -139,7 +140,7 @@ class PpmsBase(HasIodev, Readable):
 
     # as this pollinterval affects only the polling of settings
     # it would be confusing to export it.
-    pollinterval = Parameter(export=False)
+    pollinterval = Parameter('', FloatRange(), needscfg=False, export=False)
 
     def initModule(self):
         self._iodev.register(self)
@@ -172,7 +173,7 @@ class PpmsBase(HasIodev, Readable):
             self.status = (self.Status.IDLE, '')
 
 
-class Channel(PpmsBase):
+class Channel(PpmsMixin, HasIodev, Readable):
     """channel base class"""
 
     value = Parameter('main value of channels', poll=True)
@@ -270,7 +271,7 @@ class BridgeChannel(Channel):
         return self.no, 0, 0, change.dcflag, change.readingmode, 0
 
 
-class Level(PpmsBase):
+class Level(PpmsMixin, HasIodev, Readable):
     """helium level"""
 
     level = IOHandler('level', 'LEVEL?', '%g,%d')
@@ -293,7 +294,7 @@ class Level(PpmsBase):
         return dict(value=level, status=(self.Status.IDLE, ''))
 
 
-class Chamber(PpmsBase, Drivable):
+class Chamber(PpmsMixin, HasIodev, Drivable):
     """sample chamber handling
 
     value is an Enum, which is redundant with the status text
@@ -368,7 +369,7 @@ class Chamber(PpmsBase, Drivable):
         return (change.target,)
 
 
-class Temp(PpmsBase, Drivable):
+class Temp(PpmsMixin, HasIodev, Drivable):
     """temperature"""
 
     temp = IOHandler('temp', 'TEMP?', '%g,%g,%d')
@@ -553,7 +554,7 @@ class Temp(PpmsBase, Drivable):
         self._stopped = True
 
 
-class Field(PpmsBase, Drivable):
+class Field(PpmsMixin, HasIodev, Drivable):
     """magnetic field"""
 
     field = IOHandler('field', 'FIELD?', '%g,%g,%d,%d')
@@ -562,6 +563,7 @@ class Field(PpmsBase, Drivable):
         PREPARED=150,
         PREPARING=340,
         RAMPING=370,
+        STABILIZING=380,
         FINALIZING=390,
     )
     # pylint: disable=invalid-name
@@ -584,7 +586,7 @@ class Field(PpmsBase, Drivable):
         2: (Status.PREPARING, 'switch warming'),
         3: (Status.FINALIZING, 'switch cooling'),
         4: (Status.IDLE, 'driven stable'),
-        5: (Status.FINALIZING, 'driven final'),
+        5: (Status.STABILIZING, 'driven final'),
         6: (Status.RAMPING, 'charging'),
         7: (Status.RAMPING, 'discharging'),
         8: (Status.ERROR, 'current error'),
@@ -690,7 +692,7 @@ class Field(PpmsBase, Drivable):
         self._stopped = True
 
 
-class Position(PpmsBase, Drivable):
+class Position(PpmsMixin, HasIodev, Drivable):
     """rotator position"""
 
     move = IOHandler('move', 'MOVE?', '%g,%g,%g')