fixes in mb11/dil5

- no need fro second slot in TemperatureLoop, PressureLoop
- only ValvePos needs two slots
- added testwise heater to mix chamber

Change-Id: Iac4592d037a5e6a4f586041762992d75cc77e3de

secop_psi/triton.py

@@ -175,7 +175,7 @@ class FlowMeter(MercuryChannel, Readable):
         return self.query('FLOW:SIG:FLOW')
 
 
-class TemperatureSensor(mercury.TemperatureSensor):
+class ScannerChannel:
     # TODO: excitation, enable
     # TODO: switch on/off filter, check
     filter_time = Parameter('filter time', FloatRange(1, 200, unit='sec'), readonly=False)
@@ -203,5 +203,13 @@ class TemperatureSensor(mercury.TemperatureSensor):
         return self.change('TEMP:MEAS:PAUS', value)
 
 
-class TemperatureLoop(mercury.TemperatureLoop):
+class TemperatureSensor(ScannerChannel, mercury.TemperatureSensor):
     pass
+
+
+class TemperatureLoop(ScannerChannel, mercury.TemperatureLoop):
+    pass
+
+
+class HeaterOutput(mercury.HeaterOutput):
+    pass  # not sure if we need special handling of triton heater output: to be checked!