frappy_psi.furnace: small improvments

- got not ail when _interlock is None

Change-Id: Ic56bf7b7beeabc39bb8ced3388c7d0f14845463a

frappy_psi/furnace.py

@@ -21,14 +21,12 @@
 
 from frappy.core import Module, Writable, Attached, Parameter, FloatRange, Readable, \
      BoolType, ERROR, IDLE, Command, StringType
-from frappy.errors import ImpossibleError
+from frappy.errors import ImpossibleError, ConfigError
 from frappy.ctrlby import WrapControlledBy
 from frappy.lib import clamp, merge_status
 from frappy_psi.picontrol import PImixin
 from frappy_psi.convergence import HasConvergence
 from frappy_psi.ionopimax import CurrentInput, LogVoltageInput
-import frappy_psi.tdkpower as tdkpower
-import frappy_psi.bkpower as bkpower
 
 
 class Interlocks(Writable):
@@ -161,7 +159,7 @@ class Interlocks(Writable):
     def get_violations(self):
         violations = {False: [], True: []}
         if self.flowswitch and self.flowswitch.value == 0:
-            violations[seld._disable_flow_check].append('no cooling water')
+            violations[self._disable_flow_check].append('no cooling water')
         for sensor, limitname, disabled in self._sensor_checks:
             if sensor.status[0] >= ERROR:
                 violations[disabled].append(f'error at {sensor.name}: {sensor.status[1]}')
@@ -196,7 +194,9 @@ class PI(HasConvergence, PImixin, Writable):
         return self.input_module.value
 
     def read_status(self):
-        violations = self.callback_func(query=True)
+        if not self._interlock:
+            return super().read_status()
+        violations = self._interlock.interlock_callback(query=True)
         status = (ERROR, violations) if violations else super().read_status()
         return merge_status(status, self.input_module.status)