fixes in convergence, mercury, phytron, triton

secop_psi/mercury.py

@@ -341,6 +341,7 @@ class TemperatureLoop(TemperatureSensor, Loop, Drivable):
     enable_ramp = Parameter('enable ramp rate', BoolType(), readonly=False)
     setpoint = Parameter('working setpoint (differs from target when ramping)', FloatRange(0, unit='$'))
     auto_flow = Parameter('enable auto flow', BoolType(), readonly=False)
+    tolerance = Parameter(default=0.1)
     _last_setpoint_change = None
 
     def doPoll(self):
@@ -452,6 +453,7 @@ class ValvePos(HasInput, MercuryChannel, Drivable):
 class PressureLoop(PressureSensor, Loop, Drivable):
     channel_type = 'PRES,AUX'
     output_module = Attached(ValvePos, mandatory=False)
+    tolerance = Parameter(default=0.1)
 
     def read_control_active(self):
         active = self.query('PRES:LOOP:FAUT', off_on)