frappy_psi.thermofisher: fix bug reading limits

+ add proper description into cfg file

cfg/main/tfa_cfg.py

@@ -0,0 +1,20 @@
+Node('TFA10.psi.ch',
+     'thermofisher water bath',
+     'tcp://5000',
+     )
+
+Mod('io',
+    'frappy_psi.thermofisher.ThermFishIO',
+    'connection for ThermoFisher A10',
+    uri='tcp://ldm-fi-ts:3002',
+    )
+
+Mod('T',
+    'frappy_psi.thermofisher.TemperatureLoopA10',
+    'holder temperature',
+    io='io',
+    meaning=['temperature', 20],
+    target=Param(max=100),
+    tolerance=0.5,
+    settling_time=20,
+    )

frappy_psi/thermofisher.py

@@ -149,8 +149,8 @@ class TemperatureLoopA10(HasConvergence, HasIO, Drivable):
 
     def initialReads(self):
         super().initialReads()
-        self.target_max = min(self.target_max, self.get_par('RHTF'))
-        self.target_min = max(self.target_min, self.get_par('RLTF'))
+        self.target_max = min(self.target_max, self.get_par('HTF'))
+        self.target_min = max(self.target_min, self.get_par('LTF'))
 
     def switch_control_off(self, reason=None):
         self._off_reason = reason