frappy_psi: added channels

cfg/tcs_cfg.py

@@ -9,9 +9,16 @@ Mod('io',
     uri='linse-leiden-ts:3005',
     )
 
-Mod('swh',
+Mod('still_htr',
     'frappy_psi.tcs.Heater',
-    'magnet switch heater',
+    'still heater',
     io='io',
-    channel=1,
+    channel=2,
+    )
+
+Mod('mix_htr',
+    'frappy_psi.tcs.Heater',
+    'mixing chamber heater',
+    io='io',
+    channel=3,
     )