diff --git a/frappy/modules.py b/frappy/modules.py
index 0105c51..9844b2f 100644
--- a/frappy/modules.py
+++ b/frappy/modules.py
@@ -834,7 +834,7 @@ class Readable(Module):
     value = Parameter('current value of the module', FloatRange())
     status = Parameter('current status of the module', StatusType(Status),
                        default=(StatusType.IDLE, ''))
-    pollinterval = Parameter('default poll interval', FloatRange(0.1, 120),
+    pollinterval = Parameter('default poll interval', FloatRange(0.1, 120, unit='s'),
                              default=5, readonly=False, export=True)
 
     def doPoll(self):
diff --git a/frappy_psi/phytron.py b/frappy_psi/phytron.py
index e4a6174..d4680af 100644
--- a/frappy_psi/phytron.py
+++ b/frappy_psi/phytron.py
@@ -69,9 +69,9 @@ class Motor(HasOffset, PersistentMixin, HasIO, Drivable):
     encoder_tolerance = Parameter('', FloatRange(unit='deg'), readonly=False, default=0.01)
     sign = PersistentParam('', IntRange(-1,1), readonly=False, default=1)
     encoder = Parameter('encoder reading', FloatRange(unit='deg'))
-    backlash = Parameter("""backlash compensation\n
-                         offset for always approaching from the same side""",
-                         FloatRange(unit='deg'), readonly=False, default=0)
+    backlash = PersistentParam("""backlash compensation\n
+                               offset for always approaching from the same side""",
+                               FloatRange(unit='deg'), readonly=False, default=0)
     target_min = Limit()
     target_max = Limit()
     alive_time = PersistentParam('alive time for detecting restarts',