Add min-slope-ratio option to BumpConfig.

I was running into trouble moving to the surface with extremely long
cantilevers, as the difference between the contact slope and
non-contact drift was smaller than my hardcoded cutoff.  Now the
cutoff is configurable.

diff --git a/calibcant/config.py b/calibcant/config.py
index c80e791c1cfe3307a66b67a703bbf39ffc9e518e..2cb32da01338ab9a390619b379167bdfca334b5e 100644 (file)
--- a/calibcant/config.py
+++ b/calibcant/config.py
@@ -88,6 +88,13 @@ class BumpConfig (_config.Config):
             help=('Maximum deflection in volts in case of stepper positioning '
                   'to achieve the initial position.'),
             default=2.0),
             help=('Maximum deflection in volts in case of stepper positioning '
                   'to achieve the initial position.'),
             default=2.0),

+        _config.FloatSetting(
+            name='min-slope-ratio',
+            help=('Set the minimum ratio between the deflection/displacement '
+                  'of the contact and the non-contact regions for bumps '
+                  'seeking the surface.  Bumps without sufficient difference '
+                  'assume they need to move closer to find the surface.'),
+            default=10.0),

         _config.IntegerSetting(
             name='far-steps',
             help=('Number of stepper steps to move "far" away from the '
         _config.IntegerSetting(
             name='far-steps',
             help=('Number of stepper steps to move "far" away from the '