Oops, forgot the ['channel'].

diff --git a/pypiezo/surface.py b/pypiezo/surface.py
index 5fe6fe2032a0269ece6e6550f88a3e99b560dcb0..6461718cb45506817eff7828e080d6540375edf2 100644 (file)
--- a/pypiezo/surface.py
+++ b/pypiezo/surface.py
@@ -79,11 +79,11 @@ def _get_min_max_positions(piezo, axis_name, min_position=None,
     output_axis = piezo.axis_by_name(axis_name)
     if min_position is None:
         min_position = _base.convert_volts_to_bits(
-            output_axis.config,
+            output_axis.config['channel'],
             output_axis.config['minimum'])
     if max_position is None:
         max_position = _base.convert_volts_to_bits(
-            output_axis.config,
+            output_axis.config['channel'],
             output_axis.config['maximum'])
     return (min_position, max_position)