From: W. Trevor King <wking@drexel.edu>
Date: Wed, 2 Jun 2010 05:21:31 +0000 (-0400)
Subject: Flip deflection sign for hooke.driver.wtk.
X-Git-Url: http://git.tremily.us/?a=commitdiff_plain;h=0b7572e55936977d9ce91c0e0932939708776161;p=hooke.git

Flip deflection sign for hooke.driver.wtk.

We want +deflection for +chain tension.
---

diff --git a/hooke/driver/wtk.py b/hooke/driver/wtk.py
index 46bf92e..640f056 100644
--- a/hooke/driver/wtk.py
+++ b/hooke/driver/wtk.py
@@ -185,7 +185,11 @@ class WTKDriver (Driver):
             * info['z piezo sensitivity (m/V)']
             )
 
-        ret[:,d_scol] = (
+        # Leading '-' because deflection voltage increases as the tip
+        # moves away from the surface, but it makes more sense to me
+        # to have it increase as it moves toward the surface (positive
+        # tension on the protein chain).
+        ret[:,d_scol] = -(
             (data[:,d_rcol]
              * info['deflection sensitivity (V/bit)']
              - info['deflection offset (V)'])