diff --git a/script/local.py b/script/local.py
index 0eaf709..0290da6 100644
--- a/script/local.py
+++ b/script/local.py
@@ -38,10 +38,10 @@ def close_shutter():
 
 
 def transm_up(factor = 10.0):
-    transm.write(min(transm.read() * factor, 1.0))
+    transm.write(min(transm.position * factor, 1.0))
 
 def transm_down(factor = 10.0):
-    transm.write(transm.read() / factor)
+    transm.write(transm.position / factor)
     
 ###################################################################################################
 #  Pseudo-devices