diff --git a/Globals/GlobalFunctions.py b/Globals/GlobalFunctions.py
index 35820df..cf776c5 100644
--- a/Globals/GlobalFunctions.py
+++ b/Globals/GlobalFunctions.py
@@ -29,7 +29,9 @@
 
 
 # Update history function
-def updateHistory(w,b,m,a,pw,tag,Vread=g.Vread):
+def updateHistory(w,b,m,a,pw,tag,Vread=None):
+    if Vread is None:
+        Vread = g.Vread
     readTag='R'+str(g.readOption)
     if g.sessionMode==1:
         g.Mnow=m/2
diff --git a/source/version.txt b/source/version.txt
index cd2ea68..31884d7 100644
--- a/source/version.txt
+++ b/source/version.txt
@@ -1,2 +1,2 @@
 DO NOT MODIFY!
-1.5.1
+1.5.2