diff --git a/script/local.py b/script/local.py
index 1a45f931..c3fc26ef 100644
--- a/script/local.py
+++ b/script/local.py
@@ -158,14 +158,14 @@ def create_diag_datasets():
     group = get_current_group() + "attrs/"
     print group
     for f in diag_channels:
-        print group+f.getName() 
-        print ('s' if (type(f) is ch.psi.pshell.epics.ChannelString) else 'i')
         create_dataset(group+f.getName() , 's' if (type(f) is ch.psi.pshell.epics.ChannelString) else 'i')
-        print  "OK"
-    print "QUIT"
+
 def append_diag_datasets():
     group = get_current_group() + "attrs/"
     for f in diag_channels:
-        append_dataset(group+f.getName(), f.take())
+        x = f.take()
+        if x is None:
+            x = '' if (type(f) is ch.psi.pshell.epics.ChannelString) else float('nan')
+        append_dataset(group+f.getName(), x)
 
     
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