diff --git a/site_ansto/instrument/runsics.py b/site_ansto/instrument/runsics.py
index 5cef6dd1..64fe1e7e 100755
--- a/site_ansto/instrument/runsics.py
+++ b/site_ansto/instrument/runsics.py
@@ -61,7 +61,7 @@ def start_cmd(server, args):
     else:
         soffset = ''
     sicsenv = {
-        'none':       None,
+        'none':      '',
         'fullsim':   'SICS_SIMULATION=full%s' % soffset,
         'fakedev':   'SICS_SIMULATION=fakedev%s' % soffset,
         'scriptval': 'SICS_SIMULATION=script_validator%s' % soffset