diff --git a/site_ansto/instrument/util/gen_sct.py b/site_ansto/instrument/util/gen_sct.py
index fadd550b..5c2478bc 100755
--- a/site_ansto/instrument/util/gen_sct.py
+++ b/site_ansto/instrument/util/gen_sct.py
@@ -218,7 +218,7 @@ def t_COMMENT(t):
   # No Return Value. Token discarded
 
 def t_FLOATER(t):
-  r'\d+\.\d*([eE]\d+)?'
+  r'-?\d+\.\d*([eE]\d+)?'
   try:
     t.value = float(t.value)
   except ValueError:
@@ -227,7 +227,7 @@ def t_FLOATER(t):
   return t
 
 def t_INTEGER(t):
-  r'\d+'
+  r'-?\d+'
   try:
     t.value = int(t.value)
   except ValueError: