diff --git a/site_ansto/instrument/config/environment/pressure/sct_pfeiffer_tpg261.tcl b/site_ansto/instrument/config/environment/pressure/sct_pfeiffer_tpg261.tcl
index 13a5eb4b..f600f79a 100644
--- a/site_ansto/instrument/config/environment/pressure/sct_pfeiffer_tpg261.tcl
+++ b/site_ansto/instrument/config/environment/pressure/sct_pfeiffer_tpg261.tcl
@@ -122,7 +122,7 @@ namespace eval ::scobj::tpg261 {
         }
         }
 
-        proc add_tpg261 {name IP port {filename "noFile"} {
+        proc add_tpg261 {name IP port {filename "noFile"}} {
         if {[SplitReply [environment_simulation]]=="false"} {
             makesctcontroller sct_tpg261_$name std ${IP}:$port "\r\n"
         }