diff --git a/site_ansto/instrument/reflectometer/config/chopper/chopper.tcl b/site_ansto/instrument/reflectometer/config/chopper/chopper.tcl
index 9e531094..3aaabf5f 100644
--- a/site_ansto/instrument/reflectometer/config/chopper/chopper.tcl
+++ b/site_ansto/instrument/reflectometer/config/chopper/chopper.tcl
@@ -52,7 +52,7 @@ if {$sim_mode == "true"} {
 
 ##
 # @brief Return the last known chopper frequency. To get the current frequency you
-# must issue a 'chopperController update' command first.
+# must issue a 'chopperController status' or ::chopper::ready? command first.
   proc ::chopper::get_frequency {} {
     set msg [split [SplitReply [chopperController frequency]] : ]
     if {[lindex $msg 0] == "FAILED"} {