diff --git a/site_ansto/instrument/reflectometer/config/chopper/sct_chopper.tcl b/site_ansto/instrument/reflectometer/config/chopper/sct_chopper.tcl
index 9267599b..f1758ef0 100644
--- a/site_ansto/instrument/reflectometer/config/chopper/sct_chopper.tcl
+++ b/site_ansto/instrument/reflectometer/config/chopper/sct_chopper.tcl
@@ -223,7 +223,7 @@ proc rdPwdAck {} {
     hsetprop $chopperPath/$datPar sdsinfo ::nexus::scobj::sdsinfo
   }
   foreach param {ch1speed ch2speed ch3speed ch4speed} {
-    mkChopperDatPar $chopperPath $param "aspeed"
+    mkChopperDatPar $chopperPath $param "rspeed"
   }
   foreach param {ch1phase ch2phase ch3phase ch4phase} {
     mkChopperDatPar $chopperPath $param "rphase"