diff --git a/site_ansto/hardsup/sct_rfamp.c b/site_ansto/hardsup/sct_rfamp.c
index 7f2d39ca..aaead6ae 100644
--- a/site_ansto/hardsup/sct_rfamp.c
+++ b/site_ansto/hardsup/sct_rfamp.c
@@ -270,7 +270,7 @@ int RFAmpReading (Ascon *a)
             heat = opstate & 0x01;
             snprintf(replyStr, 128, "address=%c|type=%c|curr=%s|freq=%s|voltage=%s|K3=%d|K2=%d|K1=%d|O=%d|CC=%d|CV=%d|H=%d", \
                 address, ctype, curr, freq, voltage, K3, K2, K1, outOn, CC, CV, heat);
-            DynStringClear(a->wrBuffer);
+            DynStringClear(a->rdBuffer);
             if (0 == DynStringConcatBytes(a->rdBuffer, replyStr, 128)) {
               strcpy(errMsg, "ANSRFAMP: DynStringReplace failed:");
               errNum = ENOMEM;