diff --git a/site_ansto/motor_dmc2280.c b/site_ansto/motor_dmc2280.c
index 60fde224..cecf9a09 100644
--- a/site_ansto/motor_dmc2280.c
+++ b/site_ansto/motor_dmc2280.c
@@ -43,7 +43,7 @@ int readRS232TillTerm(prs232 self, /*@out@*/void *data, int *datalen);
 #endif
 void KillRS232(/*@only@*/ void *pData);
 /* Storage returned by Tcl_GetVar2 is owned by the Tcl interpreter and should not be modified */
-/*@observer@*//*@dependent@*/ char *Tcl_GetVar2(Tcl_Interp *interp, char *name1, char *name2, int flags);
+/*@observer@*//*@dependent@*/ const char *Tcl_GetVar2(Tcl_Interp *interp, const char *name1, const char *name2, int flags);
 /* The pointer to the Tcl interpreter is owned by SICS and should not be modified */
 /*@observer@*//*@dependent@*/  Tcl_Interp *InterpGetTcl(SicsInterp *pSics);
 /*@+incondefs@*/