diff --git a/site_ansto/hardsup/Digital/params.c b/site_ansto/hardsup/Digital/params.c
index 3de94f94..2a225aa3 100644
--- a/site_ansto/hardsup/Digital/params.c
+++ b/site_ansto/hardsup/Digital/params.c
@@ -187,7 +187,7 @@ bool param_set(pPARAMETERS pp, char* name, char* value)
       pp->source = strtol(value, NULL, 10);
       if (pp->source < 1)
         pp->source = 0;
-      else if (pp->source > 1000)
+      else if (pp->source > 3)
         pp->source = 0;
       dbg_printf(0, "=>%d\n", pp->source);
       break;