diff --git a/src/epics/util/lib/Filt.pm b/src/epics/util/lib/Filt.pm
index 815fefa0dde7301836ddbeea32d35a47acdf8fb2..52dcb44f2746ab88149bdc079b8933f6cefbf7fa 100644
--- a/src/epics/util/lib/Filt.pm
+++ b/src/epics/util/lib/Filt.pm
@@ -80,6 +80,13 @@ sub frontEndCode {
 	my ($i) = @_;
         my $calcExp = "// FILTER MODULE";
         if ($::ppFIR[$i] == 1) {
+
+            if ( $::modelrate ne 2 and $::modelrate ne 4 )
+            {
+                die ("Error - The model has a FIR filter in it but has a rate of " . $::modelrate .
+                    "K, only 2K and 4K models support FIR filters.");
+            }
+
            $calcExp .= " (PolyPhase FIR)";
         }
         $calcExp .= ":  $::xpartName[$i]\n";