diff --git a/OOequipment/FunctionGenerator.m b/OOequipment/FunctionGenerator.m
index e804a89..5fa1c3d 100644
--- a/OOequipment/FunctionGenerator.m
+++ b/OOequipment/FunctionGenerator.m
@@ -94,7 +94,7 @@ classdef FunctionGenerator < Equipment
 		function l = getLoad(lin)
 			l = regexp(num2str(lin), '([12]|50|in|mi|ma)', 'match', 'once', 'ignorecase');
 
-			if isempty(u)
+			if isempty(l)
 				error(strcat('Invalid load: ', lin));
 			end