diff --git a/kat_test/random/lock-cav1.kat b/kat_test/random/lock-cav1.kat
index a909dd358b43a7a73ce20fe95515f1adcf5e5f72..0fda02c6c2b26a748aa1457d7f91c084cb436e3e 100644
--- a/kat_test/random/lock-cav1.kat
+++ b/kat_test/random/lock-cav1.kat
@@ -35,8 +35,8 @@ time                            # print computation time
 # The resulting plot contains only the feedback
 # signal of the control loop.
 
-pd1 pdh 40k 0 n1                # diode for PDH signal
-noplot pdh                      # do not plot this output
+pd1 pdh 40k 0 n1_2                # diode for PDH signal
+noplot pdh                       # do not plot this output
 
 # define error signal 'err'= Re(photo diode output)
 set err pdh re