diff --git a/script/optics/PhotonFluxSpectrum.py b/script/optics/PhotonFluxSpectrum.py
index 8cd9dd5c..e124b143 100644
--- a/script/optics/PhotonFluxSpectrum.py
+++ b/script/optics/PhotonFluxSpectrum.py
@@ -35,10 +35,7 @@ elif RANGE == "C K-edge":
     LATENCY = 1.0
     DWELL = 1.0
 
-KEI_DIODE = "X03DA-KEITHLEY-1:"
-KEI_RMU = "X03DA-KEITHLEY-2:"
-
-prepare_keithleys(DWELL)
+prepare_keithleys(DWELL, True)
 
 if BEAM == "G600 1x1":
     # G600 1x1 reference sscan_2268 (elog:119)