diff --git a/tcl/fibre.stick b/tcl/fibre.stick
index 489cdd1..3be9854 100644
--- a/tcl/fibre.stick
+++ b/tcl/fibre.stick
@@ -1,3 +1,3 @@
 stickDesc = optical fibre stick
 
-stick_sensors x68258 none
+stick_sensors x68258 undefined
diff --git a/tcl/thermalcond.stick b/tcl/thermalcond.stick
index 10d014f..ae88cfd 100644
--- a/tcl/thermalcond.stick
+++ b/tcl/thermalcond.stick
@@ -1,6 +1,6 @@
 stickDesc = 50 mm thermal conductivity stick, version with standard lsc370 driver
 
-stick_sensors x00290 none
+stick_sensors x00290 undefined
 
 makenv res -driver 370_lsc {
   lsc_sensor s1 -channel 1 -sensor x00444  -excitation 200uV