diff --git a/tangostationcontrol/tangostationcontrol/devices/beam_device.py b/tangostationcontrol/tangostationcontrol/devices/beam_device.py
index 6599661771d5fd224949af494f8fec4466423c37..4072ef384765092c9db8922b698c1834314fa29a 100644
--- a/tangostationcontrol/tangostationcontrol/devices/beam_device.py
+++ b/tangostationcontrol/tangostationcontrol/devices/beam_device.py
@@ -157,6 +157,8 @@ class beam_device(lofar_device):
         # generic delay calculator to ask about validity of settings
         self.generic_delay_calculator = delay_calculator([0, 0, 0])
 
+    # Derived  classes will override this with a non-parameterised
+    # version that lofar_device will call.
     @log_exceptions()
     def configure_for_initialise(self, num_pointings):
         super().configure_for_initialise()