When the RadiCentre is turned on buy a beeping sound can be heard it means that the Interlock plug has been tripped. This can be intentionally in the case that the interlock is connected to a safety lock on an EMC chamber door or because due to the Interlock plug not being plugged in.
Plug in the Interlock plug to stop the beeing set the RadiCentre to a state in which the it can be used for testing and measurements.