User's Manual

SBS-900 Shore Based Radar Systems
Chapter 10: Corrective maintenance
KH-1602-2 issue 1: Standard SBS900 Systems Operator & Maintenance Handbook
Page 221 of 240
10.8.17 Safety and security switches
Safety switches
The safety switches form part of a safety current I-loop. When either the Antenna Rotation or Man
Aloft switches are set to OFF or if the safety current loop is open, single and 3-phase AC supplies to
the transceiver/ gearbox are isolated thereby stopping antenna rotation and system transmission.
Antenna rotation Key switch Man aloft switch
The Antenna Rotation keyswitch is located on
the front door of the RDU.
This switch can be set to OFF and the key
removed and retained by the maintainer.
An externally mounted waterproof masthead
switch.
This switch can be set to FREE or OFF
Safety current loop: Serial connection of normally closed switches.
Polarity Positive Amplitude Fused (500mA anti-surge) +24V
Additional switches: The Antenna Rotation keyswitch and Man Aloft switch are provided as
standard however additional switches can be serially connected as shown: