The PB7700 power bus is invaluable for saving installation time and wiring when connecting a 24V dc power source to a number of barriers. Typical applications include hazardous-area switches, 4/20mA transmitters and proximity detectors. The diagram illustrates the configuration for 4 barriers but up to 40 barriers can be served by this method. The MTL7798 power feed module would normally be used with standard barriers such as MTL7787+ and MTL7787P+ because the current/voltage trip protection mechanism of the MTL7798 protects
the fuses in the barriers. The MTL7799 dummy barrier can be used instead of the MTL7798 for
direct ‘feed-through’ connection of a 24V dc supply onto the power bus. Looping the power feed to each end of the bussed power allows the removal of individual barriers without loss of power to others in the chain.
Other units that can use the power bus facility: