Siemens 505-6851-A Remote Base Controller

Siemens PPX:505-6851-A Remote Base Controller is the intelligent interface that links a SIMATIC TI505 controller with remote base I/O in the TI505 Redundant I/O system. It supports addressing up to 2048 I/O points—one local I/O base plus up to 15 remote bases—over shielded twisted-pair wiring, with a controller-to-RBC link distance limited to about 3300 ft and remote bases capable of being up to 6600 ft apart. Front-panel features include base-number selection via a thumbwheel and rotary switch, plus status LEDs and status codes that indicate operation and faults. An RS232 port provides programming/configuration access, and a modem F-connector enables remote connectivity. In dual-RBC configurations within the same base, the RBC on the right becomes the active unit at power-up. The PPX:505-6851-A is designed for use with Series 505 I/O and uses the shielded-twisted-pair link, with reference documentation that documents PPX:505–6851A/B RBCs and their role in the SIMATIC 545/555/575 architecture.