Allen-Bradley 1753-L28BBBM Programmable Safety Controller

The Allen-Bradley 1753-L28BBBM GuardPLC 1600 Safety Controller is a compact, standalone safety controller designed for safety-critical machine automation in the GuardPLC 1600 family. It provides 20 digital inputs and 8 digital outputs and runs from a 24 V DC supply with a maximum load current of 9 A, supported by 250 KB of user memory for programs and 250 KB of application data memory for safety logic. The unit features continuous isolation of 50 V between I/O, power, and network connections and uses Category 2 wiring on signal and power ports. Communication is via RS-485 ports: COMM1 can function as a Modbus RTU Slave or a Profibus-DP Slave on variants such as 1753-L28BBBM and 1753-L32BBBM-8A, while COMM3 supports GuardPLC ASCII Protocol (read-only) or High-Speed Safety Protocol (HSP) for safety communications. Catalog numbers in this family include 1753-L28BBBM, 1753-L28BBBP, 1753-L32BBBM-8A, and 1753-L32BBBP-8A. Typical applications include implementing emergency-stop responses, safety interlocks, and controlled shutdown sequences within a GuardPLC 1600 safety system and Rockwell Automation safety software ecosystem.