Description

The Allen-Bradley 1753-L32BBBM-8A is a safety-related programmable logic controller within the GuardPLC 1800 series, featuring integrated safety digital, analog, and high-speed counter inputs, digital outputs, and embedded communication interfaces. Designed for fail-safe CPU applications meeting IEC 61508 (SIL 3) and ISO 13849-1 (PLe/Cat. 4) standards, the unit processes safety-critical signals while continuously monitoring execution timing and hardware/software self-tests. The controller integrates four 10/100BaseT RJ-45 Ethernet ports via an internal switch for safety-rated peer-to-peer networking, EtherNet/IP communications, and programming. Non-safety serial communications are supported through RS-485 interfaces, including Modbus RTU Slave on COMM1 and GuardPLC ASCII/High-Speed Safety Protocol (HSP) on COMM3.

Features

• Integrated on-board safety I/O including 24 digital inputs, 8 digital outputs, 8 safety-related analog inputs, and 2 high-speed counters.
• Four 10/100BaseT RJ-45 Ethernet ports operating through an internal Ethernet switch with auto-crossing detection for full- and half-duplex communication.
• Integrated serial communication ports supporting Modbus RTU Slave protocol (COMM1) and GuardPLC ASCII/HSP protocols (COMM3).
• Dual safety certification compliance for SIL 3 according to IEC 61508 and PLe/Cat. 4 according to ISO 13849-1.
• Automated fault detection handling for permanent and transient I/O faults, directing channels or modules to a defined safe state (value 0 / de-energized).
• Recessed hardware reset pushbutton for temporarily restoring default IP addresses, system resource settings, and login credentials.

Applications

• Safety-instrumented systems (SIS) and emergency shutdown applications requiring SIL 3 / PLe Cat. 4 integrity.
• Industrial safety control environments utilizing distributed safety I/O and peer-to-peer Ethernet networks.
• Automation systems requiring combined digital, analog, and high-speed counter processing in a single safety unit.
• Integrated safety systems requiring Modbus RTU Slave or HSP communication with external scanners and controllers.

Technical Specifications

Connections/Interfaces

Installation Guidelines

• Mounting Orientation: Mount the controller horizontally to a zinc-plated yellow-chromate steel DIN rail to ensure effective cooling and continuous grounding.
• Clearance Requirements: Provide a clearance gap of at least 100 mm (3.94 in.) above and below the device and at least 20 mm (0.79 in.) horizontally between devices.
• Ventilation: Ensure air flows freely around the unit, avoid blocking side ventilation slots, and do not mount directly above heating elements.
• Wire Duct Spacing: Wire ducts located in the clearance area must not exceed a depth of 40 mm (1.58 in.); if deeper than 40 mm, mount devices on stand-offs matching the duct depth or maintain an 80 mm (3.15 in.) gap.
• Network Wiring: Use either straight-through or cross-over Ethernet cables for RJ-45 ports; ensure network loops are prevented so data packets reach nodes via a single path.