Allen-Bradley 1747-L542 SLC 500 SLC 5/04 Processor Module

The Allen-Bradley 1747-L542 is a modular programmable logic controller processor unit belonging to the SLC 500 system family. Operating as an SLC 5/04 processor, this device executes user-defined control logic programs, services system I/O modules, and manages multi-node communications across automated industrial environments. The unit features built-in Data Highway Plus (DH+) and configurable RS-232 communication channels, enabling direct integration into supervisory control systems, distributed networks, and operator interface terminals.

Designed for installation in slot 0 of a standard 1746 modular chassis, the 1747-L542 provides high-speed bit execution, expansive I/O addressing capacity, and non-volatile memory backup capabilities. The processor continuously executes an operating cycle consisting of input scanning, program execution, output updating, communication servicing, and overhead processing to maintain precise system control.

Key Features

• 32 K words user-configurable memory capacity for program and data file storage
• Integrated Data Highway Plus (DH+) Channel 1 communication port supporting high-speed peer-to-peer messaging
• Configurable RS-232 Channel 0 port supporting DF1 Full-Duplex, DF1 Half-Duplex, DH-485, ASCII, DF1 Radio Modem, and Modbus RTU Master protocols
• Hardware keyswitch providing RUN, PROGRAM (PROG), and REMOTE (REM) mode selection
• Front-panel status LEDs for monitoring power, CPU fault, battery status, forced I/O, and communication activity
• Support for optional Flash EPROM memory backup modules (1747-M13)
• High-speed instruction execution rate of 0.37 us for basic XIC bit instructions

Typical Applications

• Factory automation and machine control systems
• SCADA remote terminal unit (RTU) stations and data acquisition
• Material handling and conveyor systems
• Process control and distributed PLC networks using Data Highway Plus (DH+)
• Pumping stations and water/wastewater treatment monitoring

Technical Specifications

Installation Guidelines

• Chassis Mounting: Mount the processor exclusively into the leftmost slot (Slot 0) of an SLC 500 1746 chassis. Ensure system power is disconnected before insertion or removal.
• Enclosure and Cooling: Install the modular system inside a suitably rated NEMA/IP enclosure located in a Pollution Degree 2 industrial environment. Maintain at least 10.2 cm (4 in.) of clearance around the chassis for proper convection airflow and cable bend radius.
• Grounding: Ensure the 1746 chassis is solidly grounded to the enclosure backpanel using copper braid or 5.2 mm2 (10 AWG) copper wire connected to a central ground bus.
• Battery Backup: Verify that the backup lithium battery (Catalog Number 1747-BA) is connected to the motherboard before inserting the processor module into the chassis to retain RAM memory during power loss.
• Wiring and Communication Cables: Route communication lines (DH+ blue hose and RS-232 serial cables) away from high-voltage power wiring and noise-generating inductive loads.

Compliance and Certifications

• UL Listed Industrial Control Equipment
• C-UL Listed Industrial Control Equipment for use in Canada
• UL Listed Industrial Control Equipment for use in Class I, Division 2, Hazardous Locations Groups A, B, C, or D
• CE compliant for all applicable directives (EMC Directive 89/336/EEC and Low Voltage Directive 73/23/EEC)
• C-Tick marked for all applicable acts