Overview
The Allen-Bradley 1747-L543 is an SLC 5/04 processor module designed for the SLC 500 modular PLC platform. With 64K words of battery-backed user memory, this processor supports distributed I/O topologies and provides reliable performance for medium to large industrial control applications. The 1747-L543 is compatible with RSLogix 500 programming software and integrates seamlessly into legacy and modern Rockwell Automation systems.
Key Features
- 64K words of battery-backed RAM for program and data storage
- Integrated DH+ (Data Highway Plus) and RS-232 serial communication ports
- Supports up to 4096 discrete inputs and 4096 discrete outputs
- Manages up to 480 analog I/O points
- Fast scan time of 0.9 ms/K average with 0.225 ms I/O scan
- Controls up to 3 chassis with 30 total I/O module slots
- Status LEDs for forced I/O, run, CPU fault, RS-232, and DH+ indication
- Supports ladder logic, math, PID, and advanced instruction sets
Technical Specifications
- Catalog Number: 1747-L543
- Processor Type: SLC 5/04 CPU
- Memory: 64K words (60K program/data, 4K data only)
- User Memory: 64,000 words
- Memory Backup: Battery-backed RAM with Flash EPROM
- Max Discrete Inputs: 4096
- Max Discrete Outputs: 4096
- Analog I/O Capacity: 480 points
- Communication Ports: 1 x DH+ (3-wire terminal), 1 x RS-232 (9-pin)
- Program Scan Time: 0.9 ms/K typical
- I/O Scan Time: 0.225 milliseconds
- Bit Execution: 0.37 microseconds
- Backplane Current Draw: 500 mA at 5V DC
- Operating Temperature: 0°C to 60°C
- Operational Shock Rating: 30G
- Max Chassis: 3 with 30 I/O module slots total
- Programming Software: RSLogix 500
Typical Applications
The 1747-L543 excels in medium to large control applications requiring distributed I/O architecture. Common uses include machine control, process automation, material handling, packaging systems, and advanced motion control with PID capabilities. Its modular design allows SLC racks to be positioned near I/O signals, eliminating long cable runs and reducing wiring complexity. The processor also supports Proportional-Integral-Derivative (PID) controls and position control for servo-driven systems.
Compatibility & Replacements
The Allen-Bradley 1747-L543 is a direct fit for SLC 500 chassis and is compatible with all standard SLC 500 I/O modules. It works with RSLogix 500 programming software and integrates with other Rockwell Automation devices via DH+ networking. While the SLC 500 family is discontinued, the 1747-L543 remains widely available in the surplus market and is supported by current versions of RSLogix 500. For newer applications, consider the CompactLogix or ControlLogix series; however, the 1747-L543 remains the preferred choice for maintaining and upgrading legacy SLC 500 systems. Related SLC 5/04 processors include the 1747-L541 (32K memory) and 1747-L542 (48K memory).
