Overview
The Allen-Bradley 1747-L541 is an SLC 500 5/04 central processing unit (CPU) designed for mid-range industrial automation and control applications. Part of the proven SLC 500 modular platform, this processor delivers reliable performance with 16K words of user memory, flash EPROM backup, and fast scan time (0.90 ms/K typical). The unit supports up to 4096 discrete input and output points, making it suitable for distributed I/O architectures and complex control strategies.
Key Features
- Memory: 16K words user memory with battery-backed CMOS RAM and flash EPROM backup
- I/O Capacity: Supports up to 4096 discrete inputs and 4096 outputs, plus up to 480 analog I/O points
- Communication Ports: Built-in DH+ channel (57.6K, 115.2K, 230.4K baud) and RS-232 port
- Protocols: DH+, DF1, DH-485, ASCII, Modbus RTU, and extended messaging capabilities
- Scan Performance: 0.90 ms/K typical execution speed with advanced math instructions
- Distributed Control: DeviceNet pass-through and remote I/O support; can manage local system options across 3 chassis (up to 30 slots)
Technical Specifications
- 16K Program Memory (expandable with optional memory modules)
- 4096 Discrete Input Points
- 4096 Discrete Output Points
- 480 Maximum Analog I/O Points
- Processor Speed: 0.90 ms/K typical
- DH+ Communication: 57.6K, 115.2K, 230.4K baud rates
- RS-232 Serial Port (DF1, DH-485, ASCII, Modbus RTU)
- Operating Temperature: 0 to 60°C (32 to 140°F)
- Power Requirements: 1A at 5V DC, 200mA at 24V DC (from backplane)
- Programming Instructions: 107 standard instructions
- Weight: Approximately 0.3 kg (2 lbs)
Typical Applications
The 1747-L541 is ideal for medium-complexity automation tasks including:
- Manufacturing process control and sequencing
- Machine control with distributed I/O racks
- Material handling and conveyor systems
- HVAC and building automation
- Remote monitoring and data collection via DH+ or RS-232
- Multi-rack systems requiring high-speed inter-processor communication
Compatibility & Replacements
Compatible With
- SLC 500 modular chassis (all sizes)
- 1747-series I/O modules and analog modules
- SLC 500, PLC-2, PLC-5, and ControlLogix processors (via DH+ messaging)
- Allen-Bradley and third-party DeviceNet modules (with pass-through support)
- RSLogix 500 programming software
Replaces / Drop-In Replacement For
The 1747-L541 Series B is a direct replacement for earlier Series A versions. Compatible memory modules include the 1747-M11 and 1747-M13 (Series C OS401 or later) for expanded memory backup up to 64K.
Works With
- RSLogix 500 (Rockwell Automation development environment)
- DH+ protocol (Data Highway Plus) for multi-drop and extended-distance topologies
- DF1 and DH-485 peer-to-peer serial communication
- Modbus RTU and ASCII protocols via RS-232
- Allen-Bradley communication adapters and scanner modules for distributed I/O
