Description

The Allen-Bradley 1747-L541 is an SLC 5/04 modular processor designed for medium-scale industrial control and distributed I/O applications. As a core central processing unit within the Allen-Bradley SLC 500 system architecture, it delivers high-speed program execution and expanded communication integration across industrial networks.

The controller features 12K words of user program memory and up to 4K words of additional data storage. Equipped with an on-board math co-processor, the 1747-L541 achieves execution times of 0.37 $\mu$s for bit instructions (XIC) and a typical scan time of 0.9 ms per 1K of ladder logic. It supports advanced instruction sets, indirect addressing, remote I/O, and DeviceNet pass-through, enabling efficient control logic for complex automation tasks.

Networking features include an integrated Data Highway Plus (DH+) port for direct connection to peer-to-peer DH+ networks, allowing direct communication with PLC-5 processors without additional interface modules. Additionally, an RS-232 serial communication port supports user-configurable protocols, including DF1 Full-Duplex, DF1 Half-Duplex master/slave, DF1 Radio Modem, DH-485, Modbus RTU, and ASCII.

Features

• 16K Total Memory Architecture: Configured with 12K words of ladder program memory and up to 4K words of data storage.
• On-Board Math Co-Processor: Accelerates execution of advanced floating-point and math instructions.
• Built-in DH+ Communication Port: Enables high-speed multi-drop and extended distance peer-to-peer networking directly to DH+ devices and PLC-5 systems.
• Multi-Protocol RS-232 Port: Configurable for DF1, DH-485, ASCII, and DF1 radio modem communication.
• High System Expansion: Supports up to 960 local discrete I/O points across a maximum local system footprint of 3 chassis and 30 slots.
• Fast Processing Speed: Provides a typical scan time of 0.9 ms/K and bit execution speed of 0.37 $\mu$s.
• Distributed System Integration: Supports distributed I/O configurations using remote I/O scanners and direct communication modules.

Applications

• Distributed Factory Automation: Controls complex machinery and distributed production lines using DH+ peer-to-peer networking.
• Process Machinery Control: Executes real-time PID loops and mathematical algorithms via the integrated hardware math co-processor.
• System Upgrades & Maintenance: Serves as a direct drop-in replacement processor for existing SLC 5/04 hardware chassis configurations.
• Multi-Node Plant Networking: Connects local SLC 500 racks to plant-wide supervisory networks and operator interfaces.

Technical Specifications

Connections / Interfaces

Installation Guidelines

1. Verify system power is off before inserting or removing the processor module from Slot 0 of the 1746 chassis.
2. Confirm backplane power supply capacity (5V DC and 24V DC current limits) accounts for the 1.0 A @ 5V DC and 200 mA @ 24V DC requirements of the module.
3. Ensure proper grounding of the 1746 chassis and continuous shielding on Data Highway Plus (Belden #9463) communication cabling.
4. Set the 3-position keyswitch to REM or PROG before attempting initial firmware updates or logic downloading.
5. Secure all serial and DH+ connectors with locking screws to prevent signal loss from operational vibration.

Configuration Guidelines

1. Open RSLogix 500 software and select 1747-L541 SLC 5/04 CPU in the System Configuration dialog.
2. Configure Channel 1 (DH+) with a unique node address (0-63) and match the network baud rate (typically 57.6k, 115.2k, or 230.4k baud).
3. Set Channel 0 (RS-232) protocol driver to DF1 Full-Duplex, DH-485, or ASCII based on connected target devices.
4. Program user memory partitions and establish data file protection using software security features or hardware keyswitch settings.
5. Download the complete application file, verify runtime memory utilization, and switch the CPU mode to Run.