Description

The Allen-Bradley 1747-L553 is an SLC 5/05 modular processor unit designed for medium-to-large programmable logic controller (PLC) applications within the 1746 SLC system architecture. Featuring 64 KB of user memory, this high-capacity controller executes ladder logic and communication routines, offering execution times as fast as 0.37 µs for bit instructions and a typical program scan time of 0.9 ms per kilobyte. The processor installs directly into slot 0 (the leftmost position) of any standard 1746 chassis, interfacing with up to 3 local chassis and managing up to 30 slots.

Equipped with dual integrated communication ports, the 1747-L553 provides Channel 1 Ethernet TCP/IP connectivity along with a Channel 0 RS-232 serial interface. Channel 1 allows seamless plant-floor networking via standard 10Base-T Ethernet cabling, enabling high-speed peer-to-peer messaging, data acquisition, and programming connection through network hubs. Channel 0 supports versatile point-to-point and multi-drop serial configurations, including DF1 Full-Duplex, DF1 Half-Duplex master/slave, DH-485, and ASCII protocols.

The module includes integrated RAM backed up by a replaceable lithium battery (Catalog Number 1747-BA), which preserves volatile program data during power loss. An internal capacitor maintains power to the RAM for at least 30 minutes during a battery swap, preventing program corruption. For permanent, non-volatile storage, the processor supports optional Flash EPROM memory modules.

Features

• 64 KB User Memory: Provides expanded capacity for complex ladder programming, data storage, and status file tracking.
• High-Speed Logic Execution: Achieves 0.37 µs bit execution time (XIC) and a program scan time of 0.9 ms/K.
• Integrated Ethernet Channel: Channel 1 features 10Base-T Ethernet TCP/IP communication for high-speed network integration.
• Multiprotocol Serial Channel: Channel 0 RS-232 port supports DF1 Full-Duplex, DF1 Half-Duplex, DH-485, and ASCII protocols.
• Large I/O System Capacity: Supports up to 4096 discrete inputs and 4096 discrete outputs across a 3-chassis local system (up to 30 total slots).
• Diagnostic Status LEDs: Front-panel LEDs provide clear status indication for Power, Run, Fault (FLT), Battery (BATT), Force, Ethernet (ENET), and RS232 channels.
• 30-Minute Backup Capacitor: Keeps RAM energized for at least 30 minutes during battery maintenance without loss of system data.

Applications

• Automated Assembly & Material Handling: Manages multi-axis sequencing, conveyor lines, and high-speed data transfer to supervisory systems over Ethernet.
• Process Control Systems: Handles discrete and analog loops across multiple chassis setups with up to 4,096 discrete I/O points.
• Remote Monitoring & Control: Utilizes standard TCP/IP networking to communicate with plant-wide SCADA and HMI platforms.
• Legacy System Upgrades: Replaces smaller 16 KB or 32 KB SLC 5/05 processors (such as 1747-L551 or 1747-L552) to expand ladder program capacity without hardware re-engineering.

Technical Specifications

Connections / Interfaces

Installation Guidelines

1. Safety Verification: Ensure power to the 1746 chassis power supply is completely switched OFF before inserting or removing the processor.
2. Electrostatic Precautions: Handle the controller by its plastic housing to avoid static discharge, which can damage onboard electronics or clear RAM memory.
3. Chassis Insertion: Slide the processor into Slot 0 (the far-left slot) of the 1746 chassis until the top and bottom retainer clips snap securely in place.
4. Protective Wrap: Remove the protective shipping wrap from the module housing after physical installation into the chassis.
5. Power-On Verification: Turn on the chassis power supply (1746-P1 through 1746-P7 series). Confirm that the power supply POWER LED illuminates and the controller FLT (Fault) LED flashes initially.

Configuration and Maintenance Guidelines

Initial Network Configuration

1. Connect a 1747-CP3 serial cable between Channel 0 of the processor and your computer's COM port.
2. Open RSLogix 500 and configure DF1 Full-Duplex serial driver defaults (19.2K baud, no parity, CRC error check).
3. Assign the required static IP address, subnet mask, and gateway settings to Channel 1 (Ethernet) over the RS-232 serial connection.
4. Connect Channel 1 to your 10Base-T Ethernet network hub or switch to enable high-speed ladder upload/download and network messaging.

Battery Maintenance

• Low Battery Warning: Replace the lithium battery (Cat. No. 1747-BA) when the red BATT LED illuminates on the front panel.
• RAM Backup Hold Time: An onboard capacitor holds memory intact for at least 30 minutes after the battery is disconnected.
• Replacement Procedure: Turn off power, release the chassis clips, slide out the processor, unplug the old battery connector from its socket, clip the new 1747-BA battery in place, plug in the connector, and re-install the processor in slot 0.

Compliance and Certifications

• UL Listed
• CSA Approved
• Class 1, Groups A, B, C, or D, Division 2 Hazardous Locations
• CE Compliant (all applicable directives)