Allen-Bradley 1747-L551 SLC 5/05 Processor Module 16KB

1747-L551 Allen‑Bradley SLC 5/05 Processor Module

Product Introduction

The 1747-L551 processor module from Allen‑Bradley is a powerful SLC 5/05 controller within the SLC 500 series. This module delivers robust processing capabilities for medium to large‑scale automation applications. It supports up to 4096 discrete inputs and outputs, plus 480 analog I/O points, making it suitable for complex control systems.

Furthermore, the 1747-L551 includes built‑in Ethernet and RS‑232 communication ports. These enable seamless integration with HMIs, SCADA systems, and other network devices. Its battery‑backed CMOS RAM ensures program retention during power interruptions. For expanded memory, you can add the 1747-M13 backup memory module, extending capacity to 64K.

Technical Specifications

The 1747-L551 processor offers impressive performance metrics and extensive I/O capabilities. Its fast scan times ensure responsive control in time‑critical applications.

Key technical attributes include:

• Manufacturer: Allen‑Bradley

• Series: SLC 500

• Module Type: SLC 5/05 Processor

• User Memory: 16,000 Words (16 KB), Battery‑Backed RAM

• Backup Memory: Supports 1747-M13 (up to 64K)

• Battery: 1747-BA for memory retention

• Inputs: 4096 (discrete)

• Outputs: 4096 (discrete)

• Analog I/O: 480 points

• I/O Chassis: Up to 3 chassis

• Chassis Module Slots: 30 total (across 3 chassis)

• Program Scan Time: 0.9 ms/K typical

• I/O Scan Time: 0.225 ms typical

• Communication Ports: Ethernet (10/100 Base‑T), RS‑232

• Supported Protocols: Ethernet, Remote I/O (RIO), DH485, Data Highway Plus (DH+)

• Real‑Time Clock: Yes (built‑in)

• Programming Support: Online/offline editing, advanced math instructions, indirect addressing

Electrical and Environmental Ratings:

• Ambient Temperature (Operating): 0 to 60°C (32 to 140°F)

• Storage Temperature: -40 to 185°F (-40 to 85°C)

• Relative Humidity: 5 to 95% (non‑condensing)

• Operating Shock: 30G (3 pulses, 11 ms)

• Non‑operating Shock: 50G (3 pulses, 11 ms)

• Operating Vibration: 2.5G at 5 to 2000 Hz

• Non‑operating Vibration: 5G at 5 to 2000 Hz

• Isolation (Backplane to I/O): 1500V AC

• Isolation (Communication Circuits): 500V DC

Communication Capabilities

The 1747-L551 excels in connectivity, offering multiple communication channels for diverse applications. Its built‑in Ethernet port supports 10/100 Base‑T networking with SNMP, BOOTP, and extended messaging. This enables high‑speed data exchange with plant‑wide networks.

The RS‑232 port supports DF1 full‑duplex, DF1 half‑duplex master, and DF1 radio modem protocols. This flexibility allows peer‑to‑peer communication with various devices. Additionally, the 1747-L551 supports Remote I/O (RIO) protocol through communication adapters, enabling distributed I/O installations away from the main chassis.

For DH485 and Data Highway Plus (DH+) networks, you can add compatible communication modules. These protocols expand connectivity options for legacy systems and third‑party devices.

Installation and Mounting Guidelines

The 1747-L551 processor must be installed exclusively in Slot Zero (0) of the SLC 500 chassis. This fixed position ensures proper backplane communication with all I/O modules in the system.

First, power down the entire chassis before inserting or removing the processor. Next, align the module with the chassis guides and slide it firmly into Slot 0. Secure it with the retaining screws to prevent accidental dislodging.

For Remote I/O installations, install a communication adapter in the local chassis and scanner modules in remote chassis. This configuration extends I/O capabilities beyond the local chassis while maintaining centralized control.

Important Safety Note: Always disconnect power from the controller and all I/O devices before installing or uninstalling modules. This prevents electrical shock and equipment damage.

LED Indicators and Diagnostics

The 1747-L551 features multiple LED indicators that provide real‑time status information. These lights help you quickly diagnose system conditions without additional tools.

LED Status Indicators:

• RUN: Indicates the processor is executing the user program

• FAULT: Illuminates when the CPU detects a major error

• BATTERY: Warns when the 1747-BA battery voltage is low

• FORCE: Shows that I/O forces are active

• Ethernet/RS‑232 Activity: Flashes during communication

Understanding these indicators simplifies troubleshooting. For example, a flashing FAULT LED requires immediate attention, while a steady BATTERY LED signals it is time to replace the battery.

Memory and Data Retention

The 1747-L551 uses battery‑backed CMOS RAM to retain user programs and data. The standard memory holds 16,000 words, sufficient for many applications. For larger programs, you can install the 1747-M13 memory module, expanding backup capacity to 64K.

The 1747-BA battery maintains memory during power outages. Under normal conditions, battery life typically exceeds one year. Replace the battery periodically to avoid data loss. Always replace the battery while the processor is powered on to preserve memory contents.

Packaging and Shipping

Your order for the 1747-L551 processor module includes the following items in the package:

• One Allen‑Bradley 1747-L551 SLC 5/05 processor module

• Anti‑static protective packaging

We ship all orders through trusted global carriers to ensure safe and timely delivery. Specifically, our shipping partners include:

• FedEx

• UPS

• DHL

Please note that the package does not include the 1747-BA battery, 1747-M13 memory module, mounting hardware, or programming software. Additionally, certificates of conformity and warranty documents are not included with this listing. For bulk orders or expedited shipping, please contact our sales team.

Frequently Asked Questions (FAQ)

Q1: What memory modules work with the 1747-L551 processor?
A1: This processor supports the 1747-M13 backup memory module, which expands memory capacity to 64K. It also uses the 1747-BA battery for RAM retention.

Q2: Can the 1747-L551 communicate with DH+ networks?
A2: Yes, the 1747-L551 supports Data Highway Plus (DH+) through compatible communication modules.

Q3: What is the maximum number of I/O points this processor supports?
A3: The 1747-L551 supports up to 4096 discrete inputs and 4096 discrete outputs, plus 480 analog I/O points.

Q4: How do I replace the battery on the 1747-L551?
A4: Replace the 1747-BA battery while the processor is powered on. This prevents memory loss. Refer to the user manual for detailed steps.

Q5: Is this processor compatible with ControlLogix or CompactLogix systems?
A5: No, the 1747-L551 is designed exclusively for SLC 500 systems. It does not interface directly with Logix‑family controllers.