Allen-Bradley 1768-L45S – Compact GuardLogix Safety Controller with SIL 3 and PL e

The Allen-Bradley 1768-L45S is a Compact GuardLogix controller. Specifically, this controller features a 1oo2 safety architecture. It is rated up to Safety Integrity Level 3 (SIL 3) and Performance Level e (PL e). Furthermore, it provides 3 MB of standard memory and 1 MB of dedicated safety memory. In addition, it supports up to 30 I/O modules across 3 banks. Consequently, this safety controller suits demanding safety applications requiring high integrity and performance.

Ordering Configuration and Product Identification

• Brand: Allen-Bradley / Rockwell Automation.

• Part Number: 1768-L45S.

• Product Line: Compact GuardLogix.

• Module Type: Processor Module (Safety Controller).

• Safety Architecture: 1oo2 (one-out-of-two) architecture.

• Safety Rating: SIL 3 (IEC 61508).

• Performance Level: PL e (ISO 13849-1).

• Standard Memory: 3 MB.

• Safety Memory: 1 MB.

• Total Memory: 4 MB.

• Enclosure: Open style.

• Dimensions: 131.6 x 90 x 121.8 mm (5.18 x 3.55 x 4.80 in.).

• Shipping Weight: 0.45 kg (15.9 oz).

• Shipping Dimensions: 8 x 8 x 5 inches.

• Therefore, the Allen-Bradley 1768-L45S offers robust safety capabilities for critical applications.

Memory and Storage Specifications

• Standard Memory: 3 MB allocated for standard control tasks.

• Safety Memory: 1 MB allocated for safety tasks.

• Memory Card: 1784-CF128 CompactFlash card supported.

• Standard Programming Languages: IEC 61131-3 compliant (ladder, structured text, function block, SFC).

• Safety Programming Language: Relay ladder only (with safety application instructions).

• Functionality: Standard automation and safety tasks run concurrently.

• Application: Process or machine automation with integrated safety.

• Thus, the 1768-L45S separates standard and safety memory for integrity.

I/O Capacity and Expansion

• Local I/O Modules (1768): Up to 4 modules supported.

• Expansion I/O Modules (1769 Compact I/O): Up to 30 modules supported.

• Expansion Banks: Up to 3 expansion I/O banks.

• Total I/O Modules: Up to 30 modules total.

• Communication Modules (1768): Up to 2 modules supported.

• Flexibility: Mix of local and expansion I/O.

• Scalability: Suitable for small to medium safety applications.

• Consequently, the Allen-Bradley 1768-L45S scales to meet application requirements.

Communication and Networking

• Embedded RS232 Port: Yes, integrated.

• RS232 Isolation: Tested at 500V DC for 6 seconds.

• RS232 Baud Rate: 38.4 Kbps maximum.

• Supported Communication Modules: Ethernet/IP (standard and safety), ControlNet (standard and safety), DeviceNet.

• Safety Communication: Supported over Ethernet/IP and ControlNet.

• Standard Communication: Supported over all module types.

• Flexibility: Choose communication modules based on network requirements.

• Therefore, the 1768-L45S integrates into various industrial networks.

Power Specifications

• Backplane Current: 2.1 Amps at 24 Volts DC.

• Power Consumption: 50.4 Watts.

• Power Dissipation: 9.5 Watts.

• Isolation Voltage: 30 Volts continuous.

• Isolation Type: Functional insulation.

• Isolation Test: RS-232 ports tested at 500V DC for 6 seconds.

• Power Supply: External 24V DC required.

• Thus, the 1768-L45S requires substantial backplane power for operation.

Temperature and Environmental Ratings

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

• Non-operating Temperature: -40°C to 85°C (-40°F to 185°F).

• Relative Humidity: 5% to 95% non-condensing.

• Operating Vibration: 5G at 10 to 500 Hz.

• Operating Shock: 30G.

• Non-operating Shock: 50G.

• Mounting Clearance (Top/Bottom): 105 mm (4.13 inches).

• Mounting Clearance (Left/Right): 90 mm (3.54 inches).

• Cooling: Natural convection (climate control devices optional).

• Enclosure: Open style (requires installation in cabinet).

• Moreover, the Allen-Bradley 1768-L45S withstands typical industrial conditions.

Safety Features and Architecture

• Safety Architecture: 1oo2 (one-out-of-two) redundant architecture.

• Safety Integrity Level: SIL 3 per IEC 61508.

• Performance Level: PL e per ISO 13849-1.

• Safety Task: Dedicated safety task with watchdog.

• Safety Programming: Relay ladder only with safety instructions.

• Safety Communication: Supported over Ethernet/IP and ControlNet.

• Redundancy: Dual-processor architecture for fault tolerance.

• Diagnostics: Comprehensive self-testing and monitoring.

• Consequently, the 1768-L45S provides high-integrity safety for critical applications.

Mounting and Installation

• Mounting Methods: Panel mount or DIN rail.

• Mounting Clearance (Top/Bottom): 105 mm (4.13 inches) minimum.

• Mounting Clearance (Left/Right): 90 mm (3.54 inches) minimum.

• Purpose of Clearance: Adequate airflow for cooling.

• Cooling: Natural convection recommended.

• Optional Devices: Heaters or fans for extreme environments.

• Installation Orientation: Horizontal preferred.

• Enclosure: Must be installed in a control cabinet.

• Thus, proper clearance is essential for reliable operation.

Installation Guide

First, verify that all power sources are completely disconnected. Then, select either panel mount or DIN rail mount for the Allen-Bradley 1768-L45S. For DIN rail, clip the controller onto the rail firmly. For panel mount, use appropriate screws. After that, ensure clearances of 105 mm (4.13 inches) top and bottom and 90 mm (3.54 inches) left and right. Then, connect the 24V DC power supply to the controller. The backplane current draw is 2.1 Amps. Then, install up to 4 local 1768 I/O modules and up to 30 1769 Compact I/O modules across 3 banks. For safety applications, install communication modules such as Ethernet/IP safety or ControlNet safety. Then, insert the 1784-CF128 CompactFlash card for memory backup if needed. Then, apply power to the controller. The processor will perform its power-up sequence. For standard tasks, program using IEC 61131-3 languages. For safety tasks, use relay ladder with safety application instructions. Then, download your program to the controller. Finally, test all safety functions and standard I/O connections thoroughly. As a result, the Allen-Bradley 1768-L45S will provide reliable safety control.

Packaging List

• One Allen-Bradley 1768-L45S Compact GuardLogix controller

• One product identification label

• One installation and configuration guide

• One safety documentation sheet

• Mounting hardware (panel or DIN rail, per order)

Common FAQs

Q1: What safety rating does the Allen-Bradley 1768-L45S provide?
A: This controller is rated up to SIL 3 per IEC 61508. It also provides PL e per ISO 13849-1. Therefore, it suits the highest safety integrity level applications.

Q2: How much memory does the 1768-L45S have?
A: This controller provides 3 MB of standard memory. Additionally, it provides 1 MB of dedicated safety memory. Therefore, total memory is 4 MB for combined standard and safety applications.

Q3: What I/O expansion does the Allen-Bradley 1768-L45S support?
A: It supports up to 4 local 1768 I/O modules. It also supports up to 30 1769 Compact I/O modules. These are distributed across up to 3 expansion banks. Up to 2 communication modules are also supported.

Q4: What programming languages are available for the 1768-L45S?
A: Standard tasks can be programmed using IEC 61131-3 languages. Safety tasks may only be programmed using relay ladder language. Safety application instructions are required for safety logic. Therefore, safety programming is restricted to ladder for integrity.

Q5: What are the mounting requirements for the Allen-Bradley 1768-L45S?
A: Mounting clearances of 105 mm (4.13 inches) top and bottom are required. Clearances of 90 mm (3.54 inches) left and right are also required. Therefore, adequate airflow is essential for maintaining the 0-60°C operating temperature.