Product Overview
In safety-critical manufacturing environments, the Allen-Bradley 1768-L45S CompactGuardLogix controller delivers robust performance and reliable safety functionality. This processor module integrates standard CompactLogix capabilities with an embedded safety architecture, making it a dependable choice for machinery and process automation that demands up to Safety Integrity Level 3 (SIL 3) and Performance Level e (PL e).
The 1768-L45S uses a 1oo2 safety architecture and provides 3 MB of standard memory for control tasks plus 1 MB of dedicated safety memory. It supports up to thirty I/O modules distributed across three expansion banks, allowing flexible system scaling. With its compact design and open enclosure, the 1768-L45S suits panel or DIN rail mounting in industrial control cabinets.
Technical Specifications
Key specifications of the Allen-Bradley 1768-L45S include:
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Backplane Current: 2.1 Amps at 24 Volts
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Isolation Voltage: 30 Volts Continuous
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Power Consumption: 50.4 Watts
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Power Dissipation: 9.5 Watts
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Memory: 3 MB standard, 1 MB safety
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Local I/O Modules: 4 (1768 I/O)
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Expansion I/O Modules: Up to 30 (1769 Compact I/O)
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Expansion Banks: Up to 3
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Dimensions: 131.6 x 90 x 121.8 mm (5.18 x 3.55 x 4.80 in.)
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Shipping Weight: 0.45 kg (15.9 oz)
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Operating Temperature: 0–60 °C
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Non-Operating Temperature: -40–85 °C
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Relative Humidity: 5–95%
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Operating Vibration: 5g at 10–500 Hz
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Operating Shock: 30g
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Non-Operating Shock: 50g
Performance and Safety Architecture
The 1768-L45S implements a 1oo2 safety architecture, ensuring high availability and fail-safe operation. It meets SIL 3 and PL e requirements, making it suitable for applications where personnel safety and machine protection are paramount. The dedicated 1 MB safety memory ensures that safety tasks run independently from standard control logic, reducing the risk of interference.
Standard control programs can be developed using IEC 61131-3 languages, while safety tasks must be programmed in relay ladder logic with safety application instructions. This separation simplifies certification and maintenance.
Compatibility and Integration
The Allen-Bradley 1768-L45S supports a variety of communication modules, including EtherNet/IP (standard and safety), ControlNet (standard and safety), and DeviceNet. This flexibility allows seamless integration into existing Rockwell Automation architectures and mixed-vendor environments. The controller also features an embedded RS232 interface for local programming and diagnostics.
For I/O expansion, the 1768-L45S supports up to four local 1768 I/O modules and up to thirty remote 1769 Compact I/O modules across three expansion banks. This scalability makes it ideal for applications ranging from standalone machines to distributed control systems.
Installation and Mounting
The 1768-L45S can be mounted on a DIN rail or directly to a panel. Proper clearance is essential for airflow: maintain at least 105 mm (4.13 in.) above and below the controller, and 90 mm (3.54 in.) on both sides. Operating temperature range is 0–60 °C, so ensure adequate ventilation or use climate control devices such as heaters or fans in enclosed cabinets.
Maintenance and Reliability
Routine inspection of the 1768-L45S should focus on ensuring clean, dust-free air vents and secure mounting. The controller's robust design withstands vibration up to 5g and shock up to 30g during operation, reducing the likelihood of failures in harsh industrial environments. Periodic checks of the backplane connections and communication cables help prevent intermittent faults.
Given the safety-critical nature of the controller, regular functional testing of safety circuits is recommended to verify continued compliance with SIL 3 and PL e standards.
Selection Guide
When selecting the Allen-Bradley 1768-L45S, verify your system's memory and I/O requirements. The 3 MB standard memory handles most medium-complexity applications, while the 1 MB safety memory supports extensive safety logic. Confirm the number of I/O modules and expansion banks needed for your process.
PLC Source PRO provides genuine Allen-Bradley 1768-L45S controllers and related components, ensuring compatibility and reliability for your automation projects.