Description

Brief Product Description

The Allen-Bradley 1785-L20E is an enhanced PLC-5 processor featuring integrated Ethernet connectivity and 16K words of SRAM memory. This single-slot CPU manages medium-scale industrial automation tasks by supporting up to 512 local and remote I/O points.

Advanced Processing Power for PLC-5 Systems

The Allen-Bradley 1785-L20E provides essential control logic for the proven PLC-5 platform, specifically catering to medium-range automation architectures. This single-slot CPU module integrates seamlessly into 1771-series chassis, including the A1B, A2B, and A4B models. By supporting a total of 512 I/O points, the processor enables precise management of complex field devices across various data formats such as floating-point, integer, and string variables. Consequently, this controller remains a vital component for facilities maintaining legacy infrastructure while requiring modern communication capabilities.

Integrated Ethernet and Multi-Protocol Connectivity

Communication flexibility distinguishes the 1785-L20E from standard processors in its class. This module features a built-in Ethernet port supporting 10/100 Mbps transmission, which facilitates high-speed data exchange with HMI systems and upper-level enterprise networks. Furthermore, the controller includes dedicated ports for DH+ and Remote I/O (RIO), alongside a versatile serial interface compatible with RS-232, RS-422A, and RS-423 standards. These multiple interfaces allow the CPU to manage up to 12 remote I/O racks in addition to its local chassis, ensuring extensive scalability for expanding production lines.

Reliable Memory Management and Industrial Durability

Reliability remains at the forefront of the 1785-L20E design, which utilizes 16K words of volatile SRAM backed by a 1785-XYC lithium battery. This battery backup preserves critical program data during total power loss, while optional non-volatile EEPROM modules, such as the 1785-ME series, provide secondary layers of security. In terms of performance, the processor achieves rapid I/O scan times as low as 3 milliseconds at 230.4 kbps. Moreover, the hardware withstands extreme industrial conditions, including operating temperatures up to 140°F and mechanical shocks up to 30G, ensuring continuous operation in high-vibration environments.

Key Technical Characteristics

• Ethernet Integration: Onboard 10/100 Mbps Ethernet port for seamless network connectivity.
• Scalable I/O Support: Controls up to 512 I/O points across 13 total chassis (1 local, 12 remote).
• Memory Protection: 16K words of SRAM with lithium battery backup and optional EEPROM expansion.
• High-Speed Execution: Optimized scan times for mission-critical logic and high-speed data processing.
• Industrial Hardening: Certified for high-vibration environments with a 30G shock resistance rating.
• Comprehensive Certifications: Fully compliant with UL, CSA, and CE standards for global industrial use.

Technical Specifications