Product Overview

The Allen-Bradley 1785-L30B functions as the central intelligence for the PLC-5/30 control system. This standard processor module executes complex ladder logic programs and manages high-density I/O configurations across the 1771 platform. It integrates multiple communication protocols, including Data Highway Plus (DH+) and Remote I/O, allowing for seamless data exchange between controllers and peripheral devices. With 32K words of static RAM (SRAM) and a robust instruction set, the 1785-L30B provides the computational power required for large-scale, time-critical industrial processes.

Technical Specifications

We offer this unit as 100% Brand New and Factory Sealed, ensuring the highest level of component integrity for your legacy infrastructure.

Engineering Advantages

The 1785-L30B resolves significant operational and architectural challenges in mature automation environments:

• Expanded Network Architecture: Dual DH+/Remote I/O channels allow the processor to function simultaneously as a network node and a scanner. This dual-purpose capability facilitates communication with human-machine interfaces (HMIs) while controlling distributed I/O racks.

• Complex Process Control: The processor supports an advanced instruction set including PID loops and floating-point math. This enables precise regulation of temperature, pressure, and flow in chemical, pharmaceutical, and water treatment applications.

• Hardware-Level Reliability: The 1785-L30B utilizes industrial-grade SRAM with battery backup. This prevents program loss during unexpected power cycles, ensuring the system resumes operation immediately upon power restoration without requiring a manual reload.

• Legacy Continuity: As a direct replacement for older 1785-series processors, the L30B allows plants to maintain existing 1771 I/O investments. It fits directly into any standard 1771 universal I/O chassis, eliminating the need for costly cabinet rewiring or hardware redesign.

FAQs

Does the 1785-L30B support memory expansion?

Yes. You can install an optional EEPROM module to provide non-volatile program storage. This ensures the processor can reload the application automatically if the backup battery fails during a power outage.

Can I use the RS-232 port for peer-to-peer networking?

The RS-232C port typically serves as a programming port or for connection to point-to-point devices like barcode scanners or serial printers. For networking between controllers, use the dedicated DH+ channels.

What is the "Low Battery" indicator's behavior?

The "BATT" LED illuminates when the internal lithium battery voltage drops below a safe threshold. You should replace the battery while the processor is powered up to prevent losing the program currently stored in the SRAM.

Is this processor compatible with all 1771 chassis?

The 1785-L30B must occupy the leftmost slot (Slot 0) of a 1771 universal I/O chassis. It works with all standard 1771-A1B through 1771-A4B chassis assemblies.