Product Overview

The Allen-Bradley 1785-L60B is a high-performance central processing unit belonging to the iconic PLC-5® Classic family. Engineered for large-scale industrial control, this processor provides a substantial 64K words of user memory, allowing it to manage complex logic, extensive data tables, and high-density I/O configurations. It is designed to be the primary intelligence in a 1771 Universal I/O chassis, offering a proven and reliable solution for manufacturing, automotive, and process control industries.

The 1785-L60B is distinguished by its extensive communication capabilities. It features four built-in Data Highway Plus (DH+) or Remote I/O (RIO) ports, enabling high-speed peer-to-peer data exchange and decentralized control of remote racks. This architecture supports up to 3072 total I/O points (using complementary addressing), making it an ideal core for systems that span large factory floor areas.

Communication and Networking Architecture

The technical design of the 1785-L60B prioritizes network flexibility. Beyond its DH+ and RIO capabilities, it includes a multi-protocol serial port (25-pin D-shell) that supports RS-232, RS-422A, and RS-423A standards. This allow for seamless integration with SCADA systems, HMI terminals, and third-party devices using DF1 protocols.

For system scalability, the processor supports 2-slot, 1-slot, and half-slot addressing modes. This flexibility allows engineers to optimize the I/O density within each of the 93 possible supported chassis. Data integrity is safeguarded through optional EEPROM or UVPROM non-volatile memory modules (such as the 1785-ME series), ensuring that critical logic is retained during extended power outages or battery failures.

Technical Specifications

• Manufacturer: Allen-Bradley (Rockwell Automation)

• Model Number: 1785-L60B

• Series: PLC-5/60 Classic

• User Memory: 64K Words

• Total I/O Capacity: 3072 Max (Standard or Complementary)

• Remote I/O Racks: 24 Racks

• Communication Ports: * 4 x DH+ or Remote I/O (Universal)

• 1 x Serial (RS-232C, RS-422A, RS-423A)

• 2 x Programming Terminal Ports

• Backplane Current Draw: 3.3A @ 5V DC

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

• Vibration/Shock: 2.0g @ 10–500Hz / 30g Operational

• Dimensions: 4.9 x 15.3 x 27.4 cm

• Weight: 1.4 kg

Reliability and Diagnostics

• Integrated Status Monitoring: Front-panel LEDs provide real-time feedback for Battery health (BATT), CPU Mode, Force status, and Network Communication (COMM).

• Robust Hardware: Certified by UL, CSA, CE, and C-TICK, the module is housed in an open-style enclosure designed for optimal heat dissipation.

• Legacy Compatibility: Seamlessly integrates with existing 1771 I/O modules, preserving the investment in established hardware infrastructures.

• Advanced Logic Processing: Supports floating-point math, complex file instructions, and high-speed interrupt tasks for precise process synchronization.