Allen-Bradley 1771-DB/B BASIC Module with RS-232 PRT Ports

Allen-Bradley 1771-DB PLC-5 BASIC Communication Module DH485/RS-232

Product Description

The Allen-Bradley 1771-DB (Part Number: 1771-DB/B) is a versatile BASIC Module designed for the PLC-5 / 1771 I/O platform. It functions as a co-processor that executes independent programs written in the BASIC programming language, allowing for complex data manipulation, mathematical calculations, and specialized communication tasks that would otherwise overtax the primary PLC processor.

The 1771-DB is equipped with multiple communication interfaces, including DH-485 and two configurable serial ports (PRT1/PRT2). This allows the module to act as a sophisticated gateway between the PLC-5 backplane and peripheral devices such as barcode scanners, printers, weigh scales, and ASCII terminals. By offloading serial string handling and custom protocol execution to the 1771-DB, engineers can maintain high scan speeds on the main control logic while achieving seamless integration with third-party industrial hardware.

Technical Specifications

The following specifications detail the hardware and communication capabilities of the 1771-DB:

Key Features

• Independent Processing: Executes BASIC code independently of the PLC scan to handle complex math or string manipulation.

• Multi-Port Communication: Features DH-485 and dual serial ports for simultaneous connection to multiple devices.

• Flexible Protocol Support: Ideal for creating custom ASCII drivers for non-AB hardware like lab instruments or older HMIs.

• Battery-Backed Memory: Ensures program retention during power cycles, with options for permanent EPROM storage.

• Direct Backplane Access: Efficiently reads and writes data to the PLC-5 data table through simple CALL statements in BASIC.

Industrial Application Scenarios

• Third-Party Integration: Interfacing PLC-5 systems with ASCII-based devices like electronic scales or inkjet printers.

• Complex Calculations: Performing high-level floating-point math or statistical analysis outside of the main ladder logic.

• Data Logging: Formatting and transmitting production data to local terminals or logging devices via serial ports.

• Legacy Network Bridging: Utilizing the DH-485 port to connect older SLC 500 devices to a 1771-based architecture.