Allen‑Bradley 1769‑ASCII CompactLogix 2‑Channel ASCII Interface Module

Technical Specifications

Main Features and Advantages

Dual‑Channel Independent Operation with Flexible Media Support

The Allen‑Bradley 1769‑ASCII is equipped with two individually isolated serial channels, each featuring a standard DB‑9 male connector that supports RS‑232, RS‑422, and RS‑485 communication standards . This versatility allows the 1769‑ASCII to interface simultaneously with a diverse array of ASCII devices—for example, connecting a barcode scanner to Port 1 via RS‑232 while communicating with a weigh scale on Port 2 over RS‑485—with both channels operating concurrently and independently at different configurations . The actual communication media is automatically selected based on the wiring connections to the DB‑9 connector, making the configuration process straightforward and transparent to the user . Each serial channel is fully isolated from the backplane and from each other, providing enhanced noise immunity and protection against ground loops in large factory installations where devices may be powered from different electrical sources .

Comprehensive Data Handling with Hardware Handshaking

The 1769‑ASCII supports RTS/CTS hardware handshaking, enabling reliable data flow control when communicating with serial devices that require it . The module provides 256‑byte transmit and receive buffers on each channel, accommodating burst data transmissions and preventing data loss when the controller is processing other tasks . With a configurable baud rate range from 300 to 115,200 bits per second and support for 7 or 8 data bits, various parity options, and 1 or 2 stop bits, the 1769‑ASCII can match virtually any legacy or modern serial device configuration . Serial port status monitoring is provided through diagnostic flags for TX FIFO overflow, RX FIFO overflow, RX parity errors, handshake errors, and new data flags, allowing the 1769‑ASCII to detect and report communication anomalies that could impact system performance .

Seamless Integration with Rockwell Automation Ecosystem

The 1769‑ASCII is designed for effortless integration into the Rockwell Automation environment, with configuration performed directly through RSLogix 5000 or Studio 5000 Logix Designer software . The module occupies 108 input words and 31 configuration words in the controller’s memory map, providing ample data exchange capacity for complex ASCII message parsing and generation . With a power supply distance rating of four modules, the 1769‑ASCII can be flexibly positioned within the 1769 I/O chassis while maintaining reliable power delivery . The module’s compatibility with both CompactLogix and MicroLogix 1500 platforms means that a single 1769‑ASCII spare can support multiple controller families in a facility, simplifying inventory management and reducing downtime during emergency replacements.

Application Fields

Factory Automation and Production Line Data Capture

The Allen‑Bradley 1769‑ASCII is extensively deployed in manufacturing environments where serial data acquisition from ASCII devices is essential for production tracking and quality control. In automated assembly lines, the 1769‑ASCII interfaces with barcode scanners at multiple stations to capture work‑in‑progress data, part serial numbers, and traceability information, transmitting this data to the CompactLogix controller for real‑time production tracking and integration with manufacturing execution systems . The module’s ability to operate both channels simultaneously with different configurations allows a single 1769‑ASCII to support scanners with different communication requirements on the same production line, reducing hardware costs and simplifying system architecture. In packaging operations, the 1769‑ASCII interfaces with label printers and inkjet coders, enabling the controller to dynamically print product‑specific information such as batch numbers, expiration dates, and regulatory markings based on real‑time production data .