1769-ASCII Allen-Bradley Communication Interface Module

Product Overview

The 1769-ASCII is a high-performance specialty communication module for Allen-Bradley CompactLogix and MicroLogix 1500 platforms. It features two fully independent, isolated serial channels that enable controllers to interface with ASCII-protocol devices, such as barcode scanners, weigh scales, printers, and vision systems.

By offloading serial string processing from the main CPU, the 1769-ASCII ensures deterministic system performance while providing robust data exchange through its dedicated DB-9 connectors.

Technical Specifications

Diagnostic and Status Indicators

• TX/RX Indicators: Visual confirmation of data transmission and reception.

• FIFO Status: Monitors the internal buffer to prevent data loss.

• Error Flags: Reports FIFO overflow, RX parity errors, and handshake failures.

• New Data Flag: Triggers PLC logic immediately upon receipt of a completed ASCII string.

Installation and System Limits

• Mounting: Standard 1769 bus interface; 35mm DIN rail or panel mounting for high-shock resistance.

• Compatibility: Works with CompactLogix 5370 controllers, 1769-AENTR Ethernet adapters, and MicroLogix 1500 bases.

• Distance Rating: Must be installed within four slots of the system power supply.

• Enclosure: Open-type design; use IP54 or higher rated enclosure to protect against contaminants.

Common Technical Questions

• Does the 1769-ASCII support RS-485 or RS-422?
  No. It is designed for RS-232. For RS-485 or RS-422, use an external signal converter or a specialized module like the 1769-SM2.

• Can I program the module to parse specific string delimiters?
  Yes. You can define start and end characters (e.g., Carriage Return, Line Feed) so the PLC processes only completed data packets, simplifying ladder logic programming.