Allen-Bradley 1769-L20 CompactLogix Processor Module

Overview

The Allen-Bradley 1769-L20 is a high-performance CompactLogix Processor Module designed for small to medium automation systems. As part of the CompactLogix family, it offers powerful processing, flexible connectivity, and compact design, making it ideal for control applications that require reliability and scalability. The 1769-L20 provides both Channel 0 RS-232 and Channel 1 RS-232 ports, enabling smooth serial communication with external devices and monitoring systems.

Engineers value this module for its LED status indicators, which provide real-time feedback on operating and communication conditions. The unit supports up to 8 I/O modules across two I/O banks with a single expansion cable, ensuring flexible system configuration.

Technical Specifications

Parameter	Specification
Manufacturer	Allen-Bradley
Series	CompactLogix
Model Number	1769-L20
Module Type	Processor Module
User Memory	64 KB (including overhead memory)
Communication Ports	2 × RS-232 (Channel 0 for DH-485, Channel 1 for general serial communication)
Backplane Current (5V DC)	600 mA
Backplane Current (24V DC)	0 mA
Supported I/O Modules	Up to 8 modules in 2 banks
Expansion Cable	1 maximum
Battery Type	1747-BA lithium battery (replaceable)
Programming Cable	1747-CP3 or 1756-CP3
Wire Type	Copper, 90°C
Wire Size (Solid)	22–14 AWG
Wire Size (Stranded)	22–16 AWG
Replacement Terminal Block	1769-RTBN18
Operating Temperature	0°C to 60°C (32°F to 140°F)
Storage Temperature	-40°C to 85°C (-40°F to 185°F)
Relative Humidity	5%–95% non-condensing
Operating Vibration	5 g at 10–500 Hz, 0.030 in displacement
Operating Shock (Panel Mount)	30 g at 11 ms
Operating Shock (DIN Rail Mount)	20 g at 11 ms
Non-Operating Shock (Panel/DIN)	40 g / 30 g
Power Supply Voltage	5 V DC
Mounting Options	Panel mount or DIN rail
Enclosure Type	Clean, dry environments

Design and Performance

The 1769-L20 combines compact construction with robust performance. Its efficient design measures 50 × 87 × 118 mm, making it suitable for tight control cabinets. The controller weighs only 0.34 kg (0.75 lbs), ensuring lightweight installation without compromising reliability.

The Channel 0 RS-232 port supports DH-485 communication, while Channel 1 handles general serial connections. Engineers can easily monitor both through dedicated LED indicators, simplifying diagnostics and system maintenance. The 1747-BA lithium battery provides reliable memory backup, securing user programs and system data during power loss.

Reliability and Environmental Ratings

The Allen-Bradley 1769-L20 performs consistently in demanding industrial environments. It withstands vibration levels up to 5 g and shock ratings up to 30 g, maintaining stability during continuous operation. The wide operating temperature range from 0°C to 60°C ensures optimal functionality across diverse applications.