Product Details
Overview
The Allen-Bradley 1785-L20E is a PLC-5/20E Processor Module designed for reliable control and communication within industrial automation environments. As part of the Allen-Bradley PLC-5 family, it provides Ethernet connectivity, advanced memory management, and flexible I/O configuration options, making it suitable for mid-scale automation systems requiring dependable networked control.
Built to withstand harsh operating conditions, the 1785-L20E integrates robust communication ports, high-speed processing, and wide environmental tolerance for demanding manufacturing and process control applications.
Technical Specifications
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Manufacturer: Allen-Bradley (Rockwell Automation)
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Product Line: PLC-5 Series
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Part Number: 1785-L20E
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Processor Type: PLC-5/20E
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Product Type: Programmable Logic Controller Module
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Memory Capacity: 16 Kwords of user memory
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Non-Volatile Backup: Supported with EEPROM modules (1785-ME16, 1785-ME32, 1785-ME64, 1785-M100)
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Battery Type: 1770-XYC, for memory retention
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Protected Memory: Not available
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Total I/O Capacity: 512 I/O points (any mix) or 512 inputs + 512 outputs in complementary mode
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Analog I/O Capacity: Up to 512 points
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I/O Chassis Support: Up to 13 total; 12 remote I/O chassis supported
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Local I/O Racks: Maximum of 4 (addresses 0–3)
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I/O Scan Time per Rack: 10 ms @ 57.6 kbps, 7 ms @ 115.2 kbps, 3 ms @ 230.4 kbps
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Embedded Communication Ports:
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1 x DH+ (fixed)
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1 x DH+/Remote I/O (adapter or scanner)
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1 x Serial port (configurable for RS-232, RS-423, or RS-422A)
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1 x Ethernet interface
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Backplane Current Load: 2.3 A
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Power Dissipation: 12 W typical
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Recommended Power Supplies: 1771-P4S, 1771-P6S, 1771-P4S1, 1771-P6S1
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Control Co-Processor Port: Supported
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Operating Temperature: 0°C to +60°C (32°F to 140°F)
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Storage Temperature: -40°C to +85°C (-40°F to 185°F)
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Humidity: 5% to 95%, non-condensing
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Weight: 3.13 lbs (1.42 kg)
Key Features
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Ethernet-Enabled Control: Integrates Ethernet communication for seamless network connectivity.
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Flexible I/O Management: Supports up to 512 digital and analog I/O channels for scalable automation.
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Durable Architecture: Complies with IEC 60068 environmental testing standards for temperature and shock resistance.
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Comprehensive Communication: Includes DH+, Remote I/O, and multi-protocol serial interfaces.
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Reliable Memory Retention: Battery-backed static RAM and optional EEPROM storage ensure data preservation.
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Compatible Power Options: Works with multiple 1771-series power supplies for design flexibility.
Applications
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Process control systems in manufacturing plants
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Industrial machinery automation
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Material handling systems
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Distributed control networks using ControlNet or Ethernet/IP
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Retrofit and maintenance of legacy Allen-Bradley PLC-5 installations
FAQ
Q: What is the memory capacity of the 1785-L20E processor?
A: It features 16 Kwords of user memory, expandable with external EEPROM modules.
Q: Can this processor communicate over Ethernet?
A: Yes, it has a built-in Ethernet interface in addition to DH+, Remote I/O, and serial communication ports.
Q: Which power supplies are compatible with this module?
A: It supports 1771-P4S, 1771-P6S, 1771-P4S1, and 1771-P6S1 units.
Q: Does it support ControlNet?
A: No, this model supports Ethernet and DH+ networks, not ControlNet.
Additional Information
- 100% Genuine Parts: All products are original and authentic, ensuring reliable industrial performance.
- 30-Day Refund Guarantee: Return any in-stock item within 30 days in original, unopened packaging for a full refund (excluding shipping and fees).
- 12-Month Warranty: Covers defects in materials or workmanship; excludes misuse, normal wear, or unauthorized modifications.
- Worldwide Shipping: We ship via USPS, UPS, FedEx, and DHL. Delivery times vary by country and may be subject to customs or import fees.
- Support & Contact: Technical and warranty assistance is available anytime. Contact us here: Contact.
- Purchase Guidance: Check product specifications and compatibility carefully before ordering to ensure proper application.
Tech & Buying Guide
Engineering MCC Signal Interface Terminations in Modern Process Automation
Industrial manufacturing plants rely on Motor Control Centers (MCC) to drive critical electrical loads. Plant engineers must interface these MCC motor starters and drives with central control systems. Standardizing the Signal Interface Termination (SIT) architecture ensures seamless command delivery and feedback monitoring between field equipment and process automation platforms.
Layer-2 vs. Layer-3 Network Switches in Industrial Control Systems
Modern factory automation relies heavily on robust Industrial Ethernet communications. Control system engineers deploy managed Ethernet switches to connect programmable logic controllers (PLCs), distributed control systems (DCS), human-machine interfaces (HMIs), and field I/O devices. Selecting between Layer-2 and Layer-3 switching architecture directly impacts network throughput, routing capabilities, and overall cybersecurity defense in operational technology (OT) networks.
Understanding OpenTelemetry in Industrial Automation: Architecture, Observability, and Operational Benefits
Modern industrial control systems (PLCs, DCS, edge nodes) are rapidly adopting cloud-native architectures, generating vast operational data. OpenTelemetry offers an open-source framework that unifies metrics, logs, and execution traces, enabling standardized observability across industrial automation and IT systems.