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
Redundant Automation Systems: Ensuring Continuous Uptime in Critical Control Infrastructure
System reliability directly determines operational profitability across high stakes process industries. Modern industrial automation platforms must eliminate single points of failure to prevent catastrophic shutdowns. Deploying fault tolerant architecture safeguards complex facilities against unexpected hardware glitches, network disruptions, and maintenance outages.
Understanding Types of Noise in Electronic Circuits and Control Systems
Signal integrity directly determines measurement accuracy and loop stability across industrial automation environments. Electronic noise introduces unwanted stochastic interference into analog loops, sensor feedback lines, and digital fieldbus networks. Understanding how intrinsic electronic noise and external electromagnetic interference manifest allows control engineers to optimize signal conditioning and shield sensitive instrumentation effectively.
Why 24V DC Power Supplies Standardize Modern Industrial Automation
Industrial control cabinets worldwide rely on 24V DC as the universal power standard for field instrumentation, sensors, and controllers. Walk into any manufacturing plant, and you will find PLCs, human-machine interfaces (HMIs), and smart actuators running on extra-low voltage DC. Standardizing on 24V DC enhances operational safety, lowers cabinet footprint, and maintains steady control performance across factory networks.