Product Details
Overview
The Allen-Bradley 1785-LT is a high-performance PLC-5/15 processor module designed for the Classic PLC-5 series. It provides fast logic execution and supports both local and remote I/O expansion, delivering reliable performance for complex industrial control systems. The module is engineered for durability and long-term operation in harsh industrial environments.
Technical Specifications
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Model Number: 1785-LT
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Brand / Series: Allen-Bradley PLC-5
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Module Type: Processor Module
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Weight: 3.06 lbs (1.39 kg)
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Embedded RAM: 6K Words, expandable up to 14K Words
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Memory Expansion Modules: 4K RAM (1785-MR), 8K RAM (1785-MS), 8K EEPROM (1785-MJ)
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Battery: 1770-XY
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Program Scan Time: 2 ms/K words (bit logic), 8 ms/K words typical
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Supported Local I/O: Up to 4 racks (1 resident rack)
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Supported Remote I/O: Up to 3 remote racks
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I/O Capacity: 512 inputs + 512 outputs using 16 or 32-pt modules
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Max Total I/O: 3072 (any mix) or 3072 in + 3072 out (complementary)
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Analog I/O Capacity: 512, Max Analog I/O: 3072
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DH+ Channel: Yes
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Remote I/O Channel: Yes
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Hardware Addressing: 2-slot, 1-slot, ½ slot
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Module Location: 1771-I/O chassis, left-most slot
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Keying: Between 40–42; Between 54–56
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I/O Scan Time Per Rack: 10 ms @ 57.6 kbits/s, 7 ms @ 115.2 kbits/s, 3 ms @ 230.4 kbits/s
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Max I/O Chassis Total: 93
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Max I/O Chassis Extended Local: 0
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Max I/O Chassis Universal Remote: 32 max per I/O link
Key Features
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High-Speed Processing: Optimized 6K Words SRAM with up to 14K expansion for large programs.
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Comprehensive I/O Support: Supports local and remote I/O expansion with up to 3072 points.
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Built-In Communication: DH+ and standalone scanner for local/remote I/O ensures seamless integration.
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Flexible Memory Options: Supports RAM and EEPROM modules for data retention and program storage.
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Industrial Durability: Designed for 1771-I/O chassis with long-term stability in industrial environments.
Applications
The 1785-LT is suitable for:
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Manufacturing automation and process control
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Data acquisition and SCADA systems
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Large-scale PLC networks with multiple local and remote racks
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Critical industrial applications requiring high-speed I/O processing
Similar Models
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1785-LP – Smaller memory PLC-5/10 module, lower I/O capacity.
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1785-LT – Standard PLC-5/15 processor with 6K SRAM, expandable up to 14K.
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1785-LX – High-capacity PLC-5/20 processor module for extended I/O and memory requirements.
FAQ
Q: How many I/O points can the 1785-LT module manage?
A: It can handle up to 512 inputs and 512 outputs per module, with a maximum total I/O of 3072.
Q: Can the embedded RAM be expanded?
A: Yes, the 6K Words SRAM can expand up to 14K Words using memory modules.
Q: What chassis does this module fit into?
A: It is designed for the 1771-I/O chassis, occupying the left-most slot.
Q: Does it support remote I/O?
A: Yes, it can interface with up to 3 remote racks via DH+ channels.
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.