Product Details
Overview
The 1785-LT2 from Allen-Bradley is a high-performance processor module within the PLC-5 Classic series, designed for versatile industrial control applications. It supports extensive local and remote I/O configurations and provides embedded communication channels including Data Highway Plus (DH+) and RS-232. This module is mounted in the left-most slot of a 1771 I/O chassis and delivers reliable control for medium-to-large automation systems.
Technical Specifications
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Manufacturer: Allen-Bradley
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Product Line: PLC-5 Classic
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Part Number: 1785-LT2
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Module Type: Processor
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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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Total I/O Capacity: 512 inputs / 512 outputs (expandable with modules)
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Maximum Total I/O: 3072 points (any mix)
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Analog I/O: Up to 3072 points
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Embedded RAM: 6K Words (expandable to 14K Words)
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Memory Modules Supported: 1785-MR (4K RAM), 1785-MS (8K RAM), 1785-MJ (8K EEPROM)
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Battery: 1770-XY
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Program Scan Time: 2 ms per K words (bit logic), 8 ms per K words (typical)
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Built-in Communication: One DH+ channel, one local/remote I/O scanner adapter
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Hardware Addressing: 2-slot, 1-slot, ½ slot
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Control Coprocessor Expansion: Supported
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RS-232-C/422-A/423-A Ports: 1
Performance & Communication
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I/O Scan Time per Rack:
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10 ms @ 57.6 kbits/s
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7 ms @ 115.2 kbits/s
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3 ms @ 230.4 kbits/s
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Maximum I/O Chassis Total: 93
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Max Extended Local Chassis: 0
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Max Universal Remote Chassis: 32 per I/O Link
Installation & Mounting
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Location: Left-most slot in 1771 I/O chassis
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Module Keying: Between 40–42 and 54–56
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Weight: 3.06 lbs (1.39 kg)
Applications
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Industrial automation requiring scalable I/O control
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Medium to large PLC-5 system integration
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Remote I/O management with high-speed DH+ communication
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Analog and digital I/O intensive processes
FAQ
Q: Can 1785-LT2 support remote I/O racks?
A: Yes, up to 3 remote racks are supported.
Q: What memory expansion options are available?
A: Supports 4K, 8K RAM modules (1785-MR, 1785-MS) and 8K EEPROM (1785-MJ).
Q: What communication channels are built-in?
A: Includes one DH+ port and one local/remote I/O scanner adapter.
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
Master Acceptance Testing: Understanding FAT and SAT in Industrial Control Systems
Factory Acceptance Testing (FAT) and Site Acceptance Testing (SAT) serve as critical quality assurance gateways in complex industrial control systems. Both procedures verify that programmable logic controllers (PLCs), distributed control systems (DCS), and associated field devices meet strict functional specifications. However, executing these tests effectively requires clear delineation between off-site staging and final field commissioning.
Industrial Networking Essentials: Demystifying Hubs, Switches, and Routers in Control Systems
Industrial automation relies heavily on robust networking infrastructure to connect programmable logic controllers (PLCs), distributed control systems (DCS), and human-machine interfaces (HMIs). Modern factory automation environments generate vast amounts of real-time operational data across deterministic networks. Understanding the structural differences between hubs, switches, and routers ensures optimal traffic segmentation, minimizes latency, and maintains high network availability.
Safety Relays in Industrial Automation: Fundamentals, Design Standards, and Fail-Safe Architecture
Safety relays form the bedrock of functional safety in modern factory automation, preventing catastrophic equipment failure and protecting plant personnel. While standard electromechanical relays handle basic load switching, they lack the redundant diagnostics required for high-risk industrial environments. Modern industrial automation platforms—including programmable logic controllers (PLCs) and distributed control systems (DCS)—rely on specialized safety relays to monitor field devices and isolate hazards instantly.