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Allen-Bradley

Allen-Bradley 1785-LT3 PLC-5/12 Processor Module

SKU 1785-LT3

In stock

12-month warranty
Free returns within 30 days

Manufacturer: Allen-Bradley
Product No.: 1785-LT3
Origin United States
Product Type: Prosessor Module
Barcode: 8537101190
Payment: T/T, Western Union
Weight: 1.337 kg
Dimensions: 34 mm x 315 mm x 198 mm (W x H x D)
Shipping port: Xiamen
Warranty: 12 months

Product Description

The 1785-LT3 is a PLC-5/12 Processor Module engineered to direct sequential control, automated processing operations, and comprehensive factory-floor data handling. This slot-mounted hardware component installs into the left-most slot of a standard 1771 I/O chassis, executing specialized ladder logic programs to manage complex system variables. Functioning as a standalone and adapter-capable device on industrial networks, the 1785-LT3 coordinates multi-node signals and diagnostic data via built-in physical connection interfaces.

Features

Seamless interlocking architecture designed exclusively for insertion into standard 1771 I/O chassis frames
Integrated rear switch assembly (SW1) enabling direct manual assignment of the physical station address
Multiple front-facing LED diagnostics providing continuous real-time verification of operational, communication, and battery conditions
Dedicated logic capabilities that execute bit-level instructions, advanced math functions, and automated runtime troubleshooting

Applications

Sequential manufacturing control networks
Machine-level diagnostic and execution systems
Distributed data acquisition nodes
Distributed control architecture utilizing peer-to-peer communication

Technical Specifications

Parameter	Specification
Manufacturer	Allen-Bradley
Catalog Number	1785-LT3
Processor Model	PLC-5/12
Product Line	Classic PLC-5
Module Type	Processor Module
Memory Capacity	6 K words
Maximum Local Racks Supported	4 (1 resident chassis)
Maximum Remote Racks Supported	None
I/O Capacity (8-point modules)	128 I/O
I/O Capacity (16-point modules)	256 I/O
I/O Capacity (32-point modules)	512 I/O
Program Scan Time (Bit Logic)	2 ms/K words
Program Scan Time (Typical)	8 ms/K words
Backplane Current Load	2.5 A
Communication Modes	Standalone, Adapter
Network Interfaces	DH+ (Data Highway Plus)
Optional Memory Modules	8K EEPROM (1785-MJ)
Battery Type	1770-XY lithium battery (or 3.6V AA Tadiran TL-5104 AEL/S)
Hardware Addressing Support	2-slot, 1-slot, 1/2-slot
Supported I/O Modules	Bulletin 1771 I/O (8, 16, 32-point, and intelligent modules)
Module Location Slot	1771 I/O chassis, left-most slot
Keying Band Positions	Between 40 and 42, Between 54 and 56
Time of Day Clock (Max Variation at 60 degC)	Plus or minus 3 min per month
Time of Day Clock (Typical Variation at 20 degC)	Plus or minus 20 s per month
Timing Accuracy	One program scan
Typical Discrete Local I/O Scan	1 ms per local I/O rack
Weight	1337 g (42.15 oz.)
Operating Temperature	0 to 60 degC (32 to 140 degF)
Storage Temperature	-40 to 85 degC (-40 to 185 degF)
Relative Humidity	5 to 95% (without condensation)
Operating/Non-operating Vibration	1 g @ 10 to 500 Hz (0.012 inches peak-to-peak displacement)
Operating Shock	30 g peak acceleration for 11 plus or minus 1 ms duration
Non-operating Shock	50 g peak acceleration for 11 plus or minus 1 ms duration

Connections/Interfaces

Connector Pin / Switch	Function / Assignment
SW1 Switch Assembly	Establishes the physical DH+ Station Address for Channel 1A
Battery Connector	Built-in side connector mating to the 1770-XY battery pressure terminals
Memory Module Slot	Front-accessible receiver accepting the optional 1785-MJ 8K EEPROM
CP Cable Connector	Mating port interfaces directly with the industrial programming terminal cable

Installation Guidelines

Chassis Positioning: Always install the processor module into the dedicated, left-most slot of the 1771 I/O backplane chassis to ensure proper logic termination.
Keying Band Fitment: Position the hardware keying bands securely within the backplane rails between slots 40 and 42, and between slots 54 and 56 to verify correct module insertion.
Isolation Warning: Turn off all electrical supplies feeding the local I/O chassis or memory socket before mounting the hardware or sliding an EEPROM into the slot to eliminate major diagnostic faults or data corruption.
Ground Infrastructure: Bond a dedicated grounding electrode conductor from the I/O chassis enclosure wall star washer directly to the main plant earth ground bus to minimize industrial EMI.

Compliance and Certifications

CSA certified
CSA Class I, Division 2, Groups A, B, C, D
UL listed

Shipping & Returns

Global Express Shipping

Standard Delivery: 4–6 business days via DHL, FedEx, and UPS.
Express Dispatch: Same-day dispatch for in-stock orders placed before 2:00 PM (GMT+8).
Worldwide Coverage: Serving over 150 countries.

Returns & Warranty

30-Day Guarantee: Returns accepted for in-stock products in original, factory-sealed packaging.
12-Month Warranty: Every industrial component is backed by our technical warranty.

FAQ

What is the backplane power requirement for this device?

The module requires a backplane current draw of 2.5A from the local chassis power supply assembly.

Which specific slots must be keyed for this hardware installation?

The mechanical keying bands must be placed between positions 40 and 42, and between positions 54 and 56 within the chassis.

What is the maximum program memory limit of the processor module?

The device contains a fixed internal memory capacity of 6K words to hold user applications and program instructions.

What happens if a memory module is handled while the system has power?

Inserting or removing the EEPROM module while power is applied can cause a complete loss of program memory and trigger a permanent processor major fault.

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