PRODUCT INFORMATION
Product Overview
The Allen-Bradley 1785-KA is a PLC-5 communication adapter module designed for industrial networking applications. It bridges PLC-5 controllers on Data Highway Plus networks with redistribution points on Data Highway networks. The unit mounts directly into a single slot of an Allen-Bradley 1771 I/O chassis. It draws operating power directly from the backplane and requires no external power source.
This adapter supports communication rates of 57.6 kbps across both Data Highway and Data Highway Plus networks. Up to four modules can operate within a single control architecture. Internal switch assemblies configure network node addressing and baud rate parameters. Diagnostic status LEDs provide real-time channel activity verification during operation.
TECHNICAL DATA
Technical Specifications
| Parameter | Specification |
|---|
| Category | PLCs |
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| Product Line | PLC 5 |
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| Weight | 1.94 lbs (0.88 kg) |
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| Module Type | Communication Adaptor Module |
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| Required Backplane | 1.4 Amperes at 5 Volts DC |
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| Interface Ports | Data Highway, Data Highway Plus, and Allen Bradley Industrial Terminal (Series 1784) |
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| Operation | Process Messages |
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| Communication w/ PLC Processor | Direct Connection to Channel 3 of PLC-5 Processor |
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| LEDs | 1 Diagnosis/Status Per Channel |
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| Max Modules Per System | 4 |
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| Coating | Conformal Coat |
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| Required External Power | None |
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| Typical AC Signal Delay (Off) | 29 (+/- 8) ms |
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| Typical DC Signal Delay (Off) | 30 (+/- 7) ms |
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| Wiring Arm | 1771-WN |
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TECHNICAL INFORMATION
Features
- Connects PLC-5 systems on Data Highway Plus to Data Highway network nodes.
- Installs directly into a single slot of any standard 1771 I/O chassis.
- Operates without external power supplies by drawing current from the chassis backplane.
- Includes six hardware switch assemblies for communication rate selection and node address assignment.
- Provides individual diagnostic status LEDs for each communication channel.
- Supports direct connection to Channel 3 of compatible PLC-5 processors.
TECHNICAL INFORMATION
Applications
- Legacy PLC-5 control systems communicating across multi-tier industrial plant networks.
- Interfacing Data Highway Plus subnets with plant-wide Allen-Bradley Data Highway trunklines.
- Connecting 1784 Series programming terminals to PLC-5 network nodes.
TECHNICAL INFORMATION
Connections / Interfaces
- Side 15-pin male EIA D-shell connector provides communication access to the Data Highway.
- Three-screw terminal block connects to the Data Highway Plus network cable.
- Nine-pin male EIA D-shell connector interfaces with Allen-Bradley 1784 Series industrial terminals.
- Rear backplane connector provides electrical interface to the 1771 chassis.
TECHNICAL INFORMATION
Installation Guidelines
- Insert the module into a single slot of an Allen-Bradley 1771 I/O chassis.
- Position chassis keying bands between pins 4 and 6, and pins 24 and 26.
- Verify the chassis power supply can supply up to 1.5 A at 5 V DC.
- Secure wiring connections before restoring power to the 1771 chassis backplane.
TECHNICAL INFORMATION
Configuration Guidelines
- Set switch SW1 to configure transmission rates on Data Highway and Data Highway Plus.
- Switches SW2 and SW3 are designated for future use and retain standard settings.
- Configure switches SW4, SW5, and SW6 to define network redistribution node addresses.
TECHNICAL INFORMATION
Compatibility
- Allen-Bradley 1771 series I/O chassis.
- Allen-Bradley PLC-5 controllers utilizing Channel 3 communication links.
- Allen-Bradley 1784-T50 and compatible 1784 Series industrial terminals.
TECHNICAL RESOURCES
Documentation
COMPATIBILITY
Compatibility & Replacement
COMPATIBLE MODELSAllen-Bradley 1771 series I/O chassis. Allen-Bradley PLC-5 controllers utilizing Channel 3 communication links. Allen-Bradley 1784-T50 and compatible 1784 Series industrial terminals.
Verify compatibility against the exact Part Number, revision and manufacturer documentation before ordering.
PART VERIFICATION
Before You Order
Industrial automation parts can share similar model names, suffixes and revisions. Confirm the complete manufacturer Part Number before purchase.
01Check Part NumberMatch the complete ordering code on the existing unit.
02Confirm RevisionCheck suffix, hardware or firmware when applicable.
03Send a Label PhotoWe can review a clear label photo when identification is uncertain.
ORDERING PROCESS
From RFQ to Dispatch
1Submit Part Number2Verify Product Identity3Confirm Stock & Condition4Issue Quotation5Dispatch & Tracking
PRODUCT FAQ
Frequently Asked Questions
What is the primary function of the Allen-Bradley 1785-KA?
The module connects PLC-5 controllers on Data Highway Plus to redistribution nodes on Data Highway.
What power source does the 1785-KA require?
It requires no external power and draws 1.4 A to 1.5 A at 5 V DC from the backplane.
What is the market reference price for the 1785-KA?
Observed market reference pricing is approximately $248.00 USD for refurbished condition. Final pricing depends on stock, condition, and quotation terms.
