Allen Bradley 1785-KA DH/DH+ Communication Adapter

Product Overview

The Allen-Bradley 1785-KA is a communication adapter module for PLC-5 systems. It connects Data Highway Plus (DH+) networks to the original Allen-Bradley Data Highway network, enabling communication between PLC-5 processors and legacy PLC-2 and PLC-3 devices on existing Data Highway installations.

Technical Specs

• Function: DH+ to Data Highway communication bridge
• Network 1: Data Highway Plus (DH+)
• Network 2: Data Highway (DH)
• Mounting: 1771 I/O chassis slot (except slot 0)
• Platform: PLC-5 / 1771 I/O
• Compatibility: PLC-5/10, /12, /15, /25, /30, /40, /60, /250 processors

Key Features

• Bridges DH+ and legacy Data Highway networks
• Enables PLC-5 communication with PLC-2 and PLC-3 processors
• Message routing between network nodes
• Installs in standard 1771 I/O chassis

FAQ

• What is the difference between 1785-KA and 1785-KA5? The 1785-KA bridges DH+ to Data Highway; the 1785-KA5 bridges DH+ to DH485 (SLC 500 networks).
• Which slot does it install in? Any slot except slot 0 (leftmost) of the 1771 I/O chassis.
• Is it still supported? The 1785-KA is a legacy module available through surplus channels for maintaining existing installations.

Installation Guide

1. Power down the 1771 I/O chassis.
2. Install the module in any slot except slot 0.
3. Connect the DH+ port to the Data Highway Plus network using 1770-CD cable.
4. Connect the DH port to the Data Highway network.
5. Configure network addresses and verify communication with remote nodes.

Selection Tips

• Select 1785-KA for connecting PLC-5 systems to legacy Data Highway networks.
• For DH485 (SLC 500) connectivity, choose the 1785-KA5 instead.
• Verify existing network infrastructure before ordering; both networks must be operational.