Allen-Bradley 1747-DCM SLC 500 Direct Communication Module

Product Description

The 1747-DCM is a high-speed communication interface designed for the Allen-Bradley SLC 500 platform. This Direct Communication Module allows an SLC 500 chassis to act as a distributed station on a Universal Remote I/O (RIO) network. Unlike standard I/O adapters, the 1747-DCM enables a local SLC processor to communicate directly with a remote master scanner (such as a PLC-5 or a ControlLogix RIO scanner) while simultaneously executing its own local control logic.

By occupying a single slot in the SLC backplane, the 1747-DCM (Ser A/B) facilitates the transfer of discrete and block transfer data between different controller platforms. This makes it an essential component for hybrid automation systems where localized high-speed processing must be coordinated with a centralized supervisory control system.

Detailed Technical Specifications

• Model Number: 1747-DCM

• Brand: Allen-Bradley / Rockwell Automation

• Module Type: Direct Communication / Remote I/O (RIO) Slave

• Communication Rate: 57.6 kbps, 115.2 kbps, or 230.4 kbps

• Backplane Current (5V DC): 360 mA

• Backplane Current (24V DC): 0 mA

• Connection Interface: 3-pin Phoenix terminal for RIO link

• Network Cable: Belden 9463 (Blue Hose)

• Addressing Capacity: Supports 1/4, 1/2, 3/4, or Full Rack addressing

• Maximum Node Capacity: Up to 64 nodes per RIO link (network dependent)

• Isolation: 500V DC (continuous) between RIO link and backplane

• Operating Temperature: 0 to 60 degrees Celsius (32 to 140 degrees Fahrenheit)

• Status Indicators: LED diagnostics for COMM and FAULT status

• Net Weight: 0.21 kg (0.47 lbs)

Industrial Application Scenarios

The 1747-DCM is primarily utilized in large-scale plant migrations or complex multi-tier architectures. For example, it allows an older SLC 500 machine cell to be integrated into a newer PLC-5 or ControlLogix supervisory network without replacing the existing SLC hardware. It is commonly found in automotive body shops, material handling sorters, and water treatment SCADA systems.

Professional FAQ

• Can the 1747-DCM be used in a remote chassis without a processor?

  No. Unlike the 1747-ASB, the 1747-DCM requires a local SLC processor (SLC 5/01, 5/02, 5/03, 5/04, or 5/05) to manage the local I/O and data table exchange.

• Does it support Block Transfer (BTR/BTW)?

  Yes, the 1747-DCM supports block transfers of up to 64 words, allowing for the exchange of complex analog data or floating-point variables between the SLC and the master scanner.