The Allen-Bradley 1746-SDN, also cataloged as the 1746-SDN DeviceNet Scanner Module, operates as a dedicated hardware component for DeviceNet network interface management within SLC 500 system architectures. Occupying a single slot in an SLC 500 chassis, the module bridges backplane communication with external DeviceNet field nodes. It executes continuous I/O data scanning, pass-through message routing, and device status management, interfacing directly with SLC 5/02 or later controllers at network transfer speeds up to 125 Kbps.

Module Configuration & Compatibility Matrix

• 1746: SLC 500 rack-based modular system platform chassis assignment.
• SDN: Single-slot DeviceNet Scanner interface architecture.
• Controller Support: Full backplane compatibility with Allen-Bradley SLC 5/02, 5/03, 5/04, and 5/05 controllers.
• Pass-Through Functionality: Supports direct software passthrough for field device configuration and node parameter monitoring.

System Hardware Specifications

Backplane Transfer & Industrial Network Synchronization

The scanner module maps DeviceNet field node I/O directly into the SLC processor data table via the 1746 backplane bus. By maintaining strict firmware flash compatibility across controller revisions, the unit simplifies network device updates without hardware swaps. The backplane driver architecture facilitates smooth data mapping across EtherNet/IP deterministic networks when bridged through SLC processors, optimizing system I/O density scaling and maintaining low-latency scan rates across all configured network nodes.

Standard Delivery Content

• 1 x Allen-Bradley 1746-SDN DeviceNet Scanner Module
• 1 x 5-Pin Open-Style Pluggable DeviceNet Terminal Connector
• 1 x Printed Installation Instruction Manual

Field Cable Installation & Mounting Guidelines

• Chassis Slot Installation
  • Disconnect power to the SLC 500 chassis before inserting or removing the scanner module from the rack slot.
  • Align the circuit card with the chassis guide rails and push firmly until top and bottom retention latches engage.
• DeviceNet Bus Wiring
  • Connect the 5-wire DeviceNet cable to the front terminal block following standard color-coded signal/power pin assignments.
  • Install 121 Ohm, 1/4 W terminating resistors across the physical ends of the main trunk line to prevent signal reflection.

Frequently Asked Questions

• Which SLC 500 processors are compatible with the 1746-SDN scanner module?

  The module is compatible with Allen-Bradley SLC 5/02, 5/03, 5/04, and 5/05 processors running standard firmware.

• What current draw does the 1746-SDN place on the SLC backplane?

  The module draws 500 mA (0.5 A) directly from the 5 VDC backplane logic power supply rail.

• Does the 1746-SDN support hot-swapping inside an energized chassis?

  No, the SLC 500 backplane architecture requires system power to be OFF before removing or inserting modules.

• Can DeviceNet field devices be configured through the 1746-SDN module?

  Yes, the module supports pass-through messaging, allowing tools like RSNetWorx to configure nodes across the backplane.

• What data transfer rate is supported on the DeviceNet communication port?

  The module supports standard DeviceNet data rates, operating at 125 Kbps for baseline field network communications.

• How are network status and node diagnostic errors displayed on the module?

  The front panel features a two-digit numeric display along with status LEDs for module, network, and node diagnostics.

• Does the 1746-SDN require external power on the DeviceNet port?

  Yes, the DeviceNet network port requires 24 VDC external bus power to operate the network transceiver circuitry.

• What is the storage temperature rating for the 1746-SDN hardware?

  The module is rated for safe storage in ambient temperature environments ranging from -40 to +85 deg C.