Allen-Bradley 1747-SDN/D DeviceNet Scanner Module

The Allen-Bradley 1747-SDN/D, also cataloged as the 1747-SDN/D DeviceNet Scanner Module, serves as the primary SLC 500 DeviceNet Scanner Module utilized to execute deterministic DeviceNet node scanning and I/O data exchange across SLC 500 backplane systems. It provides communication bridging between SLC processor memory structures (M0/M1 files) and up to 63 DeviceNet devices using CAN-based cyclic and event-driven messaging.

Hardware Specifications

Suffix Breakdown & Model Matrix

• 1747: SLC 500 chassis family identifier

• SDN: Scanner DeviceNet Network interface function

• /D: Revision D hardware and firmware generation with enhanced diagnostics and stability updates

No additional functional sub-variants are defined within the provided dataset.

DeviceNet Deterministic Scan Engine and Diagnostic Architecture (Allen-Bradley SLC 500)

The 1747-SDN/D operates a DeviceNet scan engine integrated into the SLC 500 backplane, executing scheduled and unscheduled CAN-based communication across up to 63 nodes. The scanner maps device data into M0/M1 memory structures, where scanlists define polling sequence, data width, and I/O mapping behavior.

Revision D introduces enhanced diagnostic layering, including numeric fault code reporting in addition to LED status indicators for module, network, and I/O states. This enables direct hardware-level fault localization without external software interrogation.

The module supports cyclic, polled, change-of-state (COS), and explicit messaging modes, allowing mixed deterministic and event-triggered data exchange across DeviceNet topology. Firmware updates via ControlFlash utility extend compatibility with updated SLC 500 software environments while maintaining scanlist integrity during configuration cycles.

Frequently Asked Questions (FAQ)

Q: Does the 1747-SDN/D support mixed messaging types simultaneously?
A: Yes. Cyclic, polled, COS, and explicit messaging can coexist within the same scanlist configuration depending on node capability.

Q: What happens if DeviceNet node addressing exceeds 63 devices?
A: The scanner cannot assign or poll addresses beyond 63 nodes; excess devices remain unscanned and are excluded from M0/M1 mapping.

Q: Is firmware upgrade possible while the module is installed in a live chassis?
A: Firmware upgrade requires system-controlled update procedures; scan execution is suspended during ControlFlash operations to prevent memory corruption.

Field Installation Guidelines

• Install into any valid SLC 500 chassis slot; avoid processor-reserved slot constraints.

• Ensure stable 5 VDC backplane supply before insertion or removal.

• Use approved DeviceNet trunk cable with correct termination resistors at both network ends.

• Maintain shield continuity and single-point grounding for CAN noise suppression.

• Configure scanlist parameters using RSNetWorx prior to system commissioning.

• Verify LED and numeric display status codes during initial power-up sequence before enabling I/O scan operation.