Allen-Bradley 1747-SDN/B DeviceNet Scanner Module

The Allen-Bradley 1747-SDN/B, also cataloged as the 1747-SDN/B DeviceNet Scanner Module, serves as the primary SLC 500 DeviceNet Scanner Module utilized to execute cyclic and event-driven DeviceNet node polling across SLC 500 chassis backplane platforms. It provides direct communication bridging between SLC processor memory structures (M0/M1 files) and up to 63 DeviceNet field nodes through CAN-based deterministic messaging.

Hardware Specifications

Suffix Breakdown & Model Matrix

• 1747: SLC 500 chassis family identifier

• SDN: Scanner DeviceNet network interface designation

• /B: Hardware revision B indicating updated firmware and compliance revision level

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

DeviceNet Network Deterministic Communication Architecture (Allen-Bradley SLC 500)

The 1747-SDN/B implements a DeviceNet scanner engine operating over CAN physical layer messaging with scheduled and polled I/O execution. Network configuration is mapped through M0/M1 memory files, where scanlist definitions determine node polling sequence and data exchange structure.

The module performs deterministic multi-node arbitration across up to 63 devices, supporting cyclic I/O, polled messaging, and change-of-state (COS) transmission modes. Backplane integration uses 5 VDC supply rail segmentation from the SLC chassis, enabling synchronized data transfer between CPU memory and external DeviceNet slave nodes. Diagnostic LEDs provide real-time visibility of network state, module status, and I/O transaction health independent of programming interface polling.

Frequently Asked Questions (FAQ)

Q: Does the 1747-SDN/B support simultaneous cyclic and COS messaging?
A: Yes. The scanner can execute cyclic polling while handling COS-triggered updates based on node configuration in the scanlist.

Q: What happens if DeviceNet node count exceeds 63 devices?
A: The scanner does not allocate addresses beyond 63 nodes; additional devices will not be scanned or mapped in M0/M1 structures.

Q: Can the module be hot-swapped in an energized SLC chassis?
A: No. Removal or insertion must be performed with chassis power removed to prevent backplane corruption and DeviceNet scanlist loss.

Field Installation Guidelines

• Install module into any SLC 500 chassis slot following processor slot rules.

• Ensure stable 5 VDC backplane supply before module insertion.

• Use approved DeviceNet trunk cabling and correct termination resistors at both ends of the network.

• Maintain proper shield grounding on DeviceNet cable to reduce CAN bus noise coupling.

• Configure scanlist using RSNetWorx prior to network commissioning.

• Verify LED sequence during startup to confirm network initialization and node discovery.