Configured for network I/O data scanning and DeviceNet field device management in PLC-5 architectures, the Allen-Bradley 1771-SDN (1771-SDN DeviceNet Scanner Module) provides direct physical/electrical execution.

DeviceNet Interface Structure

The Allen-Bradley 1771-SDN module bridges the 1771 backplane bus with field-level DeviceNet networks. Equipped with 2 communication channels, it manages Master/Slave I/O exchanges, explicit messaging routines, and device status tables for up to 63 node addresses per port without increasing PLC-5 processor sweep times.

Mechanical & Electrical Technical Data

Deterministic Networking & Controller Firmware Integration

The unit transfers mapped I/O memory tables across Profinet / EtherNet/IP deterministic networks via gateway links, supporting high-capacity I/O density scaling. Operating parameters and device scan lists align through firmware flash compatibility routines, enabling deterministic polling cycles and quick network status verification within standard 1771 backplane rack structures.

Package Component List

• 1 x Allen-Bradley 1771-SDN DeviceNet Scanner Module

• 1 x DeviceNet Terminal Plug Assembly

• 1 x Installation and Wiring Instruction Sheet

Field Cabinet Installation Procedures

• De-energize the 1771 rack chassis power supply before inserting or removing the scanner card.

• Slide the module into the card guide slots until the top and bottom chassis latches snap into position.

• Wire the 5-conductor DeviceNet trunk line to the front terminal plug, maintaining correct wire color coding.

• Install 121 ohm terminating resistors across the CAN_H and CAN_L lines at both physical ends of the main trunk line.

• Earth the DeviceNet cable shield drain wire at one point only to prevent ground loop currents.

Engineering Support FAQ

• What is the primary operational function of the 1771-SDN module?

  The module scans DeviceNet network nodes, maps field device I/O into PLC-5 data tables, and handles explicit messaging.

• How many DeviceNet channels are built into the 1771-SDN scanner?

  The front interface includes 2 independent DeviceNet channels for concurrent field network communication loops.

• Can the 1771-SDN module be installed while the backplane is powered?

  No, the 1771 chassis requires complete power isolation before module insertion or removal to prevent hardware damage.

• What backplane current load does the scanner draw from the 1771 rack?

  The 1771-SDN draws up to 1.0 A at 5 VDC from the local 1771 rack backplane power supply rail.

• What termination resistance is required on the DeviceNet channels?

  A standard 121 ohm, 1/4 W metal film terminating resistor must be attached across CAN_H and CAN_L at trunk line endpoints.

• How are network node configurations maintained during system upgrades?

  Scan lists and node mappings integrate directly into the module memory using firmware flash compatibility features.

• What ambient temperature range is allowable for cabinet mounting?

  The card functions reliably in industrial enclosures operating within temperature limits of 0 to 60 deg C.

• How is shielding handled on the DeviceNet network connections?

  The drain wire of the shielded twisted-pair cable must be grounded at a single central point along the trunk line.