Allen-Bradley 1747-SN Remote IO Scanner Module

The Allen-Bradley 1747-SN Remote I/O Scanner Module is the central interface in SLC 500 Remote I/O networks, connecting an SLC 5/02, 5/03, 5/04, or 5/05 processor to remotely located I/O via the AB Remote I/O (RIO) link. It enables discrete input and output data to be transferred between the controller and remote adapters such as 1746 chassis and other RIO‑compatible devices, effectively enabling distributed I/O scanning across the network. The module defines its data map with SCAN_IN and SCAN_OUT areas of 32 points each, and M0_SIZE and M1_SIZE of 32 words each, with G_FILE configured as 3. A 1/2 watt terminating resistor is included with the module and must be attached across line 1 and line 2 of the RIO link at each end of the network. In operation, the 1747-SN can draw up to 600 mA and relies on the Remote I/O link to exchange I/O status, messages, and diagnostics between the SLC processor and remote devices.