The Allen-Bradley 1771-ASB, also cataloged as the 1771-ASB Remote I/O Adapter, operates as a dedicated hardware component for high-speed backplane data translation and serial scanning within PLC-5 RIO Network platforms.
The module manages backplane bus communication velocity and deterministic serial polling across extended physical spans. Configured directly on the remote node backplane, the adapter maps up to 32 I/O points across designated 1/2-slot, 1-slot, or 2-slot addressing configurations. Physical connection over blue hose twinaxial cable enables deterministic data transfer rates up to 57.6K Baud at distances reaching 10,000 cable feet, maintaining tight scan synchronization between the host processor and remote chassis.
Frequently Asked Questions
Q: What are the backplane power supply requirements for the 1771-ASB?
A: The adapter draws up to 1.2 A at 5 VDC directly from the 1771 chassis backplane power supply. Ensure the local chassis power supply maintains sufficient current overhead during operation.
Q: Can the 1771-ASB be inserted or removed while the backplane is powered?
A: No. Power to the 1771 chassis backplane must be completely isolated prior to insertion or removal to prevent electrical transients and backplane communication disruption.
Field Installation Guidelines
Isolate system power from the target 1771 chassis prior to inserting or removing the adapter module.
Set internal configuration jumpers for baud rate, node address, and rack addressing modes according to system design specifications.
Align the module card edge with the guide rails of the leftmost chassis slot (Slot 0) and slide it inward until fully seated into the backplane connector.
Secure the module using the top and bottom chassis latching mechanisms to maintain frame ground contact.
Terminate the twinaxial network cable to the screw terminals on the field wiring arm, maintaining proper shield wire grounding and installing required terminating resistors at both physical ends of the RIO trunk.
