Yokogawa Electric Corporation S9221AQ-0 PLC Module

The Yokogawa ST5*A PLC Module Card AS-S9221AQ-0 / S9771AJ-0 (commonly cataloged as S9221AQ-0) is a plug-in control board designed for use in Yokogawa PLC and CENTUM DCS architectures to handle control processing and internal signal interfacing within distributed control systems. It is a rack-mounted, dual-layer PCB module that plugs into Yokogawa control cabinets to provide the processing backbone and signal routing necessary for coordinated plant operation. This legacy / surplus module supports system control, signal routing, and internal communication within industrial process control environments, and is commonly installed in industrial automation cabinets for system operation and signal handling. Typical applications include oil & gas, chemical plants, and manufacturing facilities where control logic and I/O interfacing are required in PLC or DCS setups. Key specifications include Manufacturer: Yokogawa; Model / Part Number: ST5*A / AS-S9221AQ-0 / S9771AJ-0; Product Type: PLC Module Card / Control Board; Form Factor: Plug-in module card; Construction: Dual-layer PCB; Installation: Rack-mounted; Status: Legacy / surplus industrial module; System Compatibility: Yokogawa PLC and CENTUM DCS systems. For maintenance and replacement, common replacements include Yokogawa EA9A Interface Card, EA1A Signal Interface Module, and AIP413 Control Module.