This COT electro-optic repeater card is developed for long-distance isolated bus transmission between DPU main controllers and remote I/O cabinets in thermal & nuclear power plant DCS. It converts parallel Q-crate backplane electrical bus data into optical signal for fiber transmission, and recovers incoming optical data back to standard backplane signal. Two units are paired and mounted inside 5D32207G01 clamshell COT chassis to construct full-duplex fiber communication links, cooperating with MDPS power modules (3A99116G series), AI/AO analog boards to build distributed remote I/O networking for steam turbine governing, valve control and boiler auxiliary closed-loop control systems.G03 is the final production upgrade version compared with G02; it optimizes internal optical drive circuit, anti-interference filter and temperature compensation design to minimize intermittent communication dropout under high-temperature and heavy EMI cabinet environment.

The module draws +5V and ±12VDC operating power directly from Q rack backplane powered by MDPS power supply card. It is configured with dual ST fiber connectors, factory default SUB-F optical configuration matching 12-core industrial fiber cable (2COT12 specification), compatible with single-mode fiber layout; maximum rated transmission distance reaches 2000m under standard ambient condition. On-board matched transceiver chips follow native WDPF Q-bus communication rate with built-in frame synchronization and error correction circuit. Front panel LED indicators display power status, optical transmit channel and optical receive channel fault separately for on-site quick diagnosis.

Rated continuous operating temperature: 0°C ~ +55°C for indoor cabinet fixed installation; storage temperature range: -40°C ~ +85°C. Permitted working humidity: 5%~95% non-condensing RH without corrosive gas and conductive dust. Whole board complies with IEC61000 EMC industrial anti-interference standard for severe electromagnetic field inside power station control room.

Standard Q-Line plug-in structure fits all standard 9-slot Q-type crate slots, no wiring modification required during field replacement of G01/G02 with G03. Complete self-test will start automatically after rack power-on before fiber connection; connect ST fiber pigtails only after passing onboard self-check to confirm normal link status before formal system commissioning.

Original OEM production is discontinued; available stock includes factory tested refurbished and surplus original spare modules. Standard repair cycle is 2–4 weeks with expedited emergency repair available for critical plant breakdown. Global courier delivery via DHL/UPS/Fedex is supported, and tested replacement units come with standard 12-month after-sales warranty.

Total link failure of paired cards mainly arises from abnormal +5V/±12V output of MDPS power board or rack fuse damage. Random unstable communication mostly results from contaminated ST fiber end face, mismatched fiber core specification or poor cabinet protective earthing. Single Tx/Rx channel breakdown needs separate inspection of internal optical transceiver component and PCB solder circuit.