3A99166G0 is a single-width Eurocard dedicated LVDT excitation and pre-signal processing board used in thermal and nuclear power plant DEH control cabinets. It works in conjunction with 3A99164 main control card and all variants of 3A99165 servo drive boards to complete closed-loop valve position control. The card supplies stable AC excitation power to field-mounted LVDT displacement transducers fitted on turbine stop valves, governing valves and bypass valves. It picks up low-level millivolt AC feedback signals from LVDTs, then performs rectification, filtering and amplification to convert raw alternating signals into standardized ±10VDC analog position signals before forwarding processed signals to downstream servo amplifier cards. The module is mechanically interchangeable with follow-up revised versions and fits standard Ovation rack slots for direct plug-in installation without field wiring modification.

Operating power is sourced from rack backplane with +5VDC and ±12VDC supplied by 3A99132 series PCPS power modules. The board outputs fixed-frequency sine-wave excitation, typically 3kHz at 7VAC for multi-channel LVDT sensor power supply. Multiple independent measuring channels are integrated on one PCB to serve several separate valve feedback loops simultaneously. All signal input circuits are equipped with TVS surge suppression devices, channel-specific fuses and multi-stage RC filter networks. Built-in overcurrent and short-circuit latch protection prevents component damage caused by field cable short or transducer fault. Processed DC position output is calibrated to standard ±10VDC full scale matching the input specification of 3A99165 servo boards.

Continuous operating temperature inside sealed control cabinet ranges from -15℃ to +72℃, while storage temperature covers -40℃ to +90℃. The PCB is fully coated with moisture-proof, mould-proof and anti-salt-spray conformal coating to adapt severe industrial site conditions. The whole design complies with IEC61000 industrial EMC standards to resist electromagnetic noise from cabinet contactors and variable frequency drives. It adopts standard Ovation single-slot dimension consistent with other DEH series control cards for unified rack layout.

Front panel is equipped with LED indicators showing power status and channel fault alarms, and reserved test terminals allow on-site multimeter verification of excitation voltage and converted DC position signal during commissioning or overhaul. The card supports cold plug replacement under rack standby condition, and redundant configuration is commonly adopted on critical turbine control loops to improve system operational reliability.

Original OEM production has been discontinued; available stock consists of tested refurbished modules and inspected surplus original spare parts with standard 12-month warranty.

This single-width Eurocard functions as dedicated LVDT excitation source and signal preprocessing module. It cooperates with 3A99164 main controller and full-range 3A99165 servo drive boards to realize closed-loop valve positioning for turbine stop valves, governing valves and bypass valves. The card provides regulated AC excitation to field LVDT displacement sensors, collects weak millivolt alternating feedback signals, then rectifies, filters and amplifies raw signals into standardized ±10VDC analog outputs for downstream servo amplifier usage. It fits standard Ovation rack slots and allows direct drop-in replacement without field wiring changes.

Power is obtained from rack backplane +5VDC and ±12VDC, fed by 3A99132 PCPS series rack power supply. It generates 3kHz, 7VAC sine-wave excitation for multiple independent LVDT channels. Each input channel integrates TVS surge protection, dedicated fuse and multistage RC filter circuit, with embedded overcurrent and short-circuit lockout protection against field wiring faults or transducer damage. Final conditioned position signal is standardized to ±10VDC to match the input requirement of 3A99165 servo boards.

Operating ambient temperature inside enclosed cabinet ranges from -15℃ to +72℃; storage temperature spans -40℃ to +90℃. The entire PCB is covered with conformal coating against moisture, mould and salt fog. Product design meets IEC61000 EMC standards to suppress interference from contactors and variable frequency equipment in control rooms. Mechanical outline follows standard Ovation single-slot dimension consistent with other DEH series plug-in modules.

Front panel LED lamps display power status and channel fault alerts; reserved test points enable field measurement of excitation voltage and processed DC signal during commissioning or maintenance. The card supports cold-swap replacement when the rack is on standby, and redundant installation is widely applied for critical turbine control loops to enhance operational safety.

Original OEM production is discontinued; available supplies include fully tested refurbished units and surplus original spares with 12-month standard warranty.No excitation output usually results from blown onboard fuse or abnormal backplane power supply. Random signal fluctuation is commonly caused by loose field terminals or degraded filter components. Continuous DC zero drift mostly originates from aging preamplifier circuits or oxidized PCB gold finger contacts.