| 摘要 |
<p>A variable differential transformer system (10), both linear and rotary (L/RVDT) includes a primary coil (12) drive by a primary drive (20) having a triangle wave generator whose frequency is set by an external frequency control (Rosc and Cosc) which provides compensation for gain temperature error. Secondary coils (14, 16) have a common connection for balanced loading with an input stage arrangement (R7, R8, R9, R10) providing low common mode range and a way to differentiate between normal operation and coil faults detected by a fault detection network (28). Synchronous demodulation (22) extracts both magnitude and direction from the secondary coil signals. Electronic calibration (24) compensates for sensor offset and adjust circuit gain by adding a percentage of the synchronous demodulation reference waveform to the secondary differential voltage. A filter network (26) averages the synchronous demodulated signal in order to extract the DC component of the waveform which is amplified (30) to provide drive current to interface with external loads. A variable rotary core assembly (18) and a variable linear core assembly (18') are shown which allow axial adjustment of the core relative to the coils to provide balancing of the out-of-phase component of the secondary voltage waveform to provide offset temperature error compensation without significantly affecting the in-phase component of the secondary waveform. <IMAGE></p> |
