RDP Electronics S7TW Transducer

The S7TW is a two‑wire, loop‑powered oscillator/demodulator in‑line signal conditioner for LVDT transducers, delivering a 4‑20 mA output from a single input and designed to be mounted close to the transducer for early signal boost. It accepts 1 LVDT input, supplies 0.5 V AC excitation to the transducer, and is powered from 12‑36 V DC with an output current in the 4‑20 mA range. Coarse and fine gain controls plus a zero trim allow calibration across a wide range of RDP transducers, and a filter selects an optimum bandwidth/noise performance; the differential signal amplifier enables longer transducer cables. The two‑wire supply/output scheme provides compatibility with long cable runs and high noise immunity. Typical electrical bandwidth is 0–250 Hz (25 Hz when the filter is on). Enclosed in a die‑cast aluminum housing, the S7TW carries an IP65 rating and weighs about 1 kg, with enclosure dimensions around 125 × 113 × 80 mm. It is compatible with most standard RDP LVDTs (without integral electronics) and many third‑party units; some transducers require a TM202 modification to meet primary impedance, and the unit is not suitable for differential or half‑bridge transducers. This device is used to condition and convert transducer signals for PLCs, data loggers, and other 4‑20 mA instrumentation in industrial environments.