XIYUAN ST31D20 Integrated Vibration & Temperature Sensor - 0-20mm/s, 4-20mA RMS, IP65

The ST31D20 operates on a standard two-wire 4-20mA loop, requiring a DC power supply between 15 and 30 volts. The supply powers the sensor, and the measured vibration and temperature data is conveyed by modulating the loop current between 4mA and 20mA. Ensure your PLC or data acquisition system can provide this loop power on its analog input channel.

The single 4-20mA output carries both parameters. Typically, the lower portion of the range (e.g., 4-12mA) is mapped to the vibration velocity (0-20mm/s), while the upper portion (e.g., 12-20mA) represents the temperature (-50°C to +300°C). You must configure your receiving system (PLC/DCS) with the correct scaling based on the sensor's datasheet to separate and display the two measurements accurately.

For reliable high-frequency response, mount the sensor directly onto a clean, flat, and unpainted machine surface using a stud or strong adhesive mount. The mounting point should be as close as possible to the bearing or vibration source of interest. Ensure the surface is free of oil, debris, and rust to guarantee a solid mechanical connection, which is critical for measurement fidelity up to 1000Hz.

Yes, the ST31D20's IP65 rating makes it suitable for outdoor or damp industrial environments. It is protected against dust ingress and low-pressure water jets from any direction. However, it is not submersible. For prolonged exposure to heavy rain or direct high-pressure washdown, additional protective housing or a higher IP-rated model should be considered.

The sensor is factory calibrated for both vibration velocity and the integrated Pt100A temperature element. Field calibration is generally not required for the vibration channel. If extreme accuracy for temperature is needed, the Pt100A output can be verified against a known reference. Calibration of the entire 4-20mA loop should be performed using a precision current source and a calibrated vibration reference to ensure the scaling in your control system is correct.