The VP-4 sensor probe is an accurate tool to measure air temperature, relative humidity (RH), vapor pressure, and barometric pressure in soil and in air. A microprocessor within the sensor calculates vapor pressure from the RH and temperature measurements. The sensor uses a sensor chip to measure both air temperature and RH and a secondary chip to measure barometric pressure.
Specifications
General specifications
Operating temperature: −40 to 80 ºC
Measurement time: 300 ms
Dimensions: 1.96 cm (dia) x 5.4 cm (h)
Cable length: 5 m
Vapor pressure
Range: 0 to 47 kPa
Resolution: 0.001 kPa
Temperature
Range: −40 to 80 ºC
Resolution: 0.1 ºC
Equilibration time: < 400 s
Long term drift: < 0.04 ºC/year typical
Barometric pressure
Range: 49 to 109 kPa
Resolution: 0.01 kPa
Accuracy: 0.4 kPa
Relative humidity
Range: 0 to 100% RH
Resolution: 0.1% RH
Equilibration time: <40 s
Hysteresis: <1% RH typical
Long term drift: <0.5% RH/year typical