Vaisala HMT140 Temperature and Humidity Data Logger

The Vaisala HMT140 is a reusable Wi-Fi temperature logger that records temperature and relative humidity from -40 to +80°C. Vaisala specifies the HMT140 at ±0.2°C (+15 to +25°C), ±0.25°C (0 to +15°C, +25 to +40°C), ±0.4°C (-40 to 0°C, +40 to +80°C) accuracy. On the HMT140, humidity is measured from 0 to 100 %RH at ±1.5 %RH (0 to 90 %RH), ±2.5 %RH (90 to 100 %RH) at 0 to +40°C; ±3.0 %RH (0 to 90 %RH), ±4.0 %RH (90 to 100 %RH) at -40 to 0°C and +40 to +80°C. Down to -40°C, the HMT140 covers 2–8°C fridges as well as -20°C freezers. The probe is hMP110 HUMICAP 180R humidity and temperature probe on a 3 m, 5 m or 10 m cable.

Memory holds 3,060 readings with an interval settable from 2 min to 60 min, about 32 days of logging at 15-minute steps. The HMT140 sends readings over Wi-Fi to Vaisala viewLinc, so alerts arrive while the logger is in place.

Physically, the HMT140 has Optional LCD (128 × 64 B&W, no backlight) display and IP65 protection. Listed approvals for the HMT140: FCC, RCM, RoHS, EN 61326-1, EN 301 489-1, EN 300 328 and EN 61010-1. For calibration, the HMT140 comes with: traceable to SI units through national metrology institutes or ISO/IEC 17025 accredited laboratories. In practice the Vaisala HMT140 fits cold rooms, fridges and warehouses with 24/7 alerts, 2–8°C or frozen.