Key facts
- Brand
- EXTECH
- Model
- HD500
- Documents
- 3
- Languages
- ZH · EN
- Last added
- 2026-10-06
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Extech HD500 Heavy Duty Hygrometer User Guide
This guide introduces the Extech HD500 heavy‑duty hygrometer, a handheld instrument that measures air temperature, relative humidity, dew point, wet‑bulb temperature and surface temperature with an integrated infrared sensor and K‑type thermocouple input. It describes the instrument’s layout, buttons, display icons and safety warnings for laser use.
Operational instructions cover basic measurements, switching between temperature, wet‑bulb and dew‑point modes, infrared surface temperature measurement, data hold, min/max recording, auto‑shutdown settings, battery replacement, backlight control and USB PC communication. The manual also provides infrared measurement considerations, emissivity tables, general specifications and detailed temperature/humidity range specifications. This manual is written in Chinese.
EXTECH HD500 specifications
| Display | Dual‑function LCD, 9999 pixels |
|---|---|
| Sample rate | 1 reading per second |
| Temperature sensor | Thermistor |
| Humidity sensor | Capacitive relative humidity |
| Infrared distance‑to‑spot ratio | 30:1 |
| Infrared spectral response | 6 µm to 14 µm |
| Infrared emissivity setting | 0.95 |
| Operating temperature range | 32 °F to 122 °F (0 °C to 50 °C) |
| Relative humidity range | up to 80 % |
| Dimensions | 10.1 × 3.0 × 2 in (257 × 76 × 53 mm) |
| Weight | 12.5 oz (355 g) |
All EXTECH HD500 documents by type
Day-to-day operation, settings and troubleshooting. Start here if the product is already set up.
Questions answered in these manuals
How do I switch between temperature, wet‑bulb and dew‑point displays?
Press the WB/DP button to toggle among air temperature, wet‑bulb temperature and dew‑point readings.
How do I disable the auto power off feature?
Hold the IRT button and then press the Power button to turn on; release the IRT button when 'disAPO' appears.
From: Extech HD500 Heavy Duty Psychrometer + IR Thermometer User Guide
What is the IR Distance to Spot ratio?
The meter's field of view ratio is 30:1.
From: Extech HD500 Heavy Duty Psychrometer + IR Thermometer User Guide
What is the accuracy of the humidity measurement?
The instrument provides a highest 2% RH accuracy.
From: Extech Instruments HD500 Psychrometer with IR Temperature Product Datasheet
Does this model include software?
Yes, it includes Windows compatible software with a USB cable and port.
From: Extech Instruments HD500 Psychrometer with IR Temperature Product Datasheet