EXTESH HT30 User Guide

User's Manual

Heat Stress WBGT Meter

Model HT30

Introduction

Congratulations on your purchase of Heat Stress WBGT (Wet Bulb Globe Temperature) Meter. This
meter measures and displays Heat Stress Index (WBGT), which is how hot it feels when humidity is
combined with temperature, air movement, and direct or radiant sunlight. Black Globe Temperature
(TG) monitors the effects of direct solar radiation on an exposed surface. It also measures air
temperature (TA) and Relative Humidity (RH). Additional features include: selectable units of °F/°C,
Auto power off with override, and a built-in RS-232 interface with optional 407752 Windows®
software. This meter is shipped fully tested and calibrated and, with proper use, will provide years of
reliable service.

Meter Description

1. Black Globe temperature sensor

2. RH and Temperature sensors with protective cover

3. LCD display

/SET

4.

5. NEXT

6. MODE/

7. RS-232 interface

8. Battery compartment (on rear)

DISPLAY

Symbol Function

WBGT Wet Bulb Globe Temperature

TG Black Globe Temperature

TA Air Temperature

RH% Relative Humidity

OUT Indoor (no sun)

IN Outdoor (in full sun)

C/F Celsius/Fahrenheit

Low Battery indicator

S

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Meter Operation

1. Press the /SET button to power the instrument on/off.

2. Slide down the protective sensor cover before taking measurements.

3. Press the MODE/
Heat Index (WBGT), Air Temperature (TA), Black Globe Temperature (TG), or Relative
Humidity (RH). An icon will appear in the display indicating the current selection.

4. To select the preferred temperature unit (°F or °C), simultaneously press and release the

Sand NEXT buttons. The F or C icon will appear in the display.

MODE/

5. The meter measures WGBT index with (IN) or without (OUT) direct sun exposure. Hold down
the MODE/

appear in the display.

Alarm Setting

The HT30 has a user settable heat stress index alarm. The HT30 will emit an audible beep when
the heat stress index (WBGT) reaches the level previously set by the user. The alarm will continue
beep until the measured heat stress index temperature falls below the alarm level set by the user, or
the meter is turned off. The setting range is from 68.0 to 99.0°F (20.0 to 37.2°C).

1. To enter the alarm setup mode, hold down the

turning the meter on.

2. The current alarm setting will be displayed with the most significant digit blinking.

3. Use the MODE/

4. To set the next digit, momentarily press the NEXT button.

5. After all of the digits are set, press and hold the NEXT button for 2 seconds to return to the
measuring mode.

NOTE: The OUT icon will appear in the display If the new setting is out of the setting range of the

alarm.

Sbutton to select the desired display mode: Wet Bulb Globe Temperature

S for more than 1 second to alternate between settings. The IN or OUT icon will

/SET button for more than 2 seconds when

Sbutton to increment the digit.

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