Extech 407445 Instruction Manual

INSTRUCTION MANUAL

Model 407445

Heavy Duty Hygro-Thermometer

• Displays Temperature & Relative Humidity

simultaneously

• High precision, capacitance RH probe

• Record / Recall MAX/MIN/AVG Readings

• PC Interface and Software

1. INTRODUCTION

Congratulations on your purchase of Extech’s Heavy Duty Hygro-Thermometer. This
professional meter, with proper care, will provide years of safe reliable service.

2. SPECIFICATIONS

2.1 General Specifications

Circuit Custom LSI microprocessor circuit
Display Dual function, 0.5" super large LCD display with

Measurement Relative Humidity (RH) and Temperature (°C & °F)
Data Hold function Freezes Display
Sensor Structure Humidity - thin film, capacitance sensor

Memory Recall Records/Recalls Max, Min and Average readings
Power off Automatic power down to preserve battery life
Data Output RS 232 PC serial interface
Sampling Time Approximately 0.8 seconds
Operating
Temperature
Operating Humidity < 90% RH
Power Supply 006P DC 9V battery (Heavy duty Alkaline type)
Power Current Approx. 8.5 mA DC
Weight 0.76 lbs. (345 g) including batteries & probe
Size Instrument: 7.1 x 2.8 x1.3" (180 x 72 x 32mm)

contrast adjustment

Temperature - thermistor

Instrument: 32 to 122F (0 °C to 50 °C)
Probe: 32 °F to 140 °F (0 °C to 60 °C)

Sensor Head: Round, 26mm diameter x 160mm

1 407445es Ver. 1.04 9/99

2.2 Range Specifications

RH 10% to 95% RH 0.1% RH >70% RH: +(3% rdg + 1% RH);

Temperature

3. FRONT PANEL DESCRIPTION

1. Humidity Display

2. Temperature Display

3. ON/OFF key

4. RECORD key

5. RECALL key

6. RS-232 output jack

7. Sensor input jack

8. Sensor head

9. LCD contrast adjustment

10. Temperature units select

11. Data Hold key

12. Sensor handle

4. OPERATION

4.1 Install the "Sensor Plug" into the "Sensor Input Socket .

4.2 Press "Power Off/On" to turn the instrument power "ON".

4.3 Select the temperature units by pressing "°C/ °F ". The display will indicate "°C" or
"°F" as selected.

4.4 The meter will now display up-to-the-minute humidity and temperature.

4.5 As humidity values of the environment change, it takes a few minutes to obtain a
stable RH reading.

NOTE: For accurate Relative Humidity measurements the meter should be allowed to
stabilize for several minutes in order to adapt to the ambient temperature of the area
where the test is taking place. Also, the probe should be held from the cable end when
making measurements.

4.6 Data Hold:

While taking measurements, pressing "Data Hold" will freeze the displayed value and the
LCD will display the "D.H" indicator. Press "Hold" again to release the data hold function.

4.7 Data Record (Max., Min., and Average RH reading):

When selected, the DATA RECORD function records and stores the max, min and
average readings. To start the DATA RECORD function:

a) Press "RECORD" once. The "REC" indicator will appear on the display.
b) Press "RECALL" once to enter the "Max" mode. The "Max" indicator along with the
maximum reading recorded since the “RECORD” key was first pressed will appear on
the LCD display.
c) Press "RECALL" once, the "Min" indicator along with the minimum reading recorded
since the “RECORD” key was first pressed will appear on the LCD display.

Range Resolution Accuracy

<70% RH: +3% RH

0οC to 50 οC

32 οF to 122 οF

0.1 οC

0.1 οF

2 407445es Ver. 1.04 9/99

+0.8οC
+1.5 οF