EXTECH 421502 User Guide

User Guide

Temperature and Humidity Datalogger

Model 42280

Introduction

Congratulations on your purchase of the Extech 42280 Thermometer and Relative Humidity
Datalogger. The 42280 is a wall-mount, tripod mount, or desktop indoor air quality monitor with an
internal memory capable of storing 16,000 readings (8000 temperature readings and 8000 relative
humidity readings) that can later be transferred to PC using the USB interface. Real-time meter­to-PC logging is also supported. This meter is shipped fully tested and calibrated and, with proper
use, will provide years of reliable service.

Material list

Supplied Materials

 Meter

 User Guide

 USB cable

 Program CD

 Four (4) batteries; 1.5V ‘AA’

 9V adaptor

Optional accessories

 Calibration bottles (33% and 75%) for Relative Humidity Calibration

Features

 Large LCD display shows temperature, humidity, and date/time clock simultaneously

 16,000 internal memory capacity (8000 temperature; 8000 RH%)

 Visual and Audible (with 117V AC adaptor only) Alarms

 Easily configure datalogger through the keypad or via PC interface

 USB PC interface with Windows

 Wall mount, tripod mount, or for desktop use

TM

software

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Description

Meter Description

1. Humidity Sensor (internal Temperature sensor)

2. Audible alarm (with AC adaptor power only)

3. Visual Alarm LED

4. Relative Humidity display

5. Date and Time display

6. Temperature display

7. RECORD status LED

8. USB port

9. AC Adaptor jack

10. Datalogger START-STOP button

11. MODE button

12. SET button

13. Up Arrow button

14. Down Arrow button

15. Tripod mount jack

Notes: The battery compartment is located on rear of instrument. Desktop stand footers are not

shown in diagram.

LCD Display Description

1. Temperature Display

2. Dew Point icon

3. Datalogger icon

4. Date and Time

5. Humidity Display

6. Low battery icon

1

2

3

4

5

15

2
3
6

4

10

DP

REC

Y-M-D
H:M:S

131211 14

%

6

7

1

5

8

9

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Operation

Important Note before starting

This meter relies on firm button presses to operate correctly. Be sure to press firmly and hold the
button for as long as directed in the instructions.

Meter Power

1. The meter is powered by four (4) ‘AA’ 1.5V batteries or the 117V AC adaptor.

2. When the batteries are installed or the adaptor is connected to an AC power source,
momentarily press the START-STOP button to turn the meter ON.

3. Press the START-STOP button again to turn the meter OFF.

Viewing the displayed readings

1. Normally, the top line indicates temperature in degrees C or F. Use the MODE button to switch
between degrees C and degrees F.

2. Press and hold the MODE for at least 2 seconds. This will change the top display to Dew Point
temperature. The ‘DP’ icon will appear on the LCD when in Dew Point mode. Press and hold the
MODE button for at least 2 seconds to return the top display to the normal temperature display
mode.

3. The middle line displays Relative Humidity in %.

4. The bottom line automatically alternates between Time and Date displays.

5. If the ALM status LED illuminates and the display flashes, one of the Alarm limits has been
reached. Program the High and Low Temperature/Humidity limits in Programming parameter P5
(detailed later in this user guide).

Datalogger Basics

The Model 42280 has a built-in Datalogger that can store up to 8000 temperature and 8000
humidity readings. Readings can be stored in the meter and transferred at a later time to a PC. The
meter can also display real-time readings on a connected PC; in other words, the PC can display
readings at the instant the readings are taken.

The meter must be configured
Clock and Datalogger Sample Rate must be programmed before datalogging can begin. It is
strongly recommended
Instructions for manually configuring the meter are provided below; however configuring the meter
via software is very convenient.

Basic instructions for connecting the meter to a PC and getting started with the supplied software
are provided later in this guide. Detailed instructions regarding the supplied software are provided in
a separate manual included on the supplied CD-ROM and the HELP utility in the software program.

before datalogging can be attempted. Parameters such as Real Time

that the user take advantage of the supplied software to configure the meter.

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Manual Programming

The Model 42280 has several programming modes (P1, P2, P3, P4, P5, and P6). These
parameters must be programmed before the Datalogger or the Alarm can be used.

List of Programming Modes

P1 - Number of samples to record (1, 2, 4, 8, 12, or 16 x 1000; 1=1000, 2=2000, etc.)

P2 - Datalogging Start Methods (Immediate, Keypad, Scheduled, and Repeat modes)

P3 – Start Time (set the time and date when Datalogging will automatically begin); Note that P3

will not appear in the menu if ‘SCh’ is not

P4 - Sample Rate (set the datalogging interval from 1 second up to 12 hours)

P5 - Alarm Mode (set High and Low Temperature/Humidity limits)

P6 - Real Time Clock (set the meter’s internal date and time clock)

Programming Mode P1; Number of readings (sample points) to record

1. Press the SET button to access the setup mode

2. Use the arrow buttons to select parameter P1 (see sample display below)

3. Press the SET button again

4. Use the up/down arrow buttons to select the

desired number of samples (in thousands) to record
for a datalogging session (1, 2, 4, 8, 12, or 16;
where 1=1000, 2=2000, 4=4000, and so on)

5. Press the SET button to save setting

6. Use the arrow buttons to select another programming mode or press MODE to exit the

programming mode.

selected in P2.

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