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Page 4                                                                                                                          Model 407445 Version 2.2 February 2004

 

Meter Operation 

Getting Started 

1. 

Plug the sensor into the sensor jack at the top of the meter. 

2. 

Press the Power OFF/ON key to turn the instrument on or off. 

3. 

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

4. 

The meter will now display the per cent relative humidity and the temperature. 

 
NOTE: 

For accurate relative humidity measurements the meter should be allowed 

several minutes to adjust to ambient temperature changes. 
 

Data Hold 

Press the Data Hold key to freeze the displayed temperature and humidity readings. The 
HOLD icon will appear on the display in the Data Hold mode. Press the Data Hold key 
again to exit the Data Hold mode. 
 

MAX, MIN, and AVG Record / Recall 

1.  Press the RECORD key to begin. The REC indicator will appear on the display and the 

meter will begin tracking the highest (MAX), lowest (MIN), and average (AVG) 
readings. 

2.  Press the RECALL key to display the highest (MAX) reading. The MAX indicator along 

with the maximum reading recorded since RECORD was first pressed will appear.  

3.  Press the RECALL key again to view the lowest (MIN) reading.  

4.  Press the RECALL key again to view the average reading (AVG). 

5.  To exit, press the RECORD key. 

Measurement Considerations 

1.  The meter includes an Auto Power OFF feature that turns the instrument off after 

approximately 10 minutes of inactivity. To disable this feature, press the RECORD key 
to enable the MIN/MAX/AVG function. 

2.  It may be necessary to adjust the display contrast due to a change in viewing angle or 

voltage drift. Use the LCD contrast adjustment located on the right side of the meter. 

Summary of Contents for 407445

Page 1: ...ro Thermometer Introduction Congratulations on your purchase of Extech s Heavy Duty Hygro Thermometer The Model 407445 displays Temperature Relative Humidity simultaneously and includes a built in PC interface This professional meter with proper care will provide years of safe reliable service ...

Page 2: ...off after approx 10 minutes of inactivity Data Output RS 232 PC serial interface Sampling Time Approximately 0 8 seconds Operating Temperature Instrument 32 to 122 F 0 to 50 C Probe 32 to 140 F 0 to 60 C Operating Humidity 90 RH Power Supply 9V battery Power Consumption Approx 8 5 mA DC Weight 0 76 lbs 345 g including batteries probe Size Instrument 7 1 x 2 8 x 1 3 180 x 72 x 32mm Sensor head 1 di...

Page 3: ...Version 2 2 February 2004 Meter Description 1 Sensor input 2 RS 232 serial output jack 3 LCD Display 4 Keypad 5 Sensor 6 LCD contrast adjustment 7 Protective rubber jacket 8 Battery compartment and calibration pots on rear ...

Page 4: ...a Hold mode MAX MIN and AVG Record Recall 1 Press the RECORD key to begin The REC indicator will appear on the display and the meter will begin tracking the highest MAX lowest MIN and average AVG readings 2 Press the RECALL key to display the highest MAX reading The MAX indicator along with the maximum reading recorded since RECORD was first pressed will appear 3 Press the RECALL key again to view...

Page 5: ...l accompanying the 407001 software package Battery Replacement 1 The low battery indicator LBT appears on the left corner of the display when the battery requires replacement Reliable readings can be obtained for several hours after the first appearance of the low battery indicator 2 To replace the battery a Remove the rubber jacket that encases the meter b Open the rear battery compartment using ...

Page 6: ...n reference solution Wait for a stable reading up to 30 minutes Adjust VR3 until the display reads 33 0 5 Place the sensor head into the 75 calibration reference solution Wait for a stable reading up to 30 minutes Adjust VR4 until the display reads 75 0 Temperature Calibration Note that the temperature calibration adjustments are rarely required However if a temperature calibration is in order the...

Page 7: ...calibration services for the products we sell Extech also provides NIST certification for most products Call the Customer Service Department for information on calibration services available for this product Extech recommends that annual calibrations be performed to verify meter performance and accuracy ...

Page 8: ...0 7440 ext 210 for authorization or visit our website www extech com for contact information A Return Authorization RA number must be issued before any product is returned to Extech The sender is responsible for shipping charges freight insurance and proper packaging to prevent damage in transit This warranty does not apply to defects resulting from action of the user such as misuse improper wirin...

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