Fluke 971-NIST User manual

971

Temperature Humidity Meter

®

Users Manual

PN 2441047
September 2005 Rev.1, 5/06

© 2005-2006 Fluke Corporation, All rights reserved. Printed in Taiwan
All product names

are trademarks of their respective companies.

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Introduction

W Caution

To extend sensor life, keep the sensor’s
protective shutter closed whenever the meter is
not in use.

The Fluke Model 971 (hereafter referred to as “the Meter” is
a battery powered meter that measures relative humidity and
temperature. Through a few easy to use controls, the Meter
displays three different temperature points of the air
surrounding the meter’s sensor: ambient, wet bulb, and dew
point.

Electrical and Safety Symbols

Important information.

W

See manual

Conforms to European

P

Union requirements

Conforms to Canadian

)

standards

1

Low battery when shown in

B

the display.

Conforms to Australian

;

standards.

O Power ON / OFF

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971

Users Manual

Display

1

2

3

No. Symb ol Meaning

1

2

3

4

5

6

7

B Low battery.

Wet bulb or dew point temperature displayed.

M

MAX, MIN,

AVG

Min Max Record enabled.

Maximum, minimum, or average reading
displayed.

°F, °C Temperature measurement units.

% RH

L

88

H

Relative humidity measurement unit.

Displayed reading is from memory.
Memory location number.
HOLD enabled. Display freezes present
reading.

7

6

5

4

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Temperature Humidity Meter

Operatio n

Operation

Note

When moving from one temperature/humidity
extreme to another, allow time for the Meter to
stabilize.

After opening the sensor’s protective shutter, press O to turn
on the Meter and start taking measurements.

Temperature readings are displayed in either the
Celcius (°C) or Fahrenheit (°F) scale. To switch between °C
and °F, remove the battery compartment door and position
the temperature scale switch to the desired scale. See
Figure 1.

Dew Point and Wet Bulb Temperature

The Meter displays ambient temperature when first turned
on. To display dew point (DP) temperature, press W once.
Press W again to switch to wet bulb (WB) temperature.
Pressing Wa third time returns the Meter to ambient
temperature. The display indicates when dew point and wet
bulb temperatures are selected.

HOLD

Pressing I causes the meter to freeze the displayed
readings. It also causes the meter to stop taking
measurements. H is displayed when HOLD is enabled.
To continue taking measurements, press I again.

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971

Users Manual

Min Max Record

When enabled, Min Max Record stores a new measurement
when it is either higher or lower than a previously stored
maximum or minimum measurement. Press N to start Min
Max Record. M appears in the display to indicate Min
Max Record mode is enabled.

Note

The temperature scale switch (°C/°F), Save, Recall,
and Hold buttons, as well as the Automatic Power
Off (APO) switch are all disabled when Min Max
Record is enabled.

To view the stored Minimum, Maximum and Average
readings, press N repeatedly to cycle through all three
stored sets of measurements. You must select wet bulb, dew
point, or ambient before reading their respective Min Max
Avg values. The display indicates which stored set of
readings is displayed. Pressing N a fourth time displays the
present measurement.

To exit Min Max Record mode and resume normal operation,
press and hold N for two seconds.

Saving and Recalling Measurements

The Meter stores up to 99 readings for later recall. Each
memory location stores relative humidity as well as ambient,
dew point and wet bulb temperatures.

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Temperature Humidity Meter

Operatio n

Pressing S saves the present readings to a memory
location. L and the memory location number appear in
the display to indicate the readings have been stored. Press
W to return the display to the present reading. After all 99
memory locations are filled, each subsequent save
overwrites a memory location starting with the first.

To recall the readings from memory, press R. If the
memory location you are looking for is not already displayed,
press ▲ or ▼ until the desired memory location is displayed.
To return the Meter to normal operation, press R for two
seconds.

By default, relative humidity and ambient temperature are
displayed when a memory location is recalled. Pressing W
cycles through the Wet Bulb, Dew Point, and Ambient
temperatures stored in the memory location displayed.

To erase all 99 memory locations, simultaneously press S
and R for five seconds.

Automatic Power Off

To save battery life, the Automatic Power Off (APO) feature
can be used to turn the meter off after 20 minutes of no
activity. To enable or disable the APO feature, remove the
battery cover and position the APO switch to the desired
position. See Figure 1.

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Maintenance

Battery Replacement

Meter power is supplied by four 1.5 V (AAA size) batteries.
When B appears in the display, replace the batteries as
soon as possible. To replace the batteries:

1. Back out the screw at the top of the battery door and lift
the door away from the Meter.

2. Remove the four AAA batteries from the compartment.

3. Replace with four new AAA batteries, observing proper
polarity as depicted on the bottom of the battery
compartment.

4. Replace the battery door and tighten the screw to lock it
in place.

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Temperature Humidity Meter

Mainte nance

APO

Enable/Disable

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Figure 1. Battery Compartment

Cleaning

W Caution

To avoid damage to the case, do NOT use
abrasives or solvents for cleaning the meter.

Periodically wipe the case with Fluke Meter Cleaner or a
damp cloth and detergent.

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Specifications

Temperature
Ra nge:

A ccuracy:

Resolution:

Update rate:

Sensor type:

Relative Humidity
Ra nge:

A ccuracy:

R esolution:

R esponse time:

Se nsor hysteresis:

Se nsor type:

T emperature
Co efficient:

Wet Bulb Temperature
Ra nge:

Dew Point Temperature
Ra nge:

-20 to 60 °C (-4 to 140 °F)

±0.5 °C on 0 to 45 °C
±1.0 °C on -20 to 0 °C, 45 to 60 °C

±1.0 °F on 32 to 113 °F
±2.0 °F on -4 to 32 °F, 113 to 140 °F

0.1 °C /°F

500 ms

NTC

5 to 95 % RH

±2.5 % RH (10 to 90 % RH) @23 °C
(73.4 °F)
±5.0 % RH (<10, >90 % RH) @23 °C
(73.4 °F)

0.1 % RH

60 seconds max.

±1 % RH with excursion of 90 % to 10 %
to 90 %

Electronic–capacitance polymer film

0.1 x (specified accuracy)/°C (< 23 °C or
> 23 °C)

-20 to 60 °C (-4 to 140 °F)

-50 to 60 °C (-58 to 140 °F)

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Temperature Humidity Meter

Specific ations

Memory: 99 data points

Power: 4 each AAA batteries, 24A, LR03

Battery Life: 200 hours

Environment
Storage:

Operating:

Weight/Dimensions: 190 g with batteries

Safety Approvals/
Certifications:

Specifications subject to change without notice

-20 to 60 °C at <80 % R.H. (Batteries
removed)
Temperature: -20 to 60 °C
Humidity: 0 to 55 °C

194 mm x 60 mm x 34 mm

; Meet s Australian requirements

) Meets CSA requirements

P Me ets European requirements

Meets EN61326-1, Schedule B
Electromagnetic Emissions and
Susceptibility

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971

Users Manual

LIMITED WARRANTY AND LIMITATION OF LIABILITY

This Fluke product will be free from defects in material and
workmanship for one year from the date of purchase. This
warranty does not cover fuses, disposable batteries, or
damage from accident, neglect, misuse, alteration,
contamination, or abnormal conditions of operation or
handling. Resellers are not authorized to extend any other
warranty on Fluke’s behalf. To obtain service during the
warranty period, contact your nearest Fluke authorized
service center to obtain return authorization information, then
send the product to that Service Center with a description of
the problem.

THIS WARRANTY IS YOUR ONLY REMEDY. NO OTHER
WARRANTIES, SUCH AS FITNESS FOR A PARTICULAR
PURPOSE, ARE EXPRESSED OR IMPLIED. FLUKE IS
NOT LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL
OR CONSEQUENTIAL DAMAGES OR LOSSES, ARISING
FROM ANY CAUSE OR THEORY. Since some states or
countries do not allow the exclusion or limitation of an implied
warranty or of incidental or consequential damages, this
limitation of liability may not apply to you.

11/99

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