Fluke 971 User 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.
971
Temperature Humidity Meter
Users Manual

bdm003f.eps

1
Introduction
WCaution
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
WImportant information.
See manual BLow battery when shown in
the display.
PConforms to European
Union requirements ;Conforms to Australian
standards.
)Conforms to Canadian
standards OPower ON / OFF

971
Users Manual
2
Display
1
3
7
6
4
5
2
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No. Symbol Meaning
1 BLow battery.
2 Wet bulb or dew point temperature displayed.
3 M
MAX, MIN,
AVG
Min Max Record enabled.
Maximum, minimum, or average reading
displayed.
4 °F, °C Temperature measurement units.
5 % RH Relative humidity measurement unit.
6 L
88
Displayed reading is from memory.
Memory location number.
7 HHOLD enabled. Display freezes present
reading.

Temperature Humidity Meter
Operation
3
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 Oto 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 Wonce.
Press Wagain 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 Icauses the meter to freeze the displayed
readings. It also causes the meter to stop taking
measurements. His displayed when HOLD is enabled.
To continue taking measurements, press Iagain.

971
Users Manual
4
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 Nto start Min
Max Record. Mappears 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 Nrepeatedly 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 Na fourth time displays the
present measurement.
To exit Min Max Record mode and resume normal operation,
press and hold Nfor 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.

Temperature Humidity Meter
Operation
5
Pressing Ssaves the present readings to a memory
location. Land the memory location number appear in
the display to indicate the readings have been stored. Press
Wto 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 Rfor 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 Rfor 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.

971
Users Manual
6
Maintenance
Battery Replacement
Meter power is supplied by four 1.5 V (AAA size) batteries.
When Bappears 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.

Temperature Humidity Meter
Maintenance
7
APO
Enable/Disable
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Figure 1. Battery Compartment
Cleaning
WCaution
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.

971
Users Manual
8
Specifications
Temperature
Range:
Accuracy:
Resolution:
Update rate:
Sensor type:
-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
Relative Humidity
Range:
Accuracy:
Resolution:
Response time:
Sensor hysteresis:
Sensor type:
Temperature
Coefficient:
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)
Wet Bulb Temperature
Range: -20 to 60 °C (-4 to 140 °F)
Dew Point Temperature
Range: -50 to 60 °C (-58 to 140 °F)