Triplett RHT37 User Manual

User Manual

RHT37

Dual Input Hygro-Thermometer
Psychrometer

Introduction

Congratulations on your purchase of the Triplett RHT37 Dual Input Hygro­Thermometer/Psychrometer. This displays humidity, dew point, wet bulb,
temperature and temperature differential. The triple backlit LCD can be
changed to display humidity, temperature, dew point or humidity,
temperature and wet bulb or humidity, temperature and Type K
thermometer. The RHT37 can also display the temperature difference
between Type K T1 and T2 or air temperature and Type K or Type K and
dew point.

Description

METER DESCRIPTION

1. Humidity Sensor & Air Temperature Sensor

2. Triple LCD Display

3. On/Off; Set Mode

4. Min/Max/Average; Reset Min/Max

5. Air, T1, Air-T1, Dew Point

6. T1 probe input

7. T2 probe input

8. T1-T2, T2, T1-Dew Point, Wet Bulb

9. Store Current Reading; Backlight

10. Hold; Recall Mode

11. RS232 port
Note: Battery compartment is located on the rear of

the instrument.

Display Description

1. Air, T1, Air-T1, Dew Point, Low
Battery

2. Temperature °C/°F

3. T2, T1-T2, T1-Dew Point, Wet Bulb

4. Temperature °C/°F

5. Date (month, day, year), Time (24
hour clock)

6. Memory Store/Recall Location

7. Relative Humidity %

8. Maximum, Minimum

9. Hold, Average

Operation

Open the Protective Sensor Cap

Twist the protective sensor cap, located
at the top of the meter, counter­clockwise a quarter of a turn to expose
the sensors.

Turn Power ON or OFF

Press the [ON/OFF] button to turn
power on or off. The meter will perform
a short self-test when turned on.

Taking measurements

1. Hold the probe in the area to be tested.

2. Allow adequate time for readings to stabilize.

3. The Relative Humidity measurement appears in the right display along
with the date and time.

4. Air Temperature appears in the top left display.

5. Wet Bulb is in the lower left display.

6. Pressing the [T1T/DPSEL] button toggles the top left display
between Air temperature, T1 temperature, Air-T1, and DP
(Dew Point).

7. Pressing the [T2▲WB] button toggles the lower left display between
WB (Wet Bulb), T1-T2, T2, and T1-DP (Dew Point).

SETUP

When the meter is off, press and hold the [ON/OFFSET] button for more
than 2 seconds to enter setup mode. Prnt will appear on the display.

3. Selecting temperature units of measure (C/F)

Momentarily press the [T1T/DPSEL] button until “unit” appears in the display.
Press the [MEM] button to toggle between C or F.
Press the [T2▲WB] button to confirm the setting and return to normal
operation.

1. Setting the Date/Time (24 hour clock)

Press the [T1T/DPSEL] button to select Year, Month, Day, Hour and Minute in
sequence.

Press the [MEM] button to change the settings.
Press the [T2▲WB] button to confirm the date/time setting and return to
normal operation.

Data Hold

Press the [RECHOLD] button momentarily to freeze the displayed reading.
The 'HLD' icon will appear on the upper right-hand side of the display.
Press the [RECHOLD] button again to return to normal operation.

Minimum (MN) Maximum (MX) Average (AVG) Function

The MIN/MAX/Average mode allows the user to view only the lowest (MN),
highest (MX) or average readings. Press the [Min/AVRST] button once and
MN appears on the display. The display is now showing the lowest humidity
and temperature readings in memory. Press the [Min/AVRST] button again
and MX appears on the display. The display is now showing the maximum
humidity and temperature readings in memory. Press the [Min/AVRST] button
again to display the average (AVG) readings in memory. To exit the
MIN/MAX/AVG mode, press the [Min/AVRST] button. To clear the current
min/max/avg readings in memory, press and hold the [Min/AVRST] button for
more than two seconds.

Backlight Display

Press the [Min/AVRST] and [MEM] buttons together to turn on the
backlight. It will remain on for ten seconds.

Automatic Power OFF
With the meter off, press and hold down the [ON/OFFSET] +

[RECHOLD] buttons for more than 1 second to enter auto power off

settings.
Press the [MEM] button to select non-sleep (n) or 2, 5, 10, 20, 40 and 60
minutes autosleep.
Press [T2▲WB] to confirm the selection.

Manual Datalogging

Manual datalogging allows the user to store and recall up to 99 readings with
the press of a button.

4. Press the [MEM] button to manually store a single reading into
memory. The display will flash 3 times and the memory location
number will be displayed below the humidity reading.

5. To view stored readings, press and hold the [RECHOLD] button for 2

seconds and “RECALL” will blink next to the memory location number

on the display.

6. Press the [MEM] button to manually increment through the stored
readings.

7. Press [RECHOLD] + [MEM] for more than 1 second to clear the
memory.

8. Press [RECHOLD] for more than 1 second to return to normal
operation.

Note: In RECALL mode, pressing the [Min/AVRST ] button for min/max/avg

readings will auto search the stored readings in memory and display
the minimum, maximum and average values of the stored readings.

RS-232 PC Communications Interface

The meter is equipped with an RS -232 PC interface jack (3.5mm phono) for
connection to a PC for Data Acquisition.

Specifications

Function

Range and Resolution

Accuracy

Humidity

0.0 to 100.0% RH

±3% RH (10 to 90%)

@ 23°C

Temperature (air)

-20 to 50oC (-4.0 to

122.0oF)

±1oC (±1.8oF)

Temperature
(external K)

-200 to 1370oC (-328 to
2498oF)

±(0.3% rdg + 1oC

(1.8oF))

Display

Triple LCD

Sensor Type

Humidity: Precision
capacitance sensor

Internal Temperature:
Thermistor

External Temperature: K-Type Thermocouple

Response Time

60 seconds typical

Dew Point

-68 to 50oC (-90.4 to 122.0oF) (calculated from RH

and Air temperature

measurements)

Wet Bulb

-21.6 to 50oC (-6.88 to 122.0oF) (calculated from

RH and Air

temperature measurements)

Low Battery
Indicator

Yes

Overrange
Indicator

E2 (air) E5 (T1), E8 (T2)

Underrange
Indicator

E3 (air), E6 (T1), E9 (T2)

Operating
Conditions

-20 to 50oC (-4 to 122oF); < 99% RH non-

condensing

Storage
Conditions

-40 to 85oC (-40 to 185oF); <99% RH non-

condensing

Power Supply

4 x 1.5V ‘AAA’ batteries

Battery Life

Approx. 300 hours

Dimensions /
Weight

230 x 57 x 44mm (9 x 2.2 x 1.7”); 153g (5.3 oz.)

Maintenance

Cleaning and storage

1. The meter should be cleaned with a damp cloth and mild detergent
when necessary. Do not use solvents or abrasives.

2. Store the meter in an area with moderate temperature and humidity
(refer to the operating and storage range in the specifications chart
earlier in this manual).

Battery Replacement

When the battery power falls low, the symbol will appear on the

LCD. Replace the four (4) 1.5 ‘AAA’ batteries by removing the rear

battery compartment cover and accessing the battery compartment.
Observe polarity when placing the batteries in the compartment.
Ensure that the compartment cover is securely fastened when finished.

Never dispose of used batteries or rechargeable
batteries in household waste. As consumers, users
are legally required to take used batteries to
appropriate collection sites, the retail store where the
batteries were purchased, or wherever batteries are

Disposal: Do not dispose of this instrument in household waste. The user
is obligated to take end-of-life devices to a designated collection point for
the disposal of electrical and electronic equipment.

Warranty

Triplett / Jewell Instruments extends the following warranty to the original purchaser of
these goods for use. Triplett warrants to the original purchaser for use that the products
sold by it will be free from defects in workmanship and material for a period of (1) one
year from the date of purchase. This warranty does not apply to any of our products
which have been repaired or altered by unauthorized persons in any way or purchased
from unauthorized distributors so as, in our sole judgment, to injure their stability or
reliability, or which have been subject to misuse, abuse, misapplication, negligence,
accident or which have had the serial numbers altered, defaced, or removed.
Accessories, including batteries are not covered by this warranty

sold.

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