General tools RHMG700DL User Manual
14-IN-1 DATA LOGGING
THERMO-HYGROMETER
WITH PIN/PINLESS MOISTURE METER
USER’S MANUAL
RHMG700DL
Please read this manual carefully and thoroughly before using this product.
TABLE OF CONTENTS
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 –4
Key Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Safety Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
What’s in the Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Product Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 –7
Setup Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Install Battery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Operating Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 – 15
Powering On and Off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Selecting a Parameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
General Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 –9
Recalling Stored Readings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Setting Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 – 11
Measuring Moisture Levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 – 12
Checking Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Data Logging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 – 15
Viewing Data Logging Settings . . . . . . . . . . . . . . . . . . . . . . . . . 12 – 13
Changing Data Logging Settings . . . . . . . . . . . . . . . . . . . . . . . . 13 – 14
Clearing Data Logs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 – 15
Starting and Stopping Data Logging . . . . . . . . . . . . . . . . . . . . . . . . . 15
Using the Included Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 – 16
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Operating & Maintenance Tips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Warranty Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Return for Repair Policy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
INTRODUCTION
Thank you for purchasing General Tools & Instruments’ (General’s) RHMG700DL 14-in-1 Data
Logging Thermo-Hygrometer with Pin/Pinless Moisture Meter. Please read this user’s manual
carefully and thoroughly before using the instrument.
The RHMG700DL is a handheld instrument that will prove useful to three broad groups of users:
HVAC/R system installers and technicians, facility maintenance professionals and water damage
restoration contractors.
The first two groups will exploit the meter’s ability to measure, display and store/recall ten
condensation-related parameters: ambient temperature, relative humidity (RH), absolute humidity
(AH), GPP (mixing ratio—in grains per pound or g/kg), dew point, wet bulb temperature, surface
temperature (using an optional “K” type thermocouple probe), condensation temperature (using
an optional “K” type thermocouple probe), atmospheric pressure and vapor pressure. The meter’s
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large, primary readouts of each of the last eight parameters are accompanied by a smaller,
secondary readout of the first parameter: ambient temperature. The ten parameters measured,
monitored and displayed—individually or in pairs—by the RHMG700DL are most valuable in two
applications:
• Environmental monitoring of office buildings, greenhouses, food and equipment storage
facilities, wineries, freezers, shipping containers, HVAC/R installations, computer rooms, labs,
libraries, museums and saunas.
• Electronics manufacturing. Alerts provided by the low RH alarm of the RHMG700DL can
mitigate the risk of damaging high-voltage static discharges.
Water damage remediators will also make use of the RHMG700DL’s ability to calculate an
environment’s mixing ratio (often represented using the unit GPP, or grains per pound). GPP is a
more useful moisture metric than RH to water damage remediators. Using RH alone, a remediator
might unknowingly introduce moist air—with a low RH but a high GPP—during a job’s drying
phase.
Another parameter of interest to water damage remediators is the moisture level of a substance
(typically, wood or building materials). The RHMG700DL can measure this parameter using either
a pinless (non-marring) or pin-type (penetrating) probe; the meter includes both kinds of probe.
Operating in internal moisture mode, the meter uses a non-invasive (pinless) sensor on the back
of the unit to detect moisture up to 3/4 in. (20mm) below the surface of the following materials:
wallboard, masonry, hardwood and softwood. It infers the level of moisture from the material’s
capacitance, which the meter measures by gauging its effect on an electric field that the meter
generates each time it is operated in internal moisture mode.
In internal moisture mode, the meter exploits two physical phenomena to make its
measurements:
1. The linear relationship between a solid material’s moisture level and its dielectric constant—
and therefore its capacitance.
2. The so-called fringing-field effect—the slight spreading of the electric field produced by current
flowing between two electrodes when both electrodes are on the same side of a material.
Behind the back cover of the RHMG700DL are two metal plates. When the meter is powered on,
the plates are given small and opposite charges. The potential difference causes current to flow,
creating a three-dimensional electric field.
When the back of the meter is placed against one side of a material with moisture on or slightly
below its surface, the increased capacitance of the material distorts the electric field to an extent
that can be sensed (as a change in flux over the sensing area) and measured. Displayed readings
reflect the average moisture level of the material between its surface and the electric field’s
maximum penetration of 3/4 in. Moisture closer to the surface has a greater effect on readings
than moisture at the maximum penetration depth.
In external moisture mode, the meter bases its measurements on the relationship between the
moisture content of a material and its electrical conductivity. The wetter a material, the higher its
conductivity. The two replaceable steel pins of the included external probe serve as the
electrodes of a conductance meter optimized for measuring moisture content. The meter displays
measurements in the unit %WME (Wood Moisture Equivalent).
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For hard materials like wood or concrete, the meter’s readings largely reflect surface moisture
content because: 1) Moisture close to a surface has a greater effect on a reading than moisture
deep below it; and 2) The pins of the external probe are only 3/8 in. (10mm) long and cannot be
driven deep into a hard material. For softer materials like soil, paper or powders, readings are
more likely to reflect the average moisture level of the material between its surface and the
penetration depth of the pins (normally far less than 3/8 in.).
The instrument can be set up to sound an alarm if a measured RH or moisture level is above or
below a user-defined setpoint. Finally, the unit can track the maximum or minimum reading of
any parameter over the duration of a measurement session.
The RHMG700DL can store and recall 20 pairs of measurements in internal nonvolatile memory.
It can also log (with date and time stamps) up to 8000 data points internally, for later download to
a PC and display as an Excel-formatted graph or table.
KEY FEATURES
• Measures 1) ambient temperature, 2) relative humidity (RH), 3) absolute humidity (AH, in
mg/L or g/m
3
), 4) GPP (mixing ratio—in grains per pound or g/kg), 5) relative moisture level
using pinless sensor, 6) absolute moisture level using included pin-type probe, 7) dew point,
8) wet bulb temperature, 9) surface temperature (requires optional “K” type thermocouple
probe), 10) condensation temperature (requires optional “K” type thermocouple probe), 11)
atmospheric pressure and 12) vapor pressure
• Stores/recalls 20 pairs of readings in/from on-board nonvolatile memory
• Logs up to 8000 data points internally, for later download and display as Excel-formatted
graph or table on Windows PC using included software, driver and USB cable
• Settable high and low alarms for RH, relative moisture level and absolute moisture level
• Backlit LCD with 3-digit primary readout + 4-digit secondary readout
• Field calibratable in pinless moisture level mode
• Min/Max, Data Hold, and 30-minute Auto Power Off functions
• 1 year limited warranty
SAFETY INSTRUCTIONS
• Do not operate the RHMG700DL in the presence of flammable or explosive gases.
• The steel pins of the external moisture probe are very sharp. When using the probe, be
careful not to stab yourself or anyone else. Remember to replace the protective cap over the
pins when finished using the probe.
WHAT’S IN THE PACKAGE
The RHMG700DL comes in a soft carrying pouch inside a box. Also included in the box or pouch
are a pin-type moisture probe, a sensor protection cap, a PC interface program and driver on a
mini-disc, a USB cable, a “9V” battery and this user’s manual.
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PRODUCT OVERVIEW
Fig. 1 shows the names and locations of all of the controls, connectors and physical structures of
the RHMG700DL. Fig. 2 shows all possible indications on the unit’s LCD. Familiarize yourself with
the labels, positions and functions of all buttons and connectors before moving on to the Setup
Instructions and Operating Instructions.
Fig. 1. The controls and physical structures of the RHMG700DL
A. Humidity/temperature sensor under protective cap
B. Removable hanger tab
C. Socket for optional “K” type thermocouple probe with spade
lugs
D. LCD
E.
LOG/SET
button. Starts and stops data logging.
Also used to view data logging settings.
F.
MAX/MIN
button. For all parameters except moisture level,
pressing button once displays highest reading
since
entering that measurement mode.
Pressing button twice
displays lowest reading
since entering that measurement
mode. Pressing button a third time resumes measurement
and display of same parameter.
Also used to enter alarm set mode.
G.
ZERO
button.
With meter off
, used to disable APO function.
In measurement mode, used to calibrate pinless moisture
(
Moisture Internal
or MI) measurements.
In memory and
data logging modes
, used to clear stored readings and
data.
H.
UNIT
button.
In measurement mode, each press toggles
between Imperial and metric
measurement units for the following parameters: Ambient
Temperature & Dew Point (°F or °C); Absolute Humidity (mg/L or g/m
3
); Mixing Ratio (GPP or
g/kg); Barometric Pressure and Vapor Pressure (mBAR or KPa).
In memory mode
, used to clear
stored readings.
Also used to enter alarm set mode
.
I.
<DN
button.
In measurement mode, each press shifts mode selector one position to the left.
In memory mode, each press decrements record counter
by one digit.
In alarm set mode, each
press decreases alarm setpoint by 0.1%
.
J.
UP>
button.
In measurement mode, each press shifts mode selector one position to the right.
In memory mode, each press increments record counter
by one digit.
In alarm set mode, each
press increases alarm setpoint
by 0.1%.
K.
STORE/ENTER
button.
In measurement mode, stores both displayed readings
in memory
when pressed and held for >2 seconds.
In alarm set mode, saves displayed Hi alarm setpoint
and advances to Lo alarm setting, or saves displayed Lo alarm setpoint and resumes
measurement mode.
In memory mode, exits memory mode
and resumes measurement and
display of last selected parameter.
5
O
A
RHMG700DL
B
C
F
I
M
P
D
G
H
J
K
L
N
E
6
L.
HOLD
button.
With meter off
, pressing button powers it on.
With meter on
, pressing button
briefly freezes primary and secondary readouts; pressing and holding button powers meter off.
M. Jack for included pin-type moisture probe N. Mini-USB jack
O. Pinless moisture sensor (on back) P. Battery compartment (on back)
▼: Mode selector
: Relative humidity mode indicator
: Absolute humidity mode indicator
[Upper] : Dew point mode indicator
: Condensation temperature mode
indicator
: Mixing ratio mode indicator
: Barometric (ambient) pressure mode
indicator
: Vapor pressure mode indicator
: Pinless moisture measurement mode
indicator
: Pin-type moisture mode indicator
: Time setting indicator
: Data logging interval setting indicator
[Upper] : Data logging length setting
indicator
: Data log working group setting indicator
: Clear data logging setting indicator
: Default setting indicator
,
: Alarm limit indicators
: Data logging indicator
: Zero indicator
: Pin/pinless moisture level indicator
, : Maximum & minimum value
indicators
: Data hold indicator
: Primary readout
: Secondary readout
: Recall mode indicator
: Record number indicator
: Condensation level indicators
: USB connection indicator
:Low battery icon
: Probe indicator
[Lower] : Dew point temperature
indicator
L
.
M
N
/HOLD b
out of viewin
Mini USB
L
L
L
L
L
L
L
/HOLD button Press to power the unit on, press HOLD button for 2s to power off,
out of viewing mode.
M
Wood moisture probe interface
N
Mini USB interface
L
CD Display
Fig. 2.
All possible
display
indications
SETUP INSTRUCTIONS
INSTALL BATTERY
To open the battery compartment:
1) Turn the meter over and loosen the single screw securing the battery compartment cover.
Remove the screw and set it aside.
2) Lift the tab at the bottom of the cover in order to remove it and set it aside.
3) Plug the included “9V” battery into the wired socket inside the compartment. The terminals
of the battery and the socket mate in only one way, with the smaller male terminal plugging
into the larger female terminal.
4) Replace the battery compartment cover and reinstall the screw to secure the cover.
OPERATING INSTRUCTIONS
POWERING ON & OFF
To power on the meter
, press the
HOLD
button. By default, the instrument will immediately
begin making and displaying RH (relative humidity) measurements.
Before using the meter
to make measurements, remove the dust cap protecting the
humidity/temperature sensor.
To power off the meter
, press and hold the
HOLD
button for at least 2 seconds. The shutdown
will be announced by two short beeps.
After powering off the meter, replace the sensor protection cap if you do not expect to use the
instrument within the next few hours.
By default, the meter will automatically power itself off if no front-panel button is pressed within
any 30-minute period. The upcoming shutdown will be announced by three beeps of the beeper.
When this Auto Power Off function is active, the term
APO
will appear in the middle of the LCD
(see Fig. 2).
To disable the APO function
, you must power on the meter in a special way, by pressing and
holding the
ZERO
button while pressing the
HOLD
button. When the APO function has been
disabled, the term
APO
will
not
appear on the LCD.
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: Web bulb temperature indicator
,
: Date and Time indicators
: Auto power off enabled indicator
, : Mixing ratio units
, : Absolute humidity units
,
:
Relative humidity unit
: Temperature units
, : Pressure units
:Seconds, minutes, hour, day
indicators
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