General Tools CMR35 User Manual
WIRELESS MULTI-NODE DATA LOGGING
TRUE RMS CLAMP MULTIMETER SYSTEM
USER’S MANUAL
CMR35 SERIES
CMR35–910MHz
CMR35A–912.4MHz
Please read this manual carefully and thoroughly before using this product.
Transmitter
Receiver
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TABLE OF CONTENTS
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Key Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
What’s in the Case . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Product Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 – 6
Operating Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 – 29
Making Basic Measurements with the Transmitter . . . . . . . . . . . . . . . . . . . . . . . . 7
Measuring Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 – 8
Measuring Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 – 9
Measuring Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Testing Diodes and Checking Continuity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 – 10
Measuring Frequency. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 – 11
Making Relative Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Using the Receiver with the Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Setting the Transmitter’s Transmission Span and ID Code (Channel) . . 12 – 15
Operating the Receiver. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 – 21
Reading, Holding, Storing and Recalling Data . . . . . . . . . . . . . . . . . . . . 16 – 18
Setting Alarms and Setpoints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 – 19
Setting the Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Setting the Receiver’s Transmission Span and ID Code (Channel) . . . . 20 – 21
Data Logging with a Computer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 – 29
Installing the Software and a USB Driver . . . . . . . . . . . . . . . . . . . . . . . . 22 – 23
Verifying the Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Using the Software. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 – 29
Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 – 32
FCC Radio Frequency Interference Compliance Disclosure . . . . . . . . . . . . . . . . . . . . . 33
Operation and Maintenance Tips. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Optional Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Warranty Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Return for Repair Policy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
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INTRODUCTION
Thank you for purchasing General Tools & Instruments’ CMR35 Series Wireless Data
Logging Clamp Multimeter System. Please read this user’s manual carefully and
thoroughly before using the instrument.
There are two CMR35 systems: The CMR35 system operates at 910MHz and the
CMR35A system operates at 912.4MHz. The basic CMR35 system consists of one
CMR35T clamp meter/ transmitter, one CMR35R data logging receiver (operating at the
same frequency), a USB cable and an installation CD containing data logging software
and a set of USB drivers. Up to six transmitters on different channels can be interfaced
to one receiver operating at the same frequency. The system is designed for use by
industrial maintenance, repair and operations (MRO) professionals.
Used alone or with the receiver, the multimeter’s clamp-type transmitter can measure AC
or DC voltages up to 600 Volts, AC or DC currents up to 600 Amperes, electrical resistances
up to 4MΩ, and the frequency of AC voltages and currents up to 100 kHz. Autoranging is
automatic for all measurements. The transmitter can also verify the integrity of diodes and
perform yes/no checks of continuity between any two points of a circuit.
When a transmitter and receiver are wirelessly connected—at a maximum distance of
328 ft. (100m), with no obstructions in between—measurements made by the trans mitter
can be displayed remotely and in real time on the receiver’s display. Measure ments also can
be time-stamped by the included data logging software and transferred from the receiver to
a Windows
™
computer via a USB cable. As the computer stores the measurements, they can
be viewed in the software’s Monitor window in real time. Measurement logs also can be
viewed and saved on the computer as tabular or graphical data.
The CMR35 system is powered by four “AA” batteries (two each for the transmitter
and receiver).
SAFETY PRECAUTIONS
• WARNING
To prevent electrical shock, fire or damage to the multimeter:
• Never attempt to measure voltages above 600 Volts or currents above 600 Amperes.
• Make sure the transmitter’s function switch is in the correct position for the
parameter to be measured.
• Check that the transmitter’s probes fit snugly in their jacks whenever using them to
make measurements.
• Keep your hands under the guard ring (see Fig. 1) when using the clamp.
• Before switching functions, remove the probes from the circuit under test, and
remove conductors from the jaws of the clamp.
• Before conducting resistance tests, make sure the power to the circuit under test
has been switched off.
• Never use the multimeter in the rain or snow, or with wet hands.
• Do not use the transmitter if its case or probes have been cracked or damaged.
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KEY FEATURES
• Measures AC and DC voltages, AC and DC currents, resistances, and frequency of
AC voltages and currents
• AC and DC voltage and current measurements are “true RMS” readings
• Includes software and USB cable that connect receiver to a PC, enabling
measurements from up to six transmitters to be displayed, logged (stored on)
an SD card, and viewed in Excel on a Windows computer
• Software also can calculate electricity (power) charges for up to six loads
(single-phase or 3-phase motors, heaters or other heavy loads)
• Autoranging
• Supports setting of Hi and Lo alarm setpoints
• Tests diodes and performs continuity checks
• Wireless receiver works at up to 333 ft. (100m) with no objects between it
and transmitter
• Stores and recalls minimum and maximum readings
WHAT’S IN THE CASE
The two main components of the CMR35 Series system—the clamp meter/transmitter
(CMR35T transmitter) and the data logging receiver (CMR35R receiver)—come in a
protective hard carrying case along with a pair of probes, four “AA” batteries (two
each for the transmitter and receiver), a USB cable, an installation CD containing
Excel-compatible data logging software and a USB driver, and this user’s manual.
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PRODUCT OVERVIEW
Before using the transmitter and receiver together, learn how to make some basic
measurements using the transmitter unit alone. To begin, familiarize yourself with
Figures 1 and 2. Fig. 1 shows the transmitter unit’s controls, indicators and jacks. Fig. 2
shows the symbols used by the transmitter’s liquid-crystal display, as well as their
positions.
햲 Clamp
햳 Clamp tips/opening
햴 Guard ring
햵 Clamp trigger
햶 Function switch
햷 HOLD button
햸햹REL./SEL. button
햺 TX ON button
햻 FUNCTION button
햽 SET button
햾 Nameplate
햿 COM (negative or ground)
input jack
헀 쏋+ (positive) input jack
헁 Liquid-crystal display
Fig. 1. The transmitter’s controls, indicators and jacks
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Fig. 2. Symbols used on the transmitter’s liquid-crystal display
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Symbol Description
Transmission ID code (Channel) setting
Antenna blinking while in the process of transmitting
Transmission span selection; options are
2, 10, 30, 60, and 120 seconds
Lit in DC voltage measurement mode
Lit in AC voltage measurement mode
Lit when measuring negative polarity
Autoranging on indicator
Lit in continuity check mode
Lit in diode check mode
Data hold indicator
Lit in relative mode or when zeroing display
Lit when battery voltage is low
Lit in frequency measurement mode
Unit of resistance measurement
Unit of voltage measurement
Unit of current measurement
Measured value
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OPERATING INSTRUCTIONS
MAKING BASIC MEASUREMENTS WITH THE TRANSMITTER
As you make measurements, be aware that pressing the HOLD button on the transmitter
(callout 6 of Fig. 1) temporarily stores (memorizes) the displayed reading. This feature
comes in handy when making measurements under low-light conditions or in tight
spaces (under counters, in crawl spaces or attics, or inside electrical panels) where the
display is out of sight. In these cases, press the HOLD button to freeze the reading
(causing the letters “D-H” to appear on the top line of the display). Then move the
transmitter to where its display can be read more easily. To release the held reading,
press the HOLD button again.
MEASURING CURRENT
To measure the AC current flow through a conductor, move the function switch to the
A ~position, squeeze the clamp trigger to open the clamp, and place one conductor only
in the center of the clamp’s jaws, as shown in the following figure. Read the value once
it stabilizes.
It is good practice to measure the
current carried by the “hot” line
(usually a black or red wire).
Measurements of current through
the return or neutral conductor
(usually a white wire) may be
misleading because the return may
be used by other circuits.
To measure the current drawn by an
appliance with a fixed power cord,
General recommends using an
industry-standard AC line splitter, as
shown in the following figure. To
purchase an AC line splitter from
General, see p. 31.
In AC current measurement mode, the
CMR35T selects a 0 to 400A measurement
range unless the input is greater than 400A.
In this case, the unit automatically switches
to a full-scale range of 0 to 600A.
When you have finished making measure ments, move the function switch to the
OFF position.
To measure the DC current flow through a
conductor, move the function switch to the
position, squeeze the clamp trigger to
open the clamp, and place one conductor
only in the center of the clamp, as shown in the earlier figure.
7
BLACK OR
RED (HOT)
WIRE
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In DC current measurement mode, the CMR35T selects a 0 to 400A measurement range
unless the input is greater than 400A. In this case, the unit automatically switches to a
full-scale range of 0 to 600A.
Read the value after it stabilizes. If the symbol appears at the left of the measured
value, as shown in Fig. 2, the current flow is opposite the direction indicated by the
polarity marks on the clamp. To reverse the flow, unclamp the meter, rotate the clamp
180º, and then reclamp the jaws around the line.
When you have finished making measurements, move the function switch to the OFF
position.
MEASURING VOLTAGE
To measure the DC voltage between two points in a circuit, move the function switch
to the position. Press the REL./SEL. button until the symbol does not appear
at the left of the display. Plug the rubber-covered end of the black probe into the COM
terminal of the transmitter unit and the rubber-covered end of the red probe into the
unit’s terminal. Then touch the metal ends of the black and red probes to the points
whose potential difference you wish to measure.
• WARNING
• To avoid exposing yourself to a harmful or fatal voltage and damaging the
transmitter, make sure that the potential you are attempting to measure is less
than 600VDC.
As in current measurement mode, the CMR35T automatically chooses the narrowest
measurement range that includes the tested value. The five available full-scale ranges
are 0 to 400mV, 0 to 4V, 0 to 40V, 0 to 400V, and 0 to 600V.
Read the measured value once it stabilizes. If the symbol appears to the left of the
value, the measured voltage is negative. When you have finished making
measurements, move the function switch to the OFF position.
To measure the AC voltage between two points in a circuit, move the function switch
to the position. Press the REL./SEL. button (callout 7/8 of Fig. 1) until the
symbol appears at the left of the display. Plug the rubber-covered end of the black probe
into the COM jack of the transmitter (callout 13 of Fig. 1) and the rubber-covered end of
the red probe into the transmitter’s jack (callout 14). Then touch the metal ends of
the black and red probes to the points whose potential difference you wish to measure.
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• WARNING
• To avoid exposing yourself to a harmful or a fatal voltage and damaging the
transmitter, make sure that the potential you are attempting to measure is less
than 600VAC.
As in current measurement mode, the CMR35T automatically chooses the narrowest
measurement range that includes the tested value. The four available full-scale ranges
are 0 to 4V, 0 to 40V, 0 to 400V, and 0 to 600V.
Read the measured value once it stabilizes. When you have finished making measure ments, move the function switch to the OFF position.
MEASURING RESISTANCE
To measure the resistance between two points of an electrical or electronic circuit, first
make sure that the circuit you are measuring is not carrying any current. Then move the
function switch to the Ω / position. The display should then read “O.L”, with
the symbol “MΩ” at the upper right.
Plug the rubber-covered end of the black probe into the COM jack of the transmitter and
the rubber-covered end of the red probe into the jack. Then touch the metal ends of
the black and red probes to the points between which you wish to measure the
resistance. To avoid affecting the measurement, make sure not to touch the metal tip of
either probe.
The CMR35T automatically chooses the narrowest measurement range that includes the
tested resistance value. The six available full-scale ranges are 0 to 400Ω, 0 to 4kΩ, 0 to
40kΩ, 0 to 400kΩ, 0 to 4MΩ, and 0 to 40MΩ
Read the measured value once it stabilizes. When you have finished making resistance
measurements, move the function switch to the OFF position.
TESTING DIODES AND CHECKING CONTINUITY
To test the integrity of a diode, move the function switch to the Ω /
position. Press the REL./SEL. button until the symbol appears in the top row of the
display, as shown in Fig. 2. Plug the rubber-covered end of the black probe into the COM
jack of the transmitter and the rubber-covered end of the red probe into the jack.
The CMR35T supports both forward-bias and reverse-bias diode testing. To perform a
forward-bias test, first make sure that the diode you are measuring is not carrying any
current. Then touch the tip of the red probe to the diode’s anode (+ lead) and the tip of
the black probe to the diode’s cathode (- lead), as shown in part A of the figure on
page 10.
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A “good” silicon diode should produce a reading of 0.5 to 0.7V. A “good” GE diode
should produce a reading of 0.2 to 0.3V. If the reading is close to “0”, the diode is shortcircuited. If the display reads “OL”, the diode is open-circuited.
To perform a reverse-bias test, touch the tip of the red probe to the diode’s cathode
(- lead) and the tip of the black probe to the diode’s anode (+ lead), as shown in part B
of the figure above.
If the diode is “good”, the display will read “OL”. If it is “bad”, the display will show a
voltage level.
When you have finished using the clamp meter for diode testing, move the function
switch to the OFF position.
To check the continuity of a circuit between two points, first shut off all current
flowing through it to avoid damaging the multimeter in one of its most sensitive modes.
Move the function switch to the Ω / position and press the REL./SEL. button
until the symbol appears at the lower left of the display. Then plug the rubbercovered end of the black probe into the COM jack of the transmitter and the
rubber-covered end of the red probe into the jack.
Then touch the metal ends of the black and red probes to the points between which you
wish to check for continuity. If there is continuity between the points, the beeper will
sound and the reading on the display will be less than 100Ω.
When you have finished making continuity checks, move the function switch to the OFF
position.
MEASURING FREQUENCY
To measure the frequency of an AC voltage or current, move the function switch to
the Hz position. Plug the rubber-covered end of the black probe into the COM jack of the
transmitter and the rubber-covered end of the red probe into the jack.
10
RED PROBE
BLACK PROBE
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• WARNING
• To avoid exposing yourself to a harmful or a fatal voltage and damaging the
transmitter, make sure that the AC voltage or current whose frequency you are
measuring has an amplitude of less than 600V.
As in current measurement mode, the CMR35T automatically chooses the narrowest
measurement range that includes the tested value. The six available full-scale ranges
are 0 to 5Hz, 0 to 50Hz, 0 to 500Hz, 0 to 5kHz, 0 to 50kHz, and 0 to 100kHz.
Read the measured value once it stabilizes. When you have finished making frequency
measurements, move the function switch to the OFF position.
MAKING RELATIVE MEASUREMENTS
Pressing the transmitter’s REL./SEL. button (callout 7/8 of Fig. 1) while the transmitter is
measuring AC or DC current flow lights the
쏋
REL symbol on the top line of the
transmitter’s display (see Fig. 2). When this mode—called relative measurement
mode—is activated, the transmitter will display the difference between the values of
successive inputs.
For example, if the transmitter was measuring 10 Amperes when the REL./SEL. button
is pressed and then is connected to a line carrying 15 Amps, the transmitter’s display
will read 5A (the difference between 15A and 10A). If the transmitter’s clamp or probes
are then switched to a line carrying 50 Amps, the display will read 40 Amps (50A minus
the first input value, 10A). A series of relative measurements can be carried out
indefinitely.
Pressing the REL./SEL. button when the transmitter is operating in AC or DC current
measurement mode also deactivates the autoranging function. This causes the AUTO
RANGE text to disappear from the transmitter’s display and sets the transmitter’s
measurement range to a fixed value—the lowest full-scale value that can accommodate
the value being measured when the REL./SEL. button was last pressed (10A in the
above example). If the relative value exceeds this fixed value, the display will read “OL”.
To exit relative measurement mode, press the REL./SEL. button again to make the
쏋
REL
symbol disappear from the top line of the transmitter’s display. To reactivate the
autoranging function, move the function switch to the OFF position, and then to the
position corresponding to the next type of measurement you wish to make.
The REL./SEL. button also has a secondary function; zeroing the transmitter’s display in
DC current measurement mode. If the display shows a residual reading before the jaws
of the clamp are placed around a conductor or before the transmitter’s leads are
connected to a circuit, pressing the REL./SEL. button will “zero out” the display and
deactivate the autoranging function.
As explained earlier, to exit relative measurement mode press the REL./SEL. button
again to make the
쏋
REL symbol symbol disappear. To reactivate autoranging, move the
function switch first to the OFF position and then to the desired measurement position.
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