General DMM550 User Manual

Download

Page 1

RUGGED TRUE RMS

MULTIMETER

WITH NCV DETECTION

USER’S MANUAL

DMM550

Please read this manual carefully and thoroughly

before using this product.

Page 2

TABLE OF CONTENTS

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Key Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

What's in the Box . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Product Overview . . . . . . . . . . . . . . . . . . . . . . . . 4 –5

Safety Instructions . . . . . . . . . . . . . . . . . . . . . . . 6 –8

Setup Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Install Battery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Operating Instructions. . . . . . . . . . . . . . . . . . . . 9 – 19

General Instructions . . . . . . . . . . . . . . . . . . . . 9 – 12

Ranging Options . . . . . . . . . . . . . . . . . . . . 9 – 10

Holding Readings . . . . . . . . . . . . . . . . . . . . . . 10

Tracking Maximum and Minimum Readings. . 10

Making Relative Measurements . . . . . . . 10 – 11

Disabling Auto Power Off (APO). . . . . . . . . . . . 11

Using the Analog Bar Graph . . . . . . . . . . . . . . 11

Turning on the Backlight . . . . . . . . . . . . . . . . . 12

Measuring AC or DC Current. . . . . . . . . . . . . 12 – 13

Measuring AC or DC Voltage. . . . . . . . . . . . . 13 – 15

Using the Non-contact Voltage Detector

. . 14 – 15

Measuring Resistance . . . . . . . . . . . . . . . . . . . . . 15

Checking for Continuity . . . . . . . . . . . . . . . . . . . . 16

Checking the Integrity of a Diode . . . . . . . . . . . . . 16

Measuring Capacitance . . . . . . . . . . . . . . . . . . . . 17

Measuring Frequency and Duty Cycle . . . . . . . . . 17

Measuring Temperature . . . . . . . . . . . . . . . . 18 – 19

Specifications . . . . . . . . . . . . . . . . . . . . . . . . . 18 – 21

Operating & Maintenance Tips . . . . . . . . . . . . . . . . 21

Warranty Information . . . . . . . . . . . . . . . . . . . 22 – 23

Return for Repair Policy . . . . . . . . . . . . . . . . . . . . . 23

Page 3

INTRODUCTION

Thank you for purchasing General Tools & Instruments’ (General’s) DMM550 Rugged True RMS Multimeter with NCV Detection. Please read this user’s manual carefully and thoroughly before using the instrument.

The DMM550 is designed for use in an industrial setting by HVAC/R contractors, building maintenance technicians, MRO (maintenance, repair and operations) personnel at process and power plants, electricians and electrical/electronic technicians.

KEY FEATURES

• 18 functions, 48 ranges

• Measures AC/DC voltage, AC/DC current, resistance, capacitance, frequency and duty cycle

• Also measures temperature from -58° to 1112°F (-50° to 600°C) with included “K” type stem thermocouple probe

• Checks continuity and diode integrity

• True RMS measurements

• IP54 water/oil/dust protection

• 6 ft. (1.8m) drop-resistant

• Designed to meet CAT III 1000V, CAT IV 600V safety standard

• Auto or manual ranging

• Non-contact voltage (NCV) detection

• Backlit 3-1/2 digit (4,000 count) dual readout LCD

• 40-segment analog bar graph at bottom of LCD

• Hold, Max, Min, Rel (Zero) display options

• 15-minute Auto Power Off (can be disabled)

• 3 year limited warranty

Page 4

WHAT’S IN THE BOX

The meter is supplied inside an illustrated box. Also inside the box are a set of 1000V/10A-rated doubleinsulated test leads with screw-on alligator clips, a “K” type stem thermocouple probe and plug adapter, (1) “9V” battery, a cloth pouch with belt loop, and this user’s manual.

PRODUCT OVERVIEW

Fig. 1 shows the labels and positions of the controls, indicators and physical structures of the DMM550. Fig. 2 shows all possible indications on the LCD. Familiarize yourself with the functions and meanings of these controls, indicators and connectors before moving on to the Setup Instructions and Operating Instructions.

Fig. 1. The controls, indicators and physical structures of the DMM550.

햲

Non-contact voltage (NCV) visual indication (red LED)

햳

LCD

햴

Function buttons:

•

REL

⌬: Multi-function button. Used to 1) Enter

relative measurement mode (see p. 10) and

2) Disable the meter’s Auto Power Off function (see p. 11)

400

DMM550

TRMS

햸

햹

Page 5

• RANGE

: Switches between Auto ranging and Manual

ranging modes (see p. 9)

• MAX/MIN

: Enters Max/Min mode (see p. 10), in which the secondary display shows the largest and smallest values of any parameter since switching to measure it.

• HOLD

: “Freezes” the primary and secondary readouts (but not the analog bar graph at the bottom of the LCD)

• FUNC

: Multi-function button. 1) With the rotary function switch in the , , or position, selects AC or DC voltage (see p. 13) or current (see p. 12); 2) With the rotary function switch in the

Temp

position, selects °F or °C unit (see p. 18);

3) With the rotary function switch in the position, selects resistance measurement, continuity checking or diode integrity verification (see pp. 15 – 16)

•

Turns the backlight on and off

• NCV

: Activates the non-contact voltage sensor

(see p. 14)

햵

Rotary function switch

햶

Input jacks:

uA/mA

jack is used to measure currents

with amplitude <400mA;

10A

jack is used to measure

currents with amplitude from 400mA to 10A

햷

NCV sensor

햸

Battery compartment (on back)

햹 Flip-up stand (on back)

Fig. 2. All possible display indications

Page 6

SAFETY INSTRUCTIONS



Warning



To avoid possible electric shock or personal injury, and to avoid damaging the meter or the equipment under test:

• Do not use the meter in any way not detailed in this manual or the meter's safety features may be compromised.

• Before using the meter, inspect the case. Do not use the meter if it is damaged. Look for cracks or missing plastic. Pay particular attention to the insulation around the connectors.

• 

WARNING

Inspect the test leads for damaged insulation or exposed metal. Check the test leads for continuity. Replace damaged test leads before using the meter.

• Verify the meter’s operation by measuring a known voltage. Do not use the meter if it operates abnormally. Protection may be impaired. When in doubt, have the meter serviced.

• 

WARNING

Do not apply more than the rated voltage,

as marked on the meter, between the and

COM

jacks or between any jack and ground. Also do not input more than the rated current, as marked on the meter, through the

10A

uA/mA

jack.

• 

WARNING

Do not measure voltages above 1000V in

Category III installations.

• 

WARNING

Do not attempt to measure voltage with the rotary function switch in the , , , , or

Temp

position. Never attempt to measure current

with the rotary function switch in the , or

Temp

position.

• Use caution when working with voltages above 42VAC

RMS

, or 60VDC. These voltages pose a shock

hazard.

• Use the proper terminals, function and range for all measurements.

Page 7

• 

WARNING

Do not operate the meter around

explosive gas, vapor, or dust.

• 

WARNING

When using the probes, keep your fingers behind the finger guards. Do not touch the metal probes of the test leads when making a measurement.

• When making connections, connect the black (–) test lead before connecting the red (+) test lead; when disconnecting, disconnect the red (+) test lead before disconnecting the black (–) test lead.

• Disconnect circuit power and discharge all highvoltage capacitors before measuring/testing resistance, continuity, diodes, or capacitance.

• For all DC functions in both auto and manual ranging mode, to avoid the risk of shock due to possible improper reading verify the presence of any AC voltages by first using the AC function. Then select a DC voltage range equal to or greater than the AC range.

• Before measuring current, turn off power to the circuit before connecting the meter.

• Do not operate the meter with the case (or part of the case) removed.

• Use only (1) “9V” battery, properly installed in the battery compartment, to power the meter. Do not use rechargeable batteries.

• Replace the battery as soon as the low battery indicator “ ” appears. Operated with a weak battery, the meter might produce false readings that could lead to electric shock and personal injury.

• Remove the test leads from the meter before opening the meter case or battery compartment.

Page 8

Electrical Symbols Used On the Meter and In This Manual

Symbol Description Symbol Description

AC (Alternating Fuse Current)

DC Double (Direct Current) Insulated

Caution, risk of Risk of danger. electric shock. Important Hazardous information. voltage. Refer to the

manual.

Battery (Low battery) Earth ground when shown on display

Diode Continuity

Beeper

AC or DC Ω Resistance

Capacitance Application and removal

from hazardous live conductors permitted

For measurements made on building equipment such as distribution panels, feeders and short branch circuits, and on lighting systems in large buildings.

Auto Power Off function enabled

CAT IV

For measurements on circuits connected directly to the source of power for a given building (for example, on the cable to the power transformer ahead of a building’s circuit breakers). Very high levels of energy available at CAT IV level make arc flash possible.

Page 9

SETUP INSTRUCTIONS

INSTALL BATTERY

The battery compartment of the DMM550 is located at the back of the meter.

To open the compartment, use a small Phillips-head screwdriver to remove the single screw securing the battery compartment cover/flip-up stand. Be careful not to lose the small screw. Put the cover/stand to the side.

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.

Secure the battery compartment by replacing the cover/stand and reinstalling and tightening the Phillipshead screw.

OPERATING INSTRUCTIONS

GENERAL INSTRUCTIONS

The DMM550 provides several functions that can be applied to measurements and displays of multiple parameters.

Ranging Options

By default, the meter automatically enters Auto Ranging mode when powered on. In this mode, the meter chooses the measurement range that maximizes the resolution of its current, voltage, resistance, capacitance and frequency measurements. The term indicates operation in Auto Ranging mode.

To switch to Manual Ranging for any parameter other than temperature, press the

RANGE

button once. This will make the term disappear and cause the meter to enter the broadest full-scale range available for that parameter (see the Specifications section beginning on p. 18 for a list of the measurement ranges available for each parameter).

Once the meter is in manual ranging mode, each subsequent press of the

RANGE

button reduces the fullscale range by an order of magnitude (a factor of 10). For example, pressing the

RANGE

button with the meter

AUTO

Page 10

operating in the 0 to 400μF full-scale manual range reduces the full-scale range to 0 to 40μF (and improves measurement resolution). The next press of the button reduces the range to 0 to 4μF. When the smallest fullscale range has been reached, the next press of the

RANGE

button switches the meter back to the largest full-

scale manual range for the parameter being measured.

To exit Manual Ranging mode

and return to Auto Ranging

mode, press and hold the

RANGE

button.

Holding Readings

Pressing the

HOLD

button “freezes” the values on both the primary and secondary readouts and causes an icon to appear at the top left of the LCD. Pressing the button again releases the hold and removes the icon. While readings are held, the analog bar graph at the bottom of the LCD continues to track real-time readings of the parameter being measured.

Tracking Maximum and Minimum Readings

Pressing the

MAX/MIN

button once switches the

secondary readout to show the

largest

value of the parameter being measured since entering that measurement mode. The primary display and the analog bar graph at the bottom of the LCD will continue to show real-time readings.

Pressing the

MAX/MIN

button a second time switches the

secondary readout to show the

smallest

value of the parameter being measured since entering that measurement mode. The primary display and the analog bar graph at the bottom of the LCD will continue to show real-time readings.

Pressing the

MAX/MIN

button a third time resumes “normal” display operation, with different values in the primary and secondary readouts.

When the

MAX/MIN

button is pressed, the meter will automatically exit Auto Ranging mode and enter Manual Ranging mode using the full-scale range in effect at that moment.

Making Relative Measurements

Pressing the

REL⌬

button during measurement of current, voltage, resistance or capacitance freezes the value being measured at that instant on the secondary

Page 11

(upper) readout. The term

REL

will appear at the upper left of the LCD to indicate operation in this special mode. In

REL

mode, the primary (lower) readout shows the

difference

between ongoing measurements and the

frozen value.

REL

mode is useful for tracking changes in

dynamic processes or deviations from baseline readings. When the

REL⌬

button is pressed, the meter automatically exits Auto Ranging mode and enters Manual Ranging mode using the full-scale range in effect at that moment.

To exit

REL

mode, press the

REL⌬

button again.

Disabling Auto Power Off (APO)

By default, the meter automatically powers itself off if no front-panel button is pressed within any span of 15 minutes. Fifteen seconds before the end of this 15-minute period, the meter announces that the APO function is about to engage by sounding a sequence of 3 double beeps, followed by a long beep.

Once the APO function has activated and powered the meter off, you can “wake the meter up” simply by turning the rotary function switch to a different position.

The icon on the left side of the LCD indicates that the APO function is enabled. To disable the APO function, you must power on the meter in a special way—by pressing and holding the

REL⌬

button while turning the rotary

function switch to any position other than

OFF

. If the meter is powered on in this way, the icon will not appear. If the meter is left unattended with APO disabled, it will remain powered on until its battery discharges (typically, several days later).

Using the Analog Bar Graph

The bar graph at the bottom of the LCD (see below) provides an analog representation of every measurement shown in digital form on the primary readout above it.

The key feature of the bar graph is its fast response time. It can reflect a change in a measured value 10 times more quickly than the digital readout can. Accordingly, it is useful for tracking parameters that change very rapidly (a voltage or current, for example).

Page 12

Turning On the Backlight

Pressing the button turns on the LCD’s bright white backlight, making measurements much easier to read in dark spaces.

To prevent the backlight from draining the meter’s battery, the backlight automatically extinguishes in 60 seconds.

MEASURING AC OR DC CURRENT



Warning



Do not attempt to measure: 1) currents larger than 400mA through the

uA/mA

jack; 2) currents larger than

10A through the

10A

jack continuously for more than 30 seconds; pause 1 minute after each measurement of such a large current.

Remove power from the circuit to be tested and discharge all capacitors.

(1) Turn the rotary function switch to the , or

position, depending on the current amplitude you expect to encounter. If you are unsure what amplitude to expect, select the position.

(2) Press the

FUNC

button to select either AC or DC current, as indicated by the or display icon on the left side of the LCD.

(3) Before measuring DC currents, press the

REL⌬

button

to reset the DC current measurement baseline to

(4) Plug the black test lead into the black

COM

jack at the

bottom right of the front panel.

(5) Plug the red test lead into the red

10A

uA/mA

jack

at the bottom left of the front panel. Choose the

uA/mA

jack if you have set the rotary function switch

to the or position and the

10A

jack if you have

set the rotary function switch to the position.

(6) Break the circuit and connect the test leads across

the break. Connect the red lead to the higher-voltage side of the break and the black lead to the lowervoltage side.

(7) Re-apply power to the circuit and read the measured

current amplitude on the primary readout. If

O.L

is the

Page 13

reading, the current amplitude exceeds the limit of the selected current measurement mode. If this is the case, move the rotary function switch to the nexthighest position among , and .

Notes:

A. During measurements of AC current, the primary

readout shows the amplitude of the current while the secondary readout in the upper right corner shows the frequency of the current.

B. General’s FX3000 Flex Clamp Adapter makes it

possible to enclose a thick or hard-to reach conductor, a bundle of conductors, or a busbar carrying up to 3000A. The accessory uses induction to convert current readings to millivolt values that can be displayed by the DMM550. For more information or to order, visit www.generaltools.com and enter “FX3000” in the SEARCH box.

MEASURING AC OR DC VOLTAGE



Warning



Do not measure voltage higher than 600V. Doing so may damage the meter’s internal circuitry. If the voltage is over 1000V, the beeper will sound continuously, indicating an over-range measurement.

(1) Turn the rotary function switch to the position. By

default, when the switch is initially set to this position the meter is configured to measure DC voltage (as indicated by the display icon on the left side of the LCD). To measure AC voltage, press the

FUNC

button

to change the icon to .

(2) Plug the black test lead into the front-panel

COM

jack

and the red test lead into the jack.

(3) Touch the black test lead to the lower-potential point

of the circuit under test, and the red test lead to the higher-potential point.

(4) Read the measured voltage on the display. When

measuring DC voltage, if the test leads are reversed a minus sign will appear at the left of the displayed value.

Note: During measurements of AC voltage, the primary readout

shows the amplitude of the voltage while the secondary

Page 14

readout in the upper right corner shows the frequency of the voltage.

Using the Non-contact Voltage Detector

. The DMM550’s NCV detector provides a safe (non-contact) way to check whether a line, cable or AC outlet is “hot” (energized). At the top of the meter (Fig. 1, Callout 6) is an NCV sensor that can detect from a short distance the electromagnetic field created by AC voltage. If voltage is detected, the meter produces audible and visual alarms (a beeping sound, and a flashing red light from an LED near the top of the front panel (Fig. 1, Callout 1)).

Even unloaded AC circuits generate electromagnetic fields. Although these fields are extremely weak, their constantly changing nature means that they generate some current. A sensitive NCV detector can sense this current via induction, in much the same way that a sensitive radio receiver can sense weak radio waves.

NCV detectors cannot detect DC voltages, such as those present in automotive electrical systems. In addition, the DMM550 typically cannot detect 120VAC from a distance of more than 0.25 in. (6.2mm), and never through a wall or metal conduit.



Warning



The NCV detector in the DMM550 is designed to indicate the presence of AC voltage with an amplitude of 110VAC

RMS

or greater. However,

do not

assume that the absence of a positive indication means that the circuit under test is de-energized (not “hot”). Do not rely solely on NCV detection to determine the presence of voltage in a wire. NCV detection may be affected by the design of the outlet, the type of wiring insulation and other external factors. Also be aware that “false positive” NCV indications may be triggered by connection of the meter’s test leads to a voltage source or by external interference from a flashlight, motor or other electrical device.

Whenever you have reason to suspect that a line or outlet is “hot”, confirm your suspicion by measuring the voltage of the line or outlet using the test leads with the meter’s rotary function switch in the position.

Page 15

To check whether a line, cable or AC outlet is “hot”

(energized), touch it with the top of the meter or bring the top within 1/4 inch of it while pressing and holding the front-panel

NCV

button. If the beeper sounds repeatedly and the red LED flashes rapidly, the line or outlet is energized.

The NCV detector works with the rotary function switch in any position.

MEASURING RESISTANCE



Warning



To avoid electrical shock or damage to the meter when measuring the resistance or checking the continuity of a circuit, make sure power to the circuit is turned off and all capacitors are discharged.

(1) Turn the rotary function switch to the position. By

default, when the switch is initially set to this position with the test leads not plugged in the meter will automatically 1) enter resistance measurement (indicated by the term

MΩ

at the lower right of the

LCD) and Auto Ranging modes and 2) display

O.L

(indicating an open circuit) on the primary readout.

(2) Plug the black test lead into the front-panel

COM

jack

and the red test lead into the jack.

(3) Measure the resistance by touching or clipping the

test leads to the desired test points of the circuit or to the terminals of a component, as shown below.

(4) Read the measured resistance on the display. If the

measured resistance value is greater than 40MΩ,

O.L

will appear on the primary readout. The meter will take a few seconds to stabilize when measuring resistances greater than 1MΩ.

RED TEST LEAD

BLACK TEST LEAD

Page 16

CHECKING FOR CONTINUITY

(1) Turn the rotary function switch to the position.

Press the

FUNC

button once to select the continuity check function. Until the test leads are plugged in, the primary readout will show

OL.

, with the icon of a

continuity beeper ( ) above it.

(2) Plug the black test lead into the front-panel

COM

jack

and the red test lead into the jack.

(3) Touch or clip the test leads to any two points of the

circuit. The resistance between those two points will be shown on the primary readout. If the resistance is <50Ω, the beeper will sound continuously. If there is no continuity (an open circuit or a resistance greater than 600Ω between the two points),

O.L

will appear

on the primary readout.

CHECKING THE INTEGRITY OF A DIODE

(1) Turn the rotary function switch to the position.

Press the

FUNC

button twice to select the diode check function. Until the test leads are plugged in, the primary readout will show

.OL

, with the icon of a

diode ( ) above it.

(2) Plug the black test lead into the front-panel

COM

jack

and the red test lead into the jack.

(3) Connect the red test lead to the anode (positive

terminal) of the diode to be tested and the black test lead to its cathode (negative terminal), as shown below.

(4) Read the diode’s forward bias voltage drop on the

display. A silicon diode typically has a forward bias voltage of 0.7V. A germanium diode typically has a forward bias voltage of 0.3V. A

reading in both

directions indicates a shorted diode. An

.OL

reading indicates an open diode. In either case, the diode is defective and should be replaced.

RED TEST LEAD

BLACK TEST LEAD

Page 17

MEASURING CAPACITANCE

To avoid possible damage to the meter or other equipment, turn off the power source and discharge all high-voltage capacitors.

(1) Disconnect the capacitor from power. (2) Short the capacitor’s terminals to discharge it. (3) Disconnect any resistors between the terminals of the

capacitor.

(4) Turn the rotary function switch to the position.

Until the test leads are plugged in, the primary readout will show

0.000 nF

(5) Plug the black test lead into the front-panel

COM

jack

and the red test lead into the jack.

(6) Connect the test leads to the terminals of the

capacitor.

(7) Read the measured capacitance on the display.

MEASURING FREQUENCY AND DUTY CYCLE

As described earlier, the DMM550 automatically measures the frequency of measured AC currents and voltages and displays them on the secondary readout. However, the range of frequencies that can be measured and displayed in this way is limited to 10Hz to 1kHz. Using the

Hz%

position of the rotary function switch expands the range of measurable frequencies to 10Hz to 40MHz, while providing better measurement resolution (via multiple ranges) and greater measurement accuracy.

To measure frequency

in this way:

(1) Turn the rotary function switch to the

Hz%

position.

(2) Plug the black test lead into the front-panel

COM

jack

and the red test lead into the jack.

(3) Touch or clip the test leads to the voltage source or

between loads.

(4) Read the measured frequency on the primary readout

and the duty cycle (as a percentage) on the secondary readout.

Page 18

SPECIFICATIONS

Parameter or Feature/Function Attribute

AC voltage (True RMS) Measurement ranges

Measurement accuracy

Overload protection

DC voltage Measurement ranges

Measurement accuracy

Overload protection

AC current (True RMS) Measurement ranges

Measurement accuracy

Overload protection

DC current Measurement ranges

Measurement accuracy

Overload protection

Resistance Measurement ranges

Measurement accuracy

Frequency (with rotary function Measurement ranges switch in Hz% position)

Measurement accuracy Overload protection

MEASURING TEMPERATURE

To measure the temperature of a solid, liquid or gas: (1) Turn the rotary function switch to the

Temp

position. The primary readout will show spurious readings until a thermocouple probe is plugged into the meter’s front-panel jacks.

(2) Plug the included plug adapter into the red and black

jacks at the bottom front of the meter. Make sure to insert the + (positive) plug of the adapter into the

jack and the

COM

plug into the

COM

jack.

Page 19

±(1.5% of reading + 5 digits) in other ranges

RMS

in 400mV range; 1000VAC

RMS

in other ranges

±(0.5% of reading + 5 digits) in other ranges

RMS

in 400mV range; 1000VDC

RMS

in other ranges

+ 5 digits) in other ranges

position; 10A/1000V fuse with rotary function switch in position

+ 5 digits) in other ranges

position; 10A/1000V fuse with rotary function switch in position

±(0.8% of reading + 5 digits) in other ranges

RMS

(3) Plug the included “K” type thermocouple (or a

different “K” type thermocouple) into the adapter. Make sure to insert the slightly wider blade of the thermocouple into the – (negative) slot of the adapter.

(4) To measure a surface temperature, firmly attach the tip

of the thermocouple to the surface. To measure the temperature of a liquid or gas (including ambient air), make sure that the tip of thermocouple is within the fluid.

(5) Read the measured temperature on the primary

readout. Use the

FUNC

button to toggle between

°F and °C units.

Page 20

Parameter or Feature/Function Attribute

Frequency (with rotary function switch Measurement ranges in position)

Measurement accuracy

Capacitance Measurement ranges

Measurement accuracy

Continuity Open circuit voltage

Threshold

Diode integrity Reverse DC voltage

Forward DC current

Duty cycle Measurement range

Measurement accuracy/ resolution

Temperature Measurement range

Measurement accuracy (excluding thermocouple)

Overload protection level in resistance, frequency, continuity, diode integrity and capacitance modes

Input impedance Sampling time

Safety rating Water/dust/oil protection level Display No. of digits

Maximum count Auto power off trigger Operating temperature Storage temperature Maximum altitude Power source Dimensions Weight (including battery)

Note:

Accuracy values are stated for an operating temperature between 64° and 82°F (18° and 28°C). All accuracy specifications must be derated (increased) by 5.5% for each degree F of operating temperature outside this range.

For example, an accuracy specification of ±3% between 64°F and 82°F would be derated to:

Page 21

±(3% of reading+ 3 digits) in other ranges

≤ 50Ω

RMS

except AC and DC current (1sec for LCD and 400msec for analog bar graph)

6.9 x 3.3 x 2.1 in. (175 x 85 x 52mm)

•

±3.165%

(±3% + (3% x 5.5% x 1))

for operation at 63°F and 83°F

(one degree outside the range)

•

±3.33%

(±3% + (3% x 5.5% x 2))

for operation at 62°F and 84°F

(two degrees outside the range)

•

±3.495%

(±3% + (3% x 5.5% x 3))

for operation at 61°F and 85°F

(three degrees outside the range) · etc.

Page 22

OPERATING & MAINTENANCE TIPS

When the icon appears at the upper left of the LCD, it’s time to replace the “9V” battery that powers the meter (although measurements will remain valid for several hours after the icon first appears). To replace the battery, follow the instructions on p. 9.

Do not operate the DMM550 in the presence of a flammable or explosive gas or near an arc welder or induction heater.

After subjecting the meter to a large change in ambient temperature, wait at least 30 minutes before making measurements to guarantee the accuracy of readings.

Remove the battery when storing the meter or when you do not expect to use it for an extended period of time (months rather than weeks).

Do not disassemble the DMM550 or immerse it in water.

WARRANTY INFORMATION

General Tools & Instruments’ (General’s) DMM550 Rugged True RMS Multimeter with NCV Detection is warranted to the original purchaser to be free from defects in material and workmanship for a period of three years. Subject to certain restrictions, General will repair or replace this instrument if, after examination, the company determines it to be defective in material or workmanship. The warranty period begins on the date of purchase. You are encouraged to register your product online. General will extend your warranty an additional 60 days if you register at www.generaltools.com/ProductRegistry.

This warranty does not apply to damages that General determines to be from an attempted repair by nonauthorized personnel or misuse, alterations, normal wear and tear, or accidental damage. The defective unit must be returned to General Tools & Instruments or to a General-authorized service center, freight prepaid and insured.

Page 23

Acceptance of the exclusive repair and replacement remedies described herein is a condition of the contract for purchase of this product. In no event shall General be liable for any incidental, special, consequential or punitive damages, or for any cost, attorneys’ fees, expenses, or losses alleged to be a consequence of damage due to failure of, or defect in any product including, but not limited to, any claims for loss of profits.

RETURN FOR REPAIR POLICY

Every effort has been made to provide you with a reliable product of superior quality. However, in the event your instrument requires repair, please contact our Customer Service to obtain an RGA (Return Goods Authorization) number before forwarding the unit via prepaid freight to the attention of our Service Center at this address:

General Tools & Instruments 80 White Street New York, NY 10013 212-431-6100

Remember to include a copy of your proof of purchase, your return address, and your phone number and/or e-mail address.

Page 24

GENERAL TOOLS & INSTRUMENTS

80 White Street

New York, NY 10013-3567

PHONE (212) 431-6100

FAX (212) 431-6499

TOLL FREE (800) 697-8665

e-mail: sales@generaltools.com

www.generaltools.com

DMM550 User’s Manual

Speciﬁcations subject to change without notice

NOTICE - WE ARE NOT RESPONSIBLE FOR TYPOGRAPHICAL ERRORS.

MAN# DMM550

7/9/14

General Tools & Instruments

GeneralToolsNYC