275
Digital Clamp-on
Meter Instruction Manual
TABLE OF CONTENTS
A. INTRODUCTION
1. Congratulations ..........................3
2. Product Description....................3
3. Declaration of Conformity ..........4
B. SAFETY CONSIDERATIONS ..............5
C. TECHNICAL DATA
1. Features and Benefits..................6
2. Product Applications ..................7
3. Specifications..............................8
D. MEASUREMENT TECHNIQUES
1. Controls and Functions ............12
2. Step by Step Procedures: ........14
E. OTHER FEATURES ..........................24
F. APPLICATION NOTES ......................29
G. TROUBLE SHOOTING GUIDE ..........34
H. MAINTENANCE ................................35
I. ACCESSORIES ................................36
2
A. INTRODUCTION
1. Congratulations!!
Thank you for purchasing TPI products. The 275 is easy
to use and is built to last. It is backed by a 3 year limited warranty. Please remember to complete and return
your product warranty registration card.
2. Product Description
The slim design 275 is a hand-held, autoranging
clamp-on DMM. Extra large numerals, DC amps,
min/max, capacitance, DC microamps and duty cycle are
just a few of the features of the 275. An affordable
choice, the 275 offers measurements in all basic electrical functions with additional advanced features like noncontact voltage.
The 275 comes complete with the following accessories:
Carrying Pouch
Test Lead Set
Temperature Probe
Instruction Manual
Battery & Fuse
3
3. EC Declaration of Conformity
This is to certify that TPI Model 275 conforms to the
protection requirements of the council directive
89/336/EEC, in the approximation of laws of the member
states relating to Electromagnetic compatibility and
73/23/EEC. The Low Voltage Directive by application of
the following standards:
EN 50081-1 1992 Emissions Standard
EN 50082-1 1992 Immunity Standard
EN 61010-1 1993 Safety Standard
EN 61010-2-031 1995 Safety Standard
EN 61010-2-032 1995 Safety Standard
To ensure conformity with these standard, this instrument must be operated in accordance with the instructions and specifications given in this manual.
CAUTION: Even though this instrument complies with
the immunity standards, it’s accuracy can be affected
by strong radio emissions not covered in the above
standards. Sources such as hand-held radio transceivers, radio and TV transmitters, vehicle radios and
cellular phones generate electromagnetic radiation
that could be induced into the test leads of this instrument. Care should be taken to avoid such situations or
alternatively, check to make sure that the instrument is
not being influence by these emissions.
CAUTION: Please follow manufacturers test procedures whenever possible. Do not attempt to measure
unknown voltages or components until a complete
understanding of the circuit is obtained.
4 5
B. SAFETY CONSIDERATIONS
WARNING: Please follow manufacturers test
procedures whenever possible. Do not attempt to
measure unknown voltages or components until a
complete understanding of the circuit is obtained.
GENERAL GUIDELINES
ALWAYS
• Test the 275 before using it to make sure it is
operating properly.
• Inspect the test leads before using to make sure there
are no breaks or shorts.
• Double check all connections before testing.
• Have someone check on you periodically if
working alone.
• Have a complete understanding of the circuit
being measured.
• Disconnect power to circuit, then connect test leads to
the 275, then to circuit being measured.
NEVER
• Attempt to measure unknown high voltages.
• Attempt to measure DC microamps with the meter in
parallel to the circuit.
• Connect the test leads to a live circuit before
setting up the instrument.
• Touch any exposed metal part of the test lead assembly.
INTERNATIONAL SYMBOLS
CAUTION: RISK OF ELECTRIC SHOCK
AC (Alternation Current)
DC (Direct Current)
REFER TO INSTRUCTION MANUAL
GROUND
DOUBLE INSULATION
EITHER DC OR AC
C. TECHNICAL DATA
1. Features and Benefits
Agency Meets CE and IEC 1010.
Analog Bar Displays rapidly changing input
Graph signals.
NCV Non-contact voltage detection. Detect
the presence of voltage without contacting the circuit.
P-H Captures min / max peak.
MAX/MIN Records Min/Max readings for all
functions and ranges.
REL Measurements made are displayed
relative to a stored value.
Auto Off Automatically powers off after 30
minutes of inactivity.
6 7
2. Product Applications
Perform the following tests and/or measurements with
the 275 and the appropriate function:
HV
AC/R
DCmV • Thermocouples in furnaces.
ACA • Heat anticipator current in thermostats.
ACV • Line voltage.
ACV or DCV • Control circuit voltage.
DCµµA • Flame safegaurd control current.
OHMS • Compressor winding resistance.
OHMS • Continuity of wiring.
CAP • Motor start and run capacitors.
ACA • Motor and compressor start up current.
Hz • Frequency on controls and line voltage.
TEMP • Air duct temperatures.
ALL • Bar graph to indicate rapid fluctuations.
ELECTRICAL
ACV • Measure line voltage.
ACA • Measure line current.
OHMS • Continuity of circuit breakers.
DCV • Voltage of direct drive DC motors.
ACA • Start up current of motors, relays,
contactors and transformers.
ELECTRONIC
ACV • Measure power supply voltage.
ACA • Measure power supply current.
OHMS • Continuity of circuit breakers and fuses.
3. Specifications
IEC 1010 Over Voltage:
CAT II - 1000V
CAT III - 600V
Pollution Degree 2
Temperature for gauranteed accuracy: 23ºC +
UL 3111 Pending
5ºC
DC VOLTS
Range Res. Accuracy
110mV 0.1mV
1V 0.001V +/-(0.5% of reading + 2 digits) 10MΩ
11V 0.01V Overload Protection:
110V 0.1V 600VDC or AC RMS
600V 1V
AC VOLTS
Range Res. Accuracy
110mV 0.1mV
1V 0.001V
11V 0.01V
110V 0.1V
600V 1V
(45Hz to 100Hz Frequency Response 400mV Range)
(45Hz to 450Hz Frequency Response All Other Ranges)
+/-(1.2% of reading + 5 digits) Impedance:
+/-(1.2% of reading + 3 digits) 10MΩ
+/-(1.5% of reading + 3 digits) 600VDC or AC RMS
(45Hz to 100Hz Frequency Response 200A to 400A)
Impedance:
Overload Protection:
AC AMPS (45Hz to 450Hz Frequency Response Below 200A)
Range Res. Accuracy
110A 0.01A
400A 0.1A e
+/-(3.0% of reading + 5 digits)
8
DC Microamps
Range Res. Accuracy
110uA 0.01µA
1100uA 0.1µA 0.5A / 600V Fusee
* DC microamps are measured with the test leads in series with
the circuit under test.
+/-(0.8% of reading + 2 digits) Overload Protection:
DC AMPS
Range Res. Accuracy
110A 0.01A
400A 0.1A e
+/-(3% of reading + 10 digits)
OHM (Resistance, Ω)
Range Res. Accuracy
110Ω 0.01Ω ±(1% of reading +5 digits)
1kΩ 0.0001kΩ ±(1% of reading +2 digits)
11kΩ 0.001kΩ 250VDC or AC RMS
110kΩ 0.01kΩ
1MΩ 0.0001MΩ ±(3% of reading +5 digits)
11MΩ 0.001MΩ ±(3% of reading +10 digits)
110MΩ 0.1MΩ ±(3% of reading +10 digits)
Overload Protection:
Frequency (Hz)
Range Res. Accuracy
1100.0Hz 0.1Hz
11.000kHz 0.001kHz
110.00MHz 0.01kHz
1.1000MHz 0.0001MHz 250VDC or AC RMS
11.000MHz 0.001MHz
110.00MHz 0.01MHz
Warning: Use only correct type and overvoltage
±(1% of reading +2 digits)
Overload Protection:
category rated test leads. Remove the
temperature probe when using the test
leads or amp clamp.
9
Diode Test
Test Current Over Load Protection
1.5mA MAX 250 V DC or AC RMS
Continuity Buzzer
Test Voltage Threshold Over Load Protection
3V <35Ω 250 V DC or AC RMS
Non-Contact Voltage (NCV)
Detection Range: 24VAC and above
Temperature (K-Type thermocouple)
Range Res. Accuracy
-30ºF to 1000ºF 1ºF +
(2ºF) 32.0ºF to 120ºF
+ (1%+2ºF) -3ºF to 749ºF
+
(2%+1.5ºF) 750ºF to 1000ºF
+ (2%+4ºF) -40ºF to -4ºF
Overload Protection: 60VDC or 30VAC RMS
**Celsius version of the 275 is available
10
Warning: Use only correct type and overvoltage
category rated test leads. Remove the
temperature probe when using the test
leads or amp clamp.
11
Capacitance
Range Res. Accuracy
11nF 0.001nF
±(3% of reading +5 digits)
110nF 0.01nF
1.1uF 0.0001uF Overload Protection:
11µF 0.001µF 500VDC or AC RMS
110µF 0.01µF
1.1mF 0.0001mF
11mF 0.001mF
110mF 0.01mF
±(7% of reading +5 digits)
nF= nanofarad, µF= microfarad, mF= millifarad
General
Max Voltage between any 600V
input and ground
Fuse Protection (µµA range) 0.5A/600V
Display Type 4000 Count 41 seg. bargraph
Operating Temperature 32ºF to 104ºF (0ºC to 40ºC)
Storage Temperature 14ºF to 122ºF (-10ºC to 50ºC)
Relative Humidity 80% non-condensing
Power Supply 9V (MN1604)
Battery Life 80 hrs. typical
Size (H x L x W) 32.5mm x 255mm x 65mm
(1.3in x 10in x 2.5in)
Weight 363g (0.8lbs)
Warning: Use only correct type and overvoltage
category rated test leads. Remove the
temperature probe when using the test
leads or amp clamp.
12
D. MEASUREMENT TECHNIQUES
1. Controls and Functions:
Push Buttons
REL Activates Relative mode. Press
and hold for 2 seconds to deactivate.
D-H Holds the reading on the display
until the button is pushed a
second time.
R-H Activates manual ranging. Press
and hold for 2 seconds to return
to auto ranging.
MAX MIN Activates record mode. Press to
cycle between maximum and minimum recorded reading. Press and
hold for 2 seconds to return to
normal mode.
P-H Activates peak hold mode. Used to
capture in-rush current.
NCV Activates the non-contact voltage
detection feature. Press and hold
while holding the jaw close to
electrical wires.
13
1. Controls and Functions: (cont.)
Rotary Switch
OFF Turns the 275 completely off.
V Used to measure DC volts.
V Used to measure AC volts.
ΩΩ
Used to measure resistance.
Used to measure continuity.
Selects diode test function.
Selects capacitance test function.
Hz Selects frequency test function.
µµ
A Selects DC microamp function.
Used to measure AC amperage.
TEMP Selects the temperature function.
Input Jacks
COM Black test lead connection for all
tests except temperature, non-contact voltage and AC Amps.
V/ΩΩ/µµA Red test lead connection for all
tests except temperature, non-contact voltage and AC Amps.
Measuring AC Voltage
Instrument set-up:
FUNC. BLACK RED MIN MAX
Measurement Procedure:
1. Disconnect power to circuit to be measured.
2. Plug black test lead into the COM input jack.
3 Plug red test lead into the V/Ω input jack.
4. Set rotary switch to the V range.
5. Connect test leads to circuit to be measured.
6. Reconnect power to circuit to be measured.
7. Read the voltage on the 275.
Optional Modes
• D-H: Freezes the reading on the LCD.
• MAX/MIN: Records minimum and maximum measurements.
• P-H: Displays peak voltage.
2. Step by Step Procedures:
Measuring DC V
oltage
WARNING!
Do not attempt to make a voltage measurement of more
than 600V or of a voltage level that is unknown. Make sure
the temperature probe is NOT
plugged in during this test.
Instrument set-up:
FUNC. BLACK RED MIN MAXI
TEST LEAD TEST LEAD READING READING
COM V/Ω 0.1mV 600V
Measurement Procedure:
1. Disconnect power to circuit to be measured.
2. Plug black test lead into the COM input jack.
3 Plug red test lead into the V/Ω input jack.
4. Set rotary switch to the V range.
5. Connect test leads to circuit to be measured.
6. Reconnect power to circuit to be measured.
7. Read the voltage on the 275.
Optional Modes
(See Other Features Section)
• D-H: Freezes the reading on the LCD.
• MAX/MIN: Records minimum a.
• P-H: Displays peak voltage.
14
Measuring AC Voltage
WARNING!
Do not attempt to make a voltage measurement of more than
600V or of a voltage level that is unknown. Make sure the temperature probe is NOT plugged in during this test.
Instrument set-up:
FUNC. BLACK RED MIN MAX
TEST LEAD TEST LEAD READING READING
COM V/Ω 0.1mV 600V
Measurement Procedure:
1. Disconnect power to circuit to be measured.
2. Plug black test lead into the COM input jack.
3 Plug red test lead into the V/Ω input jack.
4. Set rotary switch to the V range.
5. Connect test leads to circuit to be measured.
6. Reconnect power to circuit to be measured.
7. Read the voltage on the 275.
Optional Modes
(See Other Features Section)
• D-H: Freezes the reading on the LCD.
• MAX/MIN: Records minimum and maximum measurements.
• P-H: Displays peak voltage.
15
Measuring AC Amperage
Instrument set-up:
FUNC. BLACK RED MIN MAX
Measurement Procedure:
1. Disconnect power to circuit to be measured.
2. Set rotary switch to function.
3. Clamp the jaws around one conductor of the circuit to
4. Reconnect power to circuit to be measured.
5. Read the current on the 275.
Optional Modes
• D-H: Freezes the reading on the LCD.
•
• P-H: Displays peak amperage.
16
Measuring Resistance
WARNING!
Do not attempt to make resistance measurements with circuit
energized. For best results, remove the resistor completely from
circuit before attempting to measure it. Make sure the temperature probe is NOT plugged in during this test.
NOTE:
To make accurate low ohm measurements, short the ends of the
test leads together and press the REL button to store the reading.
This will deduct the stored value from subsequent measurements
eliminating the test lead resistance from the reading.
Instrument set-up:
FUNC. BLACK RED MIN MAX
TEST LEAD TEST LEAD READING READING
Ω COM V/Ω 0.1Ω 40.00MΩ
Measurement Procedure:
1. Disconnect power to circuit to be measured.
2. Plug black test lead into the COM input jack.
3. Plug red test lead into V/Ω input jack.
4. Set the rotary switch to the Ω function.
5. Connect test leads to circuit to be measured.
6. Read the resistance value on the 275.
Optional Modes
(See Other Features Section)
• D-H: Freezes the reading on the LCD.
Measuring AC Amperage
CAUTION!
Do not attempt to make a current measurement with the
test leads. The 275 measures the current by clamping the
jaw around one conductor (wire). Clamping around more
than one wire will result in erroneous readings. Make sure
the temperature probe is NOT plugged in during this test.
Instrument set-up:
FUNC. BLACK RED MIN MAX
TEST LEAD TEST LEAD READING READING
NOT USED NOT USED 0.01A 400A
Measurement Procedure:
1. Disconnect power to circuit to be measured.
2. Set rotary switch to function.
3. Clamp the jaws around one conductor of the circuit to
be measured. For best results, center the wire in the
jaw.
4. Reconnect power to circuit to be measured.
5. Read the current on the 275.
Optional Modes
(See Other Features Section)
• D-H: Freezes the reading on the LCD.
•
MAX/MIN: Records minimum and maximum measure-
ments
• P-H: Displays peak amperage.
17
18
Measuring Continuity
Measurement Procedure:
1. Disconnect power to circuit to be measured.
2. Plug black test lead into the COM input jack.
3. Plug red test lead into V/Ω input jack.
4. Set the rotary switch to the position.
5. Connect test leads to circuit to be measured.
6. The 275 will beep and the LED will illuminate at
Optional Modes
• D-H: Freezes the reading on the LCD.
Measuring DC Amperage
CAUTION!
Do not attempt to make a current measurement with the
test leads. The 275 measures the current by clamping the
jaw around one conductor (wire). Clamping around more
than one wire will result in erroneous readings. Make sure
the temperature probe is NOT plugged in during this test.
Instrument set-up:
FUNC. BLACK RED MIN MAX
TEST LEAD TEST LEAD READING READING
NOT USED NOT USED 0.01A 400A
Measurement Procedure:
1. Disconnect power to circuit to be measured.
2. Set rotary switch to function.
3. Clamp the jaws around one conductor of the circuit to
be measured. For best results, center the wire in the
jaw.
4. Reconnect power to circuit to be measured.
5. Read the current on the 275.
Optional Modes
(See Other Features Section)
• D-H: Freezes the reading on the LCD.
• MAX/MIN: Records minimum and maximum measurements
• P-H: Displays peak amperage.
19
Measuring Continuity
WARNING!
Do not attempt to make continuity measurements with circuit
energized. Make sure the temperature probe is NOT
plugged
in during this test.
Instrument set-up:
FUNC. BLACK RED
TEST LEAD TEST LEAD
COM V/Ω
Measurement Procedure:
1. Disconnect power to circuit to be measured.
2. Plug black test lead into the COM input jack.
3. Plug red test lead into V/Ω input jack.
4. Set the rotary switch to the position.
5. Connect test leads to circuit to be measured.
6. The 275 will beep and the LED will illuminate at
resistances of 35Ω or lower.
Optional Modes
(See Other Features Section)
• D-H: Freezes the reading on the LCD.
Measuring Capacitance
Measurement Procedure:
1. Disconnect power to circuit to be measured.
2. Plug black test lead into the COM input jack.
3. Plug red test lead into V/Ω input jack.
4. Set the rotary switch to the
5. Remove the capacitor from the circuit and discharge it.
6. Connect test leads to the capacitor to be measured.
7. Read the capacitor value on the LCD.
Optional Modes
• D-H: Freezes the reading on the LCD.
Measuring Diodes
WARNING!
Do not attempt to make diode measurements with the circuit
energized. For accurate tests, remove the diode completely
from the circuit prior to measuring it. Make sure the temperature probe is NOT plugged in during this test.
Instrument set-up:
FUNC. BLACK RED
TEST LEAD TEST LEAD
COM V/Ω/µA
Measurement Procedure:
1. Disconnect power to circuit to be measured.
2. Plug black test lead into the COM input jack.
3. Plug red test lead into V/Ω input jack.
4. Set the rotary switch to the
5. Connect the black test lead to the banded end of the diode
(cathode) and the red test lead to the non-banded end of
the diode (anode).
6. For a good diode, the reading on the display should be
between 0.5V and 0.8V. The reading will be lower for a
germanium diode.
7. Reverse the leads on the diode.
8. For a good diode, the reading on the display should be OL
(overload).
Optional Modes
(See Other Features Section)
• D-H: Freezes the reading on the LCD.
position.
Measuring Capacitance
WARNING!
All capacitance measurements are to be made on de-energized
circuits with all capacitors discharged only. Failure to de-energize
and discharge capacitors prior to measuring them could result in
instrument damage and/or personal injury. Make sure the temperature probe is NOT
plugged in during this test.
Instrument set-up:
FUNC. BLACK RED
TEST LEAD TEST LEAD
COM V/Ω/µA
Measurement Procedure:
1. Disconnect power to circuit to be measured.
2. Plug black test lead into the COM input jack.
3. Plug red test lead into V/Ω input jack.
4. Set the rotary switch to the
5. Remove the capacitor from the circuit and discharge it.
6. Connect test leads to the capacitor to be measured.
Observe polarity on polarity sensitive capacitors.
7. Read the capacitor value on the LCD.
Optional Modes
(See Other Features Section)
• D-H: Freezes the reading on the LCD.
21
position.
Measuring DC Microamps
Instrument set-up:
FUNC. BLACK RED MINIMUM MAXIMUM
Measurement Procedure:
Optional Modes
• D-H: Freezes the reading on the LCD.
• MAX/MIN: Records minimum and maximum measure-
22
Measuring Frequency
WARNING!
Never attempt a frequency measurement with a voltage source
greater than 500V. Determine the voltage of any unknown frequency source before connecting the instrument in frequency
mode. Make sure the temperature probe is NOT plugged in
during this test.
Instrument set-up:
FUNC. BLACK RED
TEST LEAD TEST LEAD
Hz COM V/Ω/µA
Measurement Procedure:
1. Disconnect power to the circuit to be measured.
2. Plug black test lead into the COM input jack.
3. Plug red test lead into V/Ω input jack.
4. Set the rotary switch to the Hz position.
5. Reconnect power to the circuit to be measured.
6. Read the frequency on the LCD.
Optional Modes
(See Other Features Section)
• D-H: Freezes the reading on the LCD.
• MAX/MIN: Records minimum and maximum measurements
Measuring DC Microamps
CAUTION!
Do not attempt to make a current measurement with the test
leads connected in parallel with the circuit to be tested. Test
leads must be connected in series with the circuit. Do not
attempt to make a current measurement of circuits with more
than 600V present. Instrument damage and/or personal injury
may result. Make sure the temperature probe is NOT
plugged
in during this test.
Instrument set-up:
FUNC. BLACK RED MINIMUM MAXIMUM
TEST LEAD TEST LEAD READING READING
COM V/Ω /µA 0.01µA 400.0µA
Measurement Procedure:
1. Disconnect power to circuit to be measured.
2. Plug black test lead into the COM input jack.
3. Plug red test lead into the V/
ΩΩ/µµ
A input jack.
4. Set the rotary switch to the
µµ
A function.
5. Connect the test leads in series to the circuit to be
measured.
6. Reconnect power to circuit to be measured.
7. Read the current on the 275.
Optional Modes
(See Other Features Section)
• D-H: Freezes the reading on the LCD.
• MAX/MIN: Records minimum and maximum measurements.
23
E. Other Features
Non-Contact V
Measurement Procedure:
Remove the test leads and temperature probe prior to using the
NCV feature.
1. Turn the meter on to any range.
2. Press and hold the NCV button.
3. Put the arrow marked on the jaw close to the wire under
4. If voltage is present the 275 will beep and the NCV LED
5. If voltage is not detected, confirm the result by perform-
Measuring Temperature
CAUTION!
Do not attempt to make a temperature measurement with the
test leads connected to the 275. Remove the test leads and
insert the K-type temperature probe.
Instrument set-up:
FUNC. BLACK RED MINIMUM MAXIMUM
TEST LEAD TEST LEAD READING READING
400ºF N/A N/A -40.0ºF 399.9ºF
1000ºF N/A N/A -40ºF 1000ºF
Measurement Procedure:
1. Remove the test leads from the input jacks.
2. Observing polarity, insert the temperature probe
into the Type K input jack.
3. Set the rotary switch to the appropriate function
for the temperature being measured.
4. Touch the temperature probe to the item to be
measured.
5 . Read the temperature on the LCD.
Note:The 275 will beep when no probe is connected to
the temperature input.
Optional Modes
(See Other Features Section)
• D-H: Freezes the reading on the LCD.
• MAX/MIN: Records minimum and maximum measure
ments.
• REL: Enables temperature differential tests to be per
formed. See Application Notes section.
25
E. Other Features
Non-Contact V
oltage (NCV)
WARNING!
Never rely on the non-contact voltage function only. If a voltage is not detected, confirm there is no voltage by performing
a voltage measurement with the test leads. Failure to do this
could result in injury. The non-contact voltage feature works
best when testing single wires. Make sure the test leads and
temperature probe are disconnected while using the NCV feature.
Instrument set-up:
FUNC. BLACK RED
TEST LEAD TEST LEAD
NCV N/A N/A
Measurement Procedure:
Remove the test leads and temperature probe prior to using the
NCV feature.
1. Turn the meter on to any range.
2. Press and hold the NCV button.
3. Put the arrow marked on the jaw close to the wire under
test.
4. If voltage is present the 275 will beep and the NCV LED
will illuminate.
5. If voltage is not detected, confirm the result by performing a voltage measurement as outlined earlier in this
manual.
26
Other Features (continued)
Record Mode (MAX / MIN)
Other Features (continued)
Relative mode (REL)
The Relative mode (REL) takes the reading on the display at the time the REL button is pressed and uses it as
a reference value that is deducted from all subsequent
measurements. This can be very helpful in deducting the
resistance of test leads in low ohm measurements.
1. To use Relative mode manually select the range
for the function.
2. Depress the REL button to store the reading on the
display. The “REL” indicator will illuminate confirming the 275 is in relative mode.
3. Now when making a measurement the value
stored will be deducted from the actual reading.
4. To see what the stored value is, depress the REL
button again and the “REL” indicator will flash and
the reading on the display will show the stored
value. Depress the REL button again to return to
REL mode.
5. To clear or exit relative mode, press and hold the
REL button for approximately two seconds and the
275 will beep and return to normal operation.
Note: Differential temperature measurements can be
made using relative mode. See the application note
on page 33 for more information.
27
Other Features (continued)
Record Mode (MAX / MIN)
Record mode allows you to record the maximum and
minimum readings measured during a test.
1. Manually select the range for the function and set
the meter up to perform a measurement as outlined
earlier in this manual.
2. Depress the MAX/MIN button and “MAX” will be
displayed along with the maximum reading recorded. Press the MAX/MIN button again and the display
will show MIN and the minimum reading recorded.
3. Press the MAX/MIN button again and MAX MIN will
blink and the 275 will display the measured value in
real time. Steps 2 and 3 can be repeated to read the
maximum and minimum recorded values.
If REL was activated and is being used with
MAX/MIN, REL and MAX MIN will blink and the display will show the REL value instead of the real time
reading.
5. To exit record mode, press and hold the MAX/MIN
button for approximately two seconds and the 275
will beep and return to normal operation.
28
Other Features (continued)
Manual Ranging (R-H)
The range hold button (R-H) activates manual ranging.
Press the R-H button to cycle through available ranges.
Pressing and holding the R-H button for approximately two
seconds returns the meter to autorange mode and “auto” will
be displayed in the upper left corner of the display.
Data Hold (D-H)
Press the D-H button at any time to freeze the reading on the
LCD display. This function is useful when measuring in
locations where the display is difficult to read.
LED Indicators
The 275 is equipped with three LED indicators at the top near
the jaw.
HI-V This indicator flashes and the 275 beeps
when the test leads are in contact with a
NCV This indicator illuminates when the non-
Other Features (continued)
Peak Hold Mode (P-H)
The Peak hold function allows the 275 to display the the
maximum and minimum peak voltage or current. This is
helpful when measuring inrush current.
NOTE: Peak mode can display up to 70 counts on the display when first activated. For example, if the 275 is set to
the ACA function and manually ranged to the 40A range,
when P-H is activated the display can read up to 0.70.
This is normal for this function.
1. Manually select the range for the function and set
the meter up to perform a measurement as outlined
earlier in this manual.
2. Depress and hold the P-H button until CAL is displayed. Once CAL clears from the display you may
make a measurement. Press P-H repeatedly to cycle
through the maximum and minimum peak readings.
Press and hold the P-H button for two seconds to
return to normal operation.
For inrush current, after CAL clears press the P-H
button and then supply power to the device under
test. The 275 will capture the maximum and minimum peak inrush.
29
Other Features (continued)
Manual Ranging (R-H)
The range hold button (R-H) activates manual ranging.
Press the R-H button to cycle through available ranges.
Pressing and holding the R-H button for approximately two
seconds returns the meter to autorange mode and “auto” will
be displayed in the upper left corner of the display.
Data Hold (D-H)
Press the D-H button at any time to freeze the reading on the
LCD display. This function is useful when measuring in
locations where the display is difficult to read.
LED Indicators
The 275 is equipped with three LED indicators at the top near
the jaw.
HI-V This indicator flashes and the 275 beeps
when the test leads are in contact with a
voltage of 30V AC/DC or more.
NCV This indicator illuminates when the non-
contact voltage detector senses a voltage.
This is the visual indicator of continuity. This
LED also flashes anytime the buzzer beeps.
30
Application Notes (DC Volts)
The 275 will accurately measure rectified DC Voltages like
those encountered in furnaces and other appliances even
though many of these devices do not have output filtering
or other signal conditioning.
F. Application Notes (AC Volts)
Disconnect power from the
terminal block, find the fuse
or circuit breaker that controls the block and turn it
off.
Set up the meter following
the steps under
“Measurement Procedure”
on page 15. Then proceed with
the following:
•Connect the red test lead to
the hot side of the block and
the black lead to the neutral
side of the block. Reconnect
power to the block and read
the voltage on the meter. The
reading should be approximately 110V to
130V.
• Disconnect power from the block and move
the red wire to ground. Reconnect power to
the block and read the voltage on the meter.
Typically less than 20V should exist from
neutral to ground. If 110V or above exists,
the block may be wired incorrectly.
31
Application Notes (DC Volts)
The 275 will accurately measure rectified DC Voltages like
those encountered in furnaces and other appliances even
though many of these devices do not have output filtering
or other signal conditioning.
When measuring DC Voltage of a battery, the most accurate reading can be
attained by testing the battery under
load. To accomplish this, follow steps
1 through 4 shown on page 14 and
the following (with the battery in
holder and device turned on):
• Connect the red test lead from the
meter to the positive (+) terminal
of the battery.
• Connect the black test lead to the
negative (-) terminal of the battery.
32
When measuring resistance of a motor, make
sure the power is disconnected prior to testing.
Set up meter following steps under
“Measurement Procedure” on page 16, and
proceed with the following:
• Connect the red test lead to one power
input line of the motor and the black test
lead to the other power input line of the
motor. In most applications if the reading
is OFL, the motor winding is open.
• Connect the red test lead to the frame of
the motor and the black test lead to the
winding. In most applications if a reading
of 0 Ohms is displayed, the winding is
shorted to the motor frame (ground).
Application Notes (Resistance)
33
Application Notes (AC Amps)
When measuring AC Amps of a motor there
are two types of measurements that can be
made, running current and in-rush or start-up
current. Start-up current will usually be much
higher than running current.
Set up the meter following the steps under
“Measurement Procedure” on page 17, and
then proceed with the following:
• Clamp the meter around a single wire
and reconnect power to the device. Read
the current displayed on the meter. This
is the running current of the motor.
• Disconnect power to the motor and put
the meter in PEAK HOLD mode.
Reconnect the power and read
the current displayed on the
meter. This is the in-rush or
start-up current
of the motor.
34
G. Trouble Shooting
Problem Probable Causes
Does not power up
Won’t display DC
microamp readings
All functions except
ohms read high
AC Volts do not read
Non-Contact Voltage
does not work
The meter beeps when
set on TEMP
AC Amps does not read
Application Notes (Temperature Differential)
When measuring temperature there may be applications when knowing the differential between two measurements is required. This can be accompished by
following these steps.
• Remove the test leads from the input jacks. Insert
the K-type thermocouple probe into the input jack
on the 275. Set the 275 to the desired TEMP
function.
• Touch the temperature probe sensor to the device
under test (T1).
• When the reading stabilizes, press the REL button. The display will read “0” and T1 will be
stored as the reference value that the next measurement will be made relative to.
• Touch the temperature probe sensor to the device
under test (T2).
• The 275 will display the differential temperature
T2-T1.
35
G. Trouble Shooting
Problem Probable Causes
Does not power up
• Dead or defective battery
• Broken wire from battery
snap to PCB
Won’t display DC
• Open fuse
microamp readings
• Open test lead
• Improperly connected to
circuit under test
All functions except
• Very weak battery that will
ohms read high
not turn on the low battery
indicator on the LCD
AC Volts do not read
• Very weak battery that will
not turn on the low battery
indicator on the LCD
Non-Contact Voltage
• The non-contact voltage feature
does not work
works best when used to test a
single wire. Make sure the arrow
on the jaw is pointed at the wire.
The meter beeps when
• This is a reminder to remove the
set on TEMP
test leads and insert the temperature probe. If a probe is inserted, this is an indication the probe
is open.
AC Amps does not read
• Make sure the jaw is clamped
around a single wire and the
device connected to the wire is
turned on.
36
Accessories
Standard Accessories
9 Volt Alkaline Battery A009A
Test Lead Set (1000V CATIII 10A) A085
0.5A / 600V Fuse A107
Soft Carrying Pouch A275
Optional Accessories
Fused Test Lead Kit FTLK3
Deluxe Test Lead Set TLS2000RB
Carbon Monoxide Adapter A771
Pressure Adapter A620
H. Maintenance
1. Battery / Fuse Replacement: The 275 will display a bat-
tery symbol when the internal 9 Volt battery needs
replacement. If DC microamps does not operate correctly the 0.5A / 600V fuse needs to be replaced. The battery
or fuse is replaced as follows:
a. Disconnect and remove all test leads
from live circuits and from the 275.
b. Loosen the screw from the back of the 275 battery /
fuse cover.
c. Remove the battery / fuse compartment cover.
d. Remove old battery or fuse and replace with new
battery or fuse. Observe the correct polarity on the
battery. Only install the correct value fuse
(0.5A/600V). Failure to do so can result in instru-
ment damage.
e. Reassemble the instrument in reverse
order from above.
2. Cleaning your 275:
Use a mild detergent and slightly damp cloth to clean the
surfaces of the 275.
37
Accessories
Standard Accessories
Part Number
9 Volt Alkaline Battery A009A
Test Lead Set (1000V CATIII 10A) A085
0.5A / 600V Fuse A107
Soft Carrying Pouch A275
Optional Accessories
Part Number
Fused Test Lead Kit FTLK3
Deluxe Test Lead Set TLS2000RB
Carbon Monoxide Adapter A771
Pressure Adapter A620
38
39
Func. Range
Res.
DCV 1100mV 0.01mV
1V 0.0001V
11V 0.001V
110V 0.01V
600V 0.1V
ACV 110mV 0.01mV
1V 0.0001V
11V 0.001V
100V 0.01V
600V 0.1V
ACA/DCA 110A 0.01A
400A 0.1A
OHM 110Ω 0.01Ω
1.1kΩ 0.0001kΩ
11kΩ 0.001kΩ
110kΩ 0.01kΩ
1.1MΩ 0.0001MΩ
11MΩ 0.001MΩ
111MΩ 0.01MΩ
DCuA 110uA 0.01uA
1100uA 0.1uA
TEMP -30ºF to 1000ºF 0.1ºF
275 SPECIFICATIONS (PARTIAL LIST)
±0.5% Basic DCV Accuracy (also see pages 8-11)
Test Products International, Inc.
9615 SW Allen Blvd., Ste. 104
Beaverton, OR USA 97005
503-520-9197 • Fax: 503-520-1225
info@tpi-thevalueleader.com
L275M • 1/25/05 copyright © 2005 Test Products International, Inc.
Loading...