Tenmars TM-87 User manual

Autoranging True RMS Multimeter
TM-87 / TM-88
User’s manual
HB2TM8700000

TM-87/TM-88
Contents:
1. SAFETY PRECAUTIONS AND PROCEDURES..........................................................2
1.1. Preliminary ............................................................................................................2
1.2. During use.............................................................................................................3
1.3. After use................................................................................................................3
1.4. Measuring (overvoltage) categories definitions .....................................................3
2. GENERAL DESCRIPTION...........................................................................................4
2.1. Mean value and TRMS: definition..........................................................................4
2.2. True root mean square value and crest factor: definition.......................................4
3. PREPARATION FOR USE...........................................................................................5
3.1. Initial......................................................................................................................5
3.2. Supply voltage.......................................................................................................5
3.3. Calibration .............................................................................................................5
3.4. Storage..................................................................................................................5
4. OPERATING INSTRUCTIONS.....................................................................................6
4.1. Instrument - description.........................................................................................6
4.1.1. Front panel................................................................................................................... 6
4.2. Description of function keys...................................................................................7
4.2.1. HOLD key..................................................................................................................... 7
4.2.2. PK/REL key.................................................................................................................. 7
4.2.3. MX/MN key................................................................................................................... 7
4.2.4. R/SEL key.................................................................................................................... 7
4.2.5. Backlight key ( )...................................................................................................... 8
4.2.6. Disable Auto Power OFF ............................................................................................. 8
4.3. Measurements.......................................................................................................9
4.3.1. DC Voltage measurement............................................................................................ 9
4.3.2. AC Voltage measurement.......................................................................................... 10
4.3.3. DC Current measurement.......................................................................................... 11
4.3.4. AC Current measurement.......................................................................................... 12
4.3.5. Resistance measurement and Continuity Test .......................................................... 13
4.3.6. Diode test................................................................................................................... 14
4.3.7. Capacitance measurement........................................................................................ 15
4.3.8. Frequency measurement........................................................................................... 16
4.3.9. Temperature test (Only for TM-88) ............................................................................ 17
5. MAINTENANCE .........................................................................................................18
5.1. General information.............................................................................................18
5.2. Battery replacement ............................................................................................18
5.3. Fuse replacement................................................................................................19
5.4. Cleaning ..............................................................................................................19
5.5. End of life ............................................................................................................19
6. TECHNICAL SPECIFICATIONS ................................................................................20
6.1. Technical features...............................................................................................20
6.1.1. Electrical specifications.............................................................................................. 22
6.1.2. Safety......................................................................................................................... 22
6.1.3. General data .............................................................................................................. 23
6.2. Environment ........................................................................................................23
6.2.1. Environmental conditions........................................................................................... 23
6.2.2. EMC and LVD............................................................................................................ 23
6.3. Accessories.........................................................................................................23
6.3.1. Standard accessories................................................................................................. 23
7. SERVICE....................................................................................................................24
7.1. Warranty conditions.............................................................................................24
7.2. After-sale service.................................................................................................24
1

TM-87/TM-88
1. SAFETY PRECAUTIONS AND PROCEDURES
This meter is in compliance with safety Standards EN 61010-1 related to electronic
measuring instruments. For your own safety and to avoid damaging the instrument follow
the procedures described in this instruction manual and read carefully all notes preceded
by this symbol .When taking measurements:
• Avoid doing that in humid or wet places - make sure that humidity is within the limits
indicated in paragraph 6.2.1.
• Avoid doing that in rooms where explosive gas, combustible gas, steam or excessive
dust is present.
• Keep you insulated from the object under test.
• Do not touch exposed metal parts such as test lead ends, sockets, fixing objects,
circuits etc.
• Avoid doing that if you notice anomalous conditions such as breakages, deformations,
fractures, leakages of battery liquid, blind display etc.
• Be particularly careful when measuring voltages exceeding 20V to avoid risk of
electrical shocks.
The following symbols are used:
CAUTION - refer to the instruction manual - an improper use may damage the
instrument or its components
Danger high voltage: risk of electric shocks
Double insulated meter
AC voltage or current
DC voltage or current
1.1. PRELIMINARY
• This instrument has been designed for use in environments of pollution degree 2.
• It can be used for VOLTAGE and CURRENT measurements on installations of overvoltage
CAT III 1000V and CAT IV 600V.
• This instrument is not suitable for measurements of non sine wave voltage and current.
• When using the instrument always respect the usual safety regulations aimed at
protecting you against the dangerous electric currents and protecting the instrument
against incorrect operations.
• Only the leads supplied with the instrument guarantee compliance with the safety
standards in force. They must be in good conditions and, if necessary, replaced with
identical ones.
• Do not test or connect to any circuit exceeding the specified overload protection.
• Do not effect measurements under environmental conditions exceeding the limits
indicated in paragraphs 6.1.1 and 6.2.1.
• Make sure that batteries are properly installed.
• Before connecting the test probes to the installation make sure that the rotary selector
is positioned on the right function.
• Make sure that LCD and rotary selector indicate the same function.
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TM-87/TM-88
1.2. DURING USE
CAUTION
An improper use may damage the instrument and/or its components or
injure the operator.
• When changing the range, first disconnect the test leads from the circuit under test in
order to avoid any accident.
• When the instrument is connected to measuring circuits never touch any unused
terminal.
• When measuring resistors do not add any voltage. Although there is a protection
circuit, excessive voltage could cause malfunctioning.
• If during measurement the displayed values remain constant check whether the HOLD
function is active.
1.3. AFTER USE
• After using the instrument turn it off.
• If you expect not to use the instrument for a long period remove the battery to avoid
leakages of battery liquids which may damage its inner components.
1.4. MEASURING (OVERVOLTAGE) CATEGORIES DEFINITIONS
EN 61010-1: Safety requirements for electrical equipment for measurement, control and
laboratory use, Part 1: General requirements, gives a definition of measuring category,
usually called overvoltage category. Paragraph 6.7.4: Measuring circuits:
(OMISSIS)
circuits are divided into the following measurement categories:
• Measurement category IV is for measurements performed at the source of the
low-voltage installation.
Examples are electricity meters and measurements on primary overcurrent
protection devices and ripple control units.
• Measurement category III is for measurements performed in the building
installation.
Examples are measurements on distribution boards, circuit breakers, wiring,
including cables, bus-bars, junction boxes, switches, socket-outlets in the fixed
installation, and equipment for industrial use and some other equipment, for
example, stationary motors with permanent connection to fixed installation.
• Measurement category II is for measurements performed on circuits directly
connected to the low voltage installation..
Examples are measurements on household appliances, portable tools and similar
equipment..
• Measurement category I is for measurements performed on circuits not directly
connected to MAINS.
Examples are measurements on circuits not derived from MAINS, and specially
protected (internal) MAINS-derived circuits. In the latter case, transient stresses are
variable; for that reason, the norm requires that the transient withstand capability of
the equipment is made known to the user.
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TM-87/TM-88
2. GENERAL DESCRIPTION
This meter performs the below listed measurements:
• DC and AC TRMS Voltage
• DC and AC TRMS Current
• Resistance and Continuity test
• Frequency
• Capacitance
• Diode test
All selectable by means of a 10 position rotary selector (including OFF position). Functions
keys are also available (see chapter 4.2). An analogical bargraph is also available. The
selected quantity is displayed with indication of measuring unit and active functions.
The instrument disposes of an Auto Power Off function consisting in an automatic
switching off 30 minutes after last selector rotation or function selection.
2.1. MEAN VALUE AND TRMS: DEFINITION
Safety testers for AC quantities are divided in two big families:
• MEAN VALUE instruments, measuring only the value of the wave at the
fundamental frequency (50 or 60 Hz)
• TRUE ROOT MEAN SQUARE (or “TRMS”) instruments, measuring the true root
mean square value of the quantity under test.
In presence of a perfectly sinusoidal wave, both families provide identical results. While in
presence of distorted waves, readings are different. Mean value instruments provide only
the value of the fundamental wave while TRMS instruments provide the value of the entire
wave, including harmonics (within the passband of the instrument). Accordingly, if the
same quantity is measured with both kinds of instruments, the measured values are
identical only if the wave is purely sinusoidal. Should it be distorted, TRMS instruments
provide higher values than MEAN VALUE instruments.
2.2. TRUE ROOT MEAN SQUARE VALUE AND CREST FACTOR: DEFINITION
The effective current value is defined as follows: “In an interval of time equivalent to a
period, an alternate current with effective value having an intensity of 1A, by passing on a
resistor, disperses the same energy which would be dispersed in the same period of time
by a direct current having an intensity of 1A”. From this definition comes the numerical
expression: G= ∫
+Tt
t
dttg
T
0
0
)(
12The effective value is indicated as RMS (root mean square).
The Crest Factor is defined as the ratio between the Peak Value of a signal and its
effective value: CF (G)= RMS
p
G
G. This value varies according to the waveform of the signal,
for a purely sinusoidal wave it’s worth 2=1.41. In presence of distortions the Crest Factor
assumes higher values as long as the wave distortion is higher.
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TM-87/TM-88
3. PREPARATION FOR USE
3.1. INITIAL
This instrument was checked both mechanically and electrically prior to shipment. All
possible cares and precautions were taken to let you receive the instrument in perfect
conditions. Notwithstanding we suggest you to check it rapidly (eventual damages may
have occurred during transport – if so please contact the local distributor from whom you
bought the item).
Make sure that all standard accessories mentioned in paragraph 6.3.1 are included.
Should you have to return back the instrument for any reason please follow the
instructions mentioned in paragraph 7.
3.2. SUPPLY VOLTAGE
The instrument is supplied by 1x9V battery type NEDA1604 JIS006P IEC6F22. When
battery is low, a low battery indication “ ” is displayed. To replace/insert battery please
refer to paragraph 5.2.
3.3. CALIBRATION
The instrument complies with the technical specifications contained in this manual and such
compliance is guaranteed for 1 year. Annual recalibration is recommended.
3.4. STORAGE
After a period of storage under extreme environmental conditions exceeding the limits
mentioned in paragraph 6.2.1 let the instrument resume normal measuring conditions
before using it.
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TM-87/TM-88
4. OPERATING INSTRUCTIONS
4.1. INSTRUMENT - DESCRIPTION
4.1.1. Front panel
LEGEND:
1. LCD
2. HOLD Key
3. PK/ REL Key
4. MX/ MN Key
5. R/SEL Key
6. Backlight Key
7. OFF position
8. DCV position
9. ACV position
10. Posizione Ω/
11. position
12. position
13. Hz position
14. µADC position
℃and ℉position(TM-88)
15. µAAC position
DCµAandACµAposition(TM-88)
16. DCAandACAposition
17. COM,A,and VΩHz µA
℃℉
Fig. 1: Instrument description
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TM-87/TM-88
4.2. DESCRIPTION OF FUNCTION KEYS
When pressing a key, the corresponding symbol is displayed with a beep. To resume
default state turn the selector on another function.
4.2.1. HOLD key
By pressing HOLD key the measured value is frozen on the display where the symbol
"HOLD" appears. Press again HOLD to disable this function and resume normal operation.
4.2.2. PK/REL key
This key have the double function of measuring max/min peak values (active for ∼Vand
∼µApositions of rotary selector) and performing relative measurements (REL) for V, A,
Hz,Ω/,, and µApositions of rotary selector.
This key have the double function of measuring max/min peak values (active for ∼Vand
∼µApositions of rotary selector) and performing relative measurements (REL) for V, Hz,
Ω/,, and ℃/℉positions of rotary selector.(TM-88)
Press cyclically PK/REL to measure and save peak values. “PMAX” and “PMIN” symbols on
the display correspond to Maximum Peak and Minimum Peak values respectively which
are continuously updated by the meter. By keeping pressed PK/REL key for at least 3
seconds, “CAL” symbol appears on the display and the meter performs an auto calibration
permitting a higher accuracy on peak measurements.
To exit this function keep pressed PK/REL for at least one second or rotate the selector on
another position.
By pressing PK/REL key, the relative measurement is activated: the meter saves the
(offset) value on the display and the “REL” symbol is shown. The following measurement
will be referred to this offset value. By pressing again PK/REL key the offset value is
shown and the “REL” symbol is blinking.
To exit this function keep pressed PK/REL for at least one second or rotate the selector on
another position.
4.2.3. MX/MN key
By pressing MX/MN key, maximum and minimum values are measured. Both values are
stored and automatically updated as soon as an higher value (MAX) or lower value (MIN)
are measured by meter. The symbol corresponding to the desired function is displayed:
“MAX” for maximum value, “MIN” for minimum value. MX/MN key is disabled when HOLD
function is active.
To exit this function keep MX/MN key pressed for at least 1 second or rotate the selector
to another position.
4.2.4. R/SEL key
By pressing R/SEL key the manual selection of measured range (exception , ∼Aand
Apositions) and the selection of a double function which are included on selector (by
choosing between Ωmeasure and AC or DC Current) are possible. The “MANU”
symbol is shown at display by pressing R/SEL key and the cyclically pressure of the key
change the measuring range and fix the decimal point on the display. Press R/SEL key at
least 1second or rotate the selector to exit from this function and restore the “AUTO”
symbol at display.
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TM-87/TM-88
4.2.5. Backlight key ( )
By pressing key it’s possible to activate the backlight function on the display. The
function automatically disabled itself after some seconds and is available on each position
of the rotary selector.
4.2.6. Disable Auto Power OFF
When the meter is to be used for long periods of time, the operator might want to disable
the AutoPowerOFF function. Once the AutoPowerOFF function is disabled the meter stays
on continuously. To disable the AutoPowerOFF function:
• Switch OFF the meter.
• Turn ON the meter keeping pressed PK/REL, MX/MIN and R/SEL keys.
The AutoPowerOFF function is automatically activated when turning ON again the meter.
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TM-87/TM-88
4.3. MEASUREMENTS
4.3.1. DC Voltage measurement
CAUTION
The maximum input for DC voltage is 1000V. Do not attempt to measure
higher voltages to avoid electrical shocks or damages to the instrument.
Fig. 2: Using the meter for DC Voltage measurement
1. Selecting the position V.
2. Pressing the R/SEL key to select the correct range or using the Autorange feature (see
paragraph 4.2.4). If the voltage value under test is unknown, select the highest range.
3. Insert the test leads into the jacks, the red plug into HzVΩµAjack and black plug
into COM jack (see Fig. 2).
4. Connect the red and black test leads to the positive and negative poles of the circuit
under test respectively. The voltage value is displayed.
5. If the message "O.L" is displayed select a higher range.
6. The symbol "-" on the instrument display indicates that voltage has opposite direction
with regard to the connection.
7. For HOLD function, Minimum and Maximum value measurement and Relative measure
please refer to paragraph 4.2.
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TM-87/TM-88
4.3.2. AC Voltage measurement
CAUTION
The maximum input for AC voltage is 750Vrms. Do not attempt to measure
higher voltages to avoid electrical shocks or damages to the instrument.
Fig. 3: Using the instrument for AC Voltage measurement
1. Selecting the position V.
2. Pressing the R/SEL key to select the correct range or using the Autorange feature (see
paragraph 4.2.4). If the voltage value under test is unknown, select the highest range.
3. Insert the test leads into the jacks, the red plug into HzVΩµAjack and black plug
into COM jack (see Fig. 3).
4. Connect the test leads to the circuit under test. The voltage value is displayed.
5. If the message "O.L" is displayed select a higher range.
6. For HOLD function, Minimum and Maximum value measurement and Peak
measurement please refer to paragraph 4.2.
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TM-87/TM-88
4.3.3. DC Current measurement
CAUTION
The maximum input for DC current is 10A. Do not attempt to measure
higher currents to avoid electrical shocks or damages to the instrument.
Fig. 4: Using the instrument for DC Current measurement
1. Power off the circuit under test.
2. Selecting the position . The message “ ” is shown at display.
3. Insert the test leads into the jacks, the red plug into Ajack and black plug into COM
jack (see Fig. 4).
4. Connect the red and the black plugs in series with the circuit whose current is to be
measured respecting the polarities.
5. Energize the circuit under test. The current value will be displayed.
6. The message "O.L." means that the detected current exceeds the limits.
7. If the measured value is lower than 4mA, to get a better resolution:
• Switch off the circuit under test.
• Turn the selector on µA.
• Remove the red test lead from Ajack, and insert it into HzVΩµAjack and power
the circuit under test. Press R/SEL key if necessary to select an higher range.
8. The symbol "-" on the instrument display indicates that current has opposite direction
with regard to the connection.
9. For HOLD function, Minimum and Maximum value measurement and Relative measure
please refer to paragraph 4.2.
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TM-87/TM-88
4.3.4. AC Current measurement
CAUTION
The maximum input for DC current is 10A. Do not attempt to measure
higher currents to avoid electrical shocks or damages to the instrument.
Fig. 5: Using the instrument for AC Current measurement
1. Power off the circuit under test.
2. Selecting the position A. By pressing R/SEL key to select AC measurement. The
“” symbol is shown at display.
3. Insert the test leads into the jacks, the red plug into Ajack and black plug into COM
jack (see Fig. 5).
4. Connect the red and the black plugs in series with the circuit whose current is to be
measured.
5. Energize the circuit under test. The current value will be displayed.
6. The message "O.L." means that the detected current exceeds the limits.
7. If the measured value is lower than 4mA, to get a better resolution:
• Switch off the circuit under test.
• Turn the selector on µA.
• Remove the red test lead from Ajack, and insert it into HzVΩµAjack and power
the circuit under test. Press R/SEL key if necessary to select an higher range.
8. For HOLD function, Minimum and Maximum value measurement, Peak measurement
(for µAposition) and for Relative measurement (for Aposition) please refer to
paragraph 4.2.
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TM-87/TM-88
4.3.5. Resistance measurement and Continuity Test
CAUTION
Before taking resistance measurements on the circuit remove power from
the circuit being tested and discharge all capacitors.
Fig. 6: Using the instrument for Resistance measurement and Continuity test
1. Selecting the position Ω.
2. Insert the test leads into the jack, the red plug into HzVΩµAjack and black plug into
COM jack (see Fig. 6).
3. Connect the test leads to the circuit under test. The resistance value is displayed.
4. Pressing the R/SEL key to select the correct range or using the Autorange feature (see
paragraph 4.2.4). If the resistance value under test is unknown, select the highest
range.
5. If the message "O.L" is displayed a higher range must be selected.
6. The continuity test is always active and the test is performed using the test leads in the
same way of resistance measurement. The buzzer is on for resistance values <35Ω.
7. For HOLD function, Minimum and Maximum value measurement and Relative measure
please refer to paragraph 4.2.
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TM-87/TM-88
4.3.6. Diode test
CAUTION
Before taking diode test on remove power from the circuit being tested and
discharge all capacitors.
Fig. 7: Using the instrument for Diode test
1. Selecting the position .
2. Insert the test leads into the jacks, the red plug into HzVΩµAjack, and black plug
into COM jack.
3. Connect the test leads to the diode under test observing the proper polarities (see Fig. 7).
The threshold voltage value of direct polarization is shown at display. The meter
displays the diode voltage to approximately 0.4 ~ 0.9V for good junction.
4. If the threshold voltage value is 0V the diode P-N junction is shorted circuit.
5. If the message “ O.L." is displayed the diode terminals are reversed or the diode P-N
junction is damaged.
6. For HOLD function, Minimum and Maximum value measurement and Relative measure
please refer to paragraph 4.2.
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TM-87/TM-88
4.3.7. Capacitance measurement
CAUTION
Before taking capacitance measurements in circuit remove power from the
circuit being tested and discharge all capacitors. Use the short test lead pair
for measurement to reduce the stray capacitance. Before connecting the
test capacitor observe the display, which may have a reading other than
zero every time the range is changed. Subtract this offset reading from the
displayed reading of the test result of a capacitor to obtain the true value.
Connect the test capacitor to the inputs respecting the polarity connections
when required. Due to internal delay time, bargraph it’s no operative in
capacitance measurement.
Fig. 8: Using the instrument for Capacitance measurement
1. Selecting the position .
2. Insert the test leads into the jacks, the red plug into HzVΩµAjack and black plug
into COM jack (see Fig. 8).
3. Connect the red and black test clamps to the capacitor terminals respecting if
necessary the proper polarities. The capacitance value is shown on display.
4. Pressing the R/SEL key to select the correct range or using the Autorange feature
(see paragraph 4.2.4). If the capacitance value under test is unknown, select the
highest range.
5. If the message "O.L" is displayed the maximum readable value is reached.
6. For HOLD function, Minimum and Maximum value measurement and Relative
measure please refer to paragraph 4.2.
15

TM-87/TM-88
4.3.8. Frequency measurement
CAUTION
The maximum input for AC voltage is 750Vrms. Do not attempt to measure
higher voltages to avoid electrical shocks or damages to the instrument.
Fig. 9: Using the instrument for Frequency measurement
1. Selecting the position Hz.
2. Insert the test leads into the jacks, the red plug into HzVΩµAjack and black plug into
COM jack (see Fig. 9).
3. Connect the test leads to the circuit under test. The frequency value will be displayed.
4. Pressing the R/SEL key to select the correct range or using the Autorange feature (see
paragraph 4.2.4). If the freqency value under test is unknown, select the highest range
5. If the message "O.L" is displayed the maximum readable value is reached.
6. For HOLD function, Minimum and Maximum value measurement and Relative measure
please refer to paragraph 4.2.
16

TM-87/TM-88
4.3.9. Temperature test (Only for TM-88)
CAUTION
The maximum input of AC voltage is 24Vrms DC voltage is 60V. Do not
attempt to measure higher voltages to avoid electrical shocks or damages
to the instrument.
Fig. 10 : Using the instrument for Temperature test
1. Selecting the position ℃/℉.
2. Pressing the R/SEL key to select the℃and ℉readings.
3. Insert the banana plug adapter T10 with correct ＋plug into VΩHzµA℃℉ jack,
and －plug into COM jack. with banana pins to K-type socket to adapt other standard
K-type mini plug temperature probes.
4. Connect the other ends of temperature test leads for temperature measurement.
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TM-87/TM-88
5. MAINTENANCE
5.1. GENERAL INFORMATION
This is a precision instrument. To guarantee its performances be sure to use it according to
these instructions and keep it stored on suitable environmental conditions Do not expose it to
high temperatures or humidity or direct sunlight. Be sure to turn it off after use. If you
expect not to use the instrument for a long period remove batteries to avoid leakages of
battery liquid which could damage its inner components.
5.2. BATTERY REPLACEMENT
When the low battery indication “”is shown the battery it’s to be replaced.
CAUTION
Only skilled technicians can open the instrument and replace batteries.
Before removing batteries disconnect the test leads from the input terminals
to avoid electrical shocks.
LEGEND:
1. Disconnect the test leads from the
input terminals.
2. Remove the fixing screws from the
back case and detach it.
3. Remove the battery replacing it with
new one (9V NEDA1604, JIS006P,
IEC6F22) respecting the polarity
signs and replace the back case
and screws. Use the appropriate
battery disposal methods for your
area.
Fig. 10: Battery replacement
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TM-87/TM-88
5.3. FUSE REPLACEMENT
CAUTION
Before replacing fuses, disconnect test leads from any energized circuit to
avoid electrical shock.
LEGEND:
1. Turn OFF the meter and
disconnect the test leads from the
input terminals.
2. Unscrew the four fixing screws of
the back holster and remove it.
3. Remove the defective fuse and
install a new fuse of the same size
and rating (fast 10A/1000V
Bussmann type). Make sure the
new fuse is centered in the fuse
holder. Re-screw the back holster.
Fig. 11: Fuse replacement
5.4. CLEANING
To clean the instrument use a soft dry cloth. Never use a wet cloth, solvents or water.
5.5. END OF LIFE
Caution: this symbol indicates that equipment and its accessories shall be
subject to a separate collection and correct disposal.
19