MESTEK DM100C Digital Multimeter User Manual

MESTEK DM100C Digital Multimeter

OVERVIEW

This instrument is a 9999-counter, hand-held digital multimeter with true virtual value and manual Automatics integration. It has a large, double, in vert digital LCD display with simulation bars and illumination lights which are easy for users to read. It has the functions of alarm for fuse tube fused, wrong insertion of measurement probe, overload protection and batt hereunder voltage indication. It is an ideal multifunction instrument forfeit her professionals, factories, schools, enthusiasts or families. It is designed and manufactured according to the safety requirement for electronic measuring instruments and handheld digital multimeters specified in the international electrical safety standard IEC-61010.1t meets the requirements of IEC61010’s 600V CAT IV, 1000V CAT. Il and Pollution Degree 2. Before using the instrument, please read the instruction manual carefully and pay attention to the safe working practices.

Safety Information

Safety Instructions
When using this instrument, the user must observe all standard safety procedures for the following two aspects: A Safety procedure for preventing electric shock. B Safety procedures for the prevention of incorrect use of the instrument. To ensure your personal safety, please use the measurement probe provided with the instrument. Check and make sure they are intact before use.

Safety Precautions
When using the instrument near a device with large electromagnetic interference, the reading of the instrument will be unstable. A large error may occur. Do not use the instrument or the measurement probe when its appearance is damaged. If the instrument is not used correctly. the safety functions provided by the instrument may expire. You must be extremely careful when working around bare conductors or buses. Do not use the instrument near explosive gas, steam or dust. Measurements must be taken using the correct input terminal, functions, and ranges.

• The input value must not exceed the input limit specified for each range to prevent damage to the instrument.
• When the instrument is connected to the line to be tested, do not touch the input terminal that is not used.
• When the measured voltage exceeds 60Vdc or 30Vac RMS, operate carefully to prevent electric shock.
• When measuring with a measurement probe, place your finger behind the guard ring of the measurement probe.
• Before converting the range, you must ensure that the measurement probe has left the circuit under test.
• For all DC functions, to avoid the risk of electric shock due to possible incorrect readings, use the AC function first to confirm the presence of any AC voltage. Then, choose a DC voltage range equal to or greater than the AC voltage.
• Before performing resistance, diode, capacitance measurement or make -and-break test, the power of the circuit under test must be cut off and all high voltage capacitors in the circuit under test must be discharged.
• Do not measure resistance or perform make-and-break tests on live circuits.
• Check the fuse tube of the instrument before making current measurements. Before connecting the instrument to the circuit under test, turn off the power of the circuit under test.
• When performing TV service or measuring the power-switching circuit, you must be careful of the high voltage pulse in the circuit under test to avoid damage to the instrument.
• This meter is powered by 2 sets of 1.5V AA batteries, which must be correctly installed in the battery compartment of the instrument.
• When the battery under voltage symbol appears, replace the battery immediately. Insufficient battery power can cause incorrect instrument readings that can result in electric shock or personal injuries.
• Do not exceed 1000V when making measurement category Ill voltage measurement; do not exceed 600V when making measurement category IV voltage measurement.
• Do not use the instrument when the outer casing (or part of the outer casing) of the instrument has been removed.

Security Symbol:

• Refer to the instruction manual for warning, important safety mark before usage. Incorrect usage can result in damage to the device or its components.
• AC (alternating current)
• DC (direct current)
• AC or DC
• Earth
• Double insulation protection
• Fuse
• Conforms to the directives of European Union
• High voltage warning
• Disconnected fuse tube

CAT. II Class ll| 1000 V overvoltage protection
CAT. IV Class IV 600 V overvoltage protection

Safe maintenance habits

Safe maintenance habits

• When opening the instrument case or removing the battery cover, first pull out the measurement probe.
• When repairing the instrument, the specified replacement parts must be used.
• Before turning on the instrument, you must shut down all relevant power sources, and you must also ensure that you do not have static electricity to avoid damaging the components of the instrument.
• Calibration and maintenance of the instrument can only be performed by professionals.
• When opening the casing of instrument, it must be noticed that some of the capacitors in the instrument retain dangerous voltages even after the instrument is turned off.
• If any abnormality is observed on the instrument, the instrument should be immediately disused and sent for repair, and make sure that it cannot be used until it passes the inspection.
• When it isn’t used for a long time, please remove the battery and avoid storing it in a place with high temperature and humidity.

Input protection measures

• *The maximum input voltage that can be withstood is 1000V DC voltage or 750V AC voltage when making voltage measurement.
• an AC voltage of less than 600V or equivalents voltage can be withstood when making measurements on frequency, resistance, on-off and diode.
• • it can be protected by a fuse tube(F600mA/250V) when measuring HA Current and mA current.
• In order to avoid damage to the instrument, if the red instrument is inserted by mistake into the current jack in other gears except the current gear, the screen will show LE Ad, and the buzzer will give an alarm, prompting the measurement probe to be inserted in a wrong jack. At this time, the red measurement probe should be reinserted in the right jack once again for measurement.
• In the  UA and mA gear, if the fuse tube is fused, the screen will display FUSE and the symbol. prompting that the fuse tube is disconnected after the measurement probe is inserted into/mA jack. At this time, the fuse tube of the corresponding specification needs to be replaced again before the measurement can be continued. The same prompt function is also available in the 1OA current gear.

INSTRUCTIONS FOR INSTRUMENT INDICATION

Schematic diagram of the Instrument

1. Non-contact voltage sensing area
2. Non-contact voltage indicator light
3. Liquid-crystal display
4. SEL Button
5. Hold Button
6. .Flashlight Button
7. VFC Button
8. Range Rotary Knob
9. 10A Terminal
10. mA/uA Terminal
11. VQ t*Live Hz % C/F Terminal

Symbols Description

• Battery under voltage/ low battery
• Automatic shutdown function
• High voltage warning
• Negative input polarity
• AC  input
• DC input
• Continuity test mode
• Diode test mode
• AUTO Auto range mode
• HOLD Reading hold
• C/F Voltage Frequency Conversion
• Duty cycle
• NCV Non-contact
• AC voltage detection mode
• VFC Frequency conversion voltage measurement

Description of function button

Description of Input socket

Accessories

OPERATION MANUAL

Normal operation

Reading Hold Mode
The reading hold mode can keep the current reading on the display. The reading hold mode can be exited by either changing the measurement function gear or by pressing the HOLD button only once. To enter and exit the reading hold mode: 1. Press the “H” button, the reading will be held and the” H “symbol will be displayed on the LCD at the same time. 2. Press the” H “button again to return the instrument to its normal measurement state.

Lighting function
The instrument equipped with the lighting function facilitates the user to operate in darker lighting conditions. Turn on or off the flashlight as follows: 1. Press the” ” button to turn on the light. 2. Press the” “button once again to turn off the light.

Frequency conversion voltage measurement function
In the automatic AC and DC voltage gear, press the SEL button to switch to the

AC voltage gear, and then press the V.F.QC button to enter the frequency convers ion voltage measurement function, which can measure the frequency conversion voltage stably.

Automatic shutdown function
The instrument will emit a ticktack sound to automatically cut off the power and go to dormancy state after no operation is taken 15 minutes after starting. Press the SEL and V.F.C buttons in the auto p close-down mode to reboot.

Measurement Guide

The instrument adopts manual/automatic integrated design to measure voltage or resistance by choosing either auto range measurement or manual range measurement.

Measuring AC and DC voltages
Any voltage above 1000V DC or 75OV AC rams can’t be measured to prevent electric shock and/or damage to the instrument. The voltage of more than 1000V DC or 750V AC rams can’t be imposed between the common terminal and earth to prevent electric shock and/or damage to the instrument.

The DC voltage range of this instrument is:999.9mV/9.999V/99.99V/999.9v and 999. 9V; the AC voltage range is: 999.mV, 9.999V, 99.99V and 750V. Measurement of AC or DC voltage:

1. Rotate the rotary switch to the V gear to enter the auto range measurement mode (press the SEL button to switch between AC and DC voltage), or rotate the knob to 1000mV, 10V, 100V, 1000V or 1000mV in V , or 1000mV, 10V, 100V, 750V of V gear, enter manual range measurement mode to measure DC or AC voltage.
2. Connect the black measurement probe and the red measurement probe to the COM input socket and the V input socket, respectively.
3. Use another two terminals of the measurement probe to measure the voltage value of the circuit under test. (connection in parallel with the circuit to be tested)
4. The measured voltage value is read by the liquid crystal display, and the voltage value can be directly displayed in the automatic gear. If the manual voltage gear is used, the knob needs to be rotated to the appropriate gear to read the voltage value. When measuring AC voltage, the display will display both voltage value and frequency values at the same time. When measuring DC voltage, he display will simultaneously display the polarity of the voltage to which the red measurement probe is connected.

Note:

1. Din the 1000mV range of DC and AC, even if the measurement probe isn’t entered or connected, the reading will be displayed on the instrument. In this case, short-circuit the “V-“and” COM” terminals to make the instrument display return to zero.
2. Under the AC voltage function of the auto range, press the V.F.C button to measure the AC frequency conversion voltage.
3. The AC voltage value measured using this instrument is the true RMS (root mean square). For sine waves and other waveforms (no DC offset), such as square waves, triangle waves, and staircase waveforms, these measurements are accurate.

Measuring resistance

• To avoid damage to the instrument or the device under test, turn off all power to the circuit under test and fully discharge all high-voltage capacitors before measuring resistance.

The unit of resistance is ohms (0). The instrument’s resistance range is 999.9, 9.999k, 99.99k, 999.9k, 9.999M, 99.99M. Measuring resistance:

1. Rotate the rotary switch to the gear to the auto range measurement mode, or rotate the knob to 1000,10K,10OK, 1000K,10M, 100M in gear to enter the auto range measurement mode.
2. Connect the black test pen and the red test pen to the COM input socket and the V/ input socket, respectively.
3. Use another two terminals of the measurement probe to measure the resistance value of the circuit under test.
4. Read the measured resistance value from the LCD. The resistance value can be directly displayed in the automatic gear. If the manual resistance gear is used, the knob needs to be rotated to the appropriate gear to read the resistance value.

Note:

1. The measured resistance value on the circuit will usually differ from the rated value of the resistor.
2. When measuring low resistance please short-circuit the resistance of the two shorts to read the shot of the test leads in order to keep the accuracy of the measurement. After measuring the measured resistance, the resistance value needs to be subtracted.
3. In the 10OM gear, it takes a few seconds for stabilizing the reading. This is normal for high resistance measurements.
4. When the instrument is in the open circuit or the resistance of the measured object is too large, the display will show “OL”, indicating that the measured value is out of range.

Test of the Diodes/Buzzer and continuity
To avoid damage to the instrument or the device under test, all power to the circuit under test should be cut off and all high voltage capacitors should be fully discharged before measuring the diode. In order to avoid damage to the instrument under test, al power to the circuit under test should be cut off and all high voltage capacitors should be fully discharged before the buzzer make-and-break test.

1. Tenth rotary switch to the 9ear.
2. Connect the black measurement probe and the red measurement probe to the COM input socket and the VI input socket, respectively.
3. Connect the black measurement probe and the red measurement probe to the two terminals of the object to be tested.
4. The starting mode is continuity test mode only, press the SEL button, switch to diode test mode only, press’s the SEL button again.it switches to continuity or diode test mode, press the SEL button once again, it switches to continuity test mode only.
5. If the object to be measured is a diode, place the red and black measurement probes at the positive and negative terminals of the diode respectively. The instrument will display the forward bias value of the diode under test. If the polarity of the measurement probe is reversed or the polarity of the test point connected to the diode is reversed, the instrument will display OL”. In the circuit, a normal diode should produce a forward voltage drop of 0.5V to 0.8V; however, the reading of reverse bias will depend on the change in resistance of the other channels between the two measurement probes.
6. 1f the resistance of the circuit under test is less than about 1000, the instrument will automatically switch to the continuity measurement mode, When the resistance of the circuit under test is more than about 152, the instrument will automatically switch to the continuity measurement mode, and the indicator light (green light) induced will be on for a long time. The buzzer will make a continuo us sound. When the resistance of the circuit under test is between about 15-300, the indicator light (green light) will fast and the buzzer will make discontinuous Sound.

Measuring capacitance

To avoid damage to the instrument or the device under test, turn off all power to the circuit under test and fully discharge all high-voltage capacitors before measuring electric capacity. The DC voltage gear is used to determine that the capacitors have been discharged.

The instrument’s capacitance range is 9.999nF, 99.99nF, 999.9nF, 9.999uF 99.99 F and 999.9uF.9.999mF, 99.99mF. Measuring capacitance:

1. Turn the rotary switch to the t gear.
2. Connect the black measurement probe and red measurement probe to the COM input socket and Input socket respectively.
3. Use another two terminals of the measurement probe to measure the electric capacity value of the electric capacity to be tested, and read the measured value from the liquid-crystal display. Note: Owen measuring large capacitance, it takes time to stabilize the reading.

When measuring the electric capacity with the polarity, pay attention to the corresponding polarity and avoid damage to the instrument.

Measurement frequency

Do not measure any frequency of the voltage above 250V DC or AC rams to prevent electric shock and/or damage to the instrument.

Measuring frequency:

1. Rotate the rotary switch to the HZ% position.
2. Connect the black measurement probe and the red measurement probe to the COM input socket and the Hz input socket, respectively.
3. Measure the frequency value of the circuit under test with another two terminals of the measurement probe. 4. Read the frequency value from the LCD. The frequency and duty cycle values are displayed simultaneously.

Measuring current

When the open-circuit voltage to the earth exceeds 250V, be sure to not attempt to make current measurements on the circuit, If the fuse is burnt out during the measurement, you may damage the instrument or hurt yourself. To avoid damage to the instrument or the device under test, check the fuse of the instrument before making current measurements. When measuring. use the correct input socket, function gear and range. When the measurement probe is plugged into the current input socket, do not connect the other terminal of the measurement probe in parallel to any circuit

The instrument’s DC current range is 99.99uA, 99.99mA, 600.0mA, 10.00A, the alternating current measuring range is 99.99mA, 600.OmA and 10.00A; Measuring current:

1. Turn the rotary switch to the appropriate gear
2. Connect the black measurement probe to the COM input socket. Connect the red measurement probe to Thea/mA input socket if the measured current is less than 600mA;if the measured current is between 600mA and 10A,connect the red measurement probe to the 10A input socket.
3. Disconnect the circuit to be tested. Connect the black measurement probe to the terminal of the disconnected circuit (with lower voltage) and the red measurement probe to the terminal of the disconnected circuit (with higher voltage).
4. Connect the power to the circuit and read the displayed reading. In the AC current gear, the screen simultaneously displays the current value and frequency. If the display only shows “OL”, which means that the input exceeds the selected range, the rotary switch should be placed at a higher range.

NCV test
Rotate the rotary switch to the NCV gear to dose the top of the instrument to the conductor. If the instrument detects the AC voltage, the instrument will light the corresponding signal strength indicator according to the detected signal strength. When the sensed voltage is low, the screen will display-L, the green indicator light is on for a long time. When the sensed voltage is high, the screen displays – H, the two red indicators light up, and the buzzer sounds an alarm at different frequencies.
Note:

1. Even if no indication exists, the voltage mastic exist. Do not rely on non-contact voltage detectors to determine if a wire has a voltage. Detection operations may be affected by factors such as socket design, insulation thickness and type.
2. When the voltage is entered into the input terminal of the instrument, the voltage sensing indicator may also be bright due to the presence of induced voltage.
3. Interference sources in the external environment (such as flashing light, motor, etc.) may trigger non-contact voltage detection by mistake.

Live Line and Natural Line Distinguish

1. Rotate the rotary switch to the Live gear.
2. Connect the red measurement probe to the V input socket.
3. Insert a single measurement probe into the power socket L jack or dose to the live wire. If the instrument detects the AC voltage, it will judge whether the voltage is a firewire according to the detected signal strength. If it is judged to be a live line, the display will send display LIVE and the green indicator light will be on, the buzzer will send an alarm with different intensities.

Temperature measurement
Set the range switch to °C/°F gear and the screen will display normal temperature. You can also insert the red plug of the thermocouple into the C terminal and the black plug into the COM jack. When the reading is stable, the temperature value can be read directly from the display. The default unit of this gear is “C, press SEL button to switch to °F.

TECHNICAL INDICATORS

Comprehensive indicators

Environmental conditions for usage 600V CATIV and 100OV CAT. Ill Pollution degree: 2 Altitude above sea level< 2000 m. Temperature and humidity in the working environment: 0-40 OC (-80% RH, it isn’t considered when <10°C). Storage environment temperature and humidity -10-60 OC (when <70% RH, remove the battery). Temperature coefficient: 0.1 accuracy/OC (<18 OC or >28 OC).

• Maximum allowable voltage between the measuring terminal and the earth: 1000V DC or 750V AC RMS
• Protection of the fuse tube: mA gear: fuse tube FF 600mA/250V; A-gear fuse tube FF 10A/250V
• Conversion rate: about 3 times / second
• Display: 9999 counts displayed by LCD. The unit symbol is automatically displayed according to the measurement function gear,
• Overage indication: The LCD will display “OL.
• Indication for low voltage battery: When the battery voltage is lower than the normal working voltage, “will be displayed. Indication of input polarity:”” is automatically displayed.
• Power supply: 2 x 1.5V AA battery
• External dimensions: 185x88x52mm
• Weight: about 350g (including battery).

Precision Index

Accuracy: (% reading+ word), the warranty period is one year from the date of delivery. Reference conditions: ambient temperature 18° C to 28C, relative humidity is not more than 80%.

DC voltage

• Input impedance: 10M Maximum
• input voltage: 1000Vdc or 750Vac rms.
• Input impedance : 1OM
• Maximum input voltage: 1000Vdc or 750Vac rms.

1AC voltage

• Input impedance: 1OM
• Maximum input voltage: 1000Vdc or 750V ac rms.
• Frequency response: 40Hz-1KHz true RMS (VFC: 2KHz attenuation -3dB)

Frequency

• Range of Input voltage: 200mV-10V ac RMS
• Overload protection: 600V DCIAC

Resistance

Diode

• Overload protection: 600V DCIAC

Buzzer and continuity Test

• Overload protection: 600V DCIAC

Capacitance
Overload protection: 600V DCIAC

Direct current

• Overload protection: mA range fuse tube (FF630mA/250V);10A range fuse tube (FF10A/250V).
• Maximum input current: mA gear: 600mA DC or AC RMS; 10A gear: 10A DC or AC RMS
• When the measured current is greater than 5A, the continuous measurement time is no longer than 10 seconds, and the current measurement must be stopped for 1 minute after the measurement.

Alternating current

Overload protection: mA range fuse (FF630mA/250V); 10A range fuse (FF10A/250V). Maximum input current: mA gear: 600mA DC or AC RMS; 10A gear: 10A DC or AC RMS When the measured current is greater than 5A, the continuous measurement time is no longer than 15 seconds, and the current measurement must be stopped for 1 minute after the measurement. Frequency response: 40Hz- 1KHz, true RMS

Temperature

Overload protection: 600VDCIAC 5.

Instrument maintenance

This section provides basic maintenance information, including instructions for replacing the fuse and replacing the battery. Do not attempt to repair the instrument unless you are an experienced service man with relevant calibration. performance testing, and maintenance information. This section provides basic maintenance information, including instructions for replacing the fuse and replacing the battery. Do not attempt to repair the instrument unless you are an experienced service man with relevant calibration, performance testing, and maintenance information. To avoid electric shock or damage to the instrument, do not wet the inside of the instrument. The connection wire between the measurement probe and input signal must be removed before opening the case or battery cover. Regularly clean the case of the instrument with a damp clothed small amount of detergent. Do not use abrasives or chemical solvents. Input sockets that are dirty or damp may affect readings.

Cleaning the input socket:

• Turn off the instrument and pull all the measurement probes out of the input socket.
• Remove any dirt from the socket.
• Use a new cotton ball dipped in detergent or lubricant to clean each socket.

The lubricant can be used to prevent socket contamination relevant to the moisture.

To avoid electric shock or personal injury caused by incorrect readings, replace the battery immediately when the” “symbol appears on the display of the instrument. One-use the specified fuse (600mA/250V, 10A/250V fast-thawing fuse) To avoid electric shock or personal injury, turn off and check that the measurement probe has been disconnected from the measurement circuit before opening the battery cover and replacing it with a new one.

Please replace the battery according to the following steps:

1. Turn off the power of the instrument.
2. Pull all the measurement probes out of the input socket.
3. Loosen the screws that secure the battery cover with a screwdriver.
4. Remove the cover of the battery.
5. Replace with a new 2 x 1. 5VAA battery
6. Install the battery cover and tighten the screws.

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