Digital Tachometers RPM speed measurements of rotating objects

Follow the steps below to replace the battery

1) Turn off the instrument power supply.

2) Remove all test leads from the input socket.

3) Unscrew the captive screws of the battery cover and remove it.

4) Remove the battery cover.

5) Replace the new 6F22 9V battery

6) Install the battery cover as it is, tighten the screws.

Function selection

1) In the voltage range, press "FUNC" key, will be in the AC voltage, DC voltage cycle between the switch.
2) In the resistor, diode, buzzer file, press the "SEL" button, will be in the resistance, on-off detection, diode three file cycle switch.
3) In the frequency, duty cycle file, press the "FUNC" key, will be in the frequency, duty cycle between the switch.
4) In the temperature range, press the "FUNC" key, will be in degrees Celsius and Fahrenheit cycle switch.
5) In the current file, press "FUNC" key, will be in the AC current, DC current cycle between the switch

backlight and lighting

1) During the measurement, if the ambient light is too dark, the reading is difficult, press the " " button for more than 2 seconds, turn on the backlight and the lights, and turn off automatically after about 15 seconds.
2) During this period, if the " " button for more than 2 seconds will manually turn off the backlight and lighting.
Backlight and lighting of the luminous body for the LED, the working current is large, although the instrument has a timer circuit (timing time of about 15 seconds), but often use the backlight and lighting will shorten the battery life, so unnecessary Of the circumstances, should be used as little as possible backlight.

Technical indicators

Ambient temperature: 23 ± 5 ℃ Relative humidity: <75%
3.2.1 True rms zero input
3.2.1.1 The measurement of sine wave signal, the use of true RMS measurement method than the traditional average response method error is small.
3.2.1.2 True RMS The instrument can accurately measure the sine wave signal, but if it is on the AC function, the instrument may display 1 to 50 if the measured signal is not input (shorted at the AC voltage range and the input terminal) Word between a reading. These deviations are normal. Within the specified measuring range, they do not affect the accuracy of the multimeter to measure alternating current.
3.2.1.3 True RMS requires that the input signal reach a certain level for measurement. Therefore, the AC voltage and current range is specified between 2% and 100% of full scale.



3.2.2 DC voltage

- Input impedance: 10MΩ
- Maximum input voltage: 600V DC or 600V AC (rms)
Note:
In the small voltage range, the pen is not connected to the circuit under test, the instrument may have beating the reading,
This is normal, this is because the instrument caused by high sensitivity, does not affect the actual measurement results.

3.2.3 AC voltage

- Input impedance: 10MΩ

- Maximum input voltage: 600V AC (RMS) or 600V DC

- Frequency range: 40 ~ 1000Hz True RMS

Note:
In the small voltage range, the pen is not connected to the circuit under test, the instrument may have beating the reading,
This is normal, this is because the instrument caused by high sensitivity, does not affect the actual measurement results.



3.2.4 Alternating current

- Overload protection: mA range fuse (self-recovery fuse 200mA / 250V)
10A range without insurance
- Maximum input current: mA: 600mA DC or AC rms;
10A: 10A DC or AC rms;
When the measured current is greater than 5A, the continuous measurement time is not longer than 15 seconds, after the measurement to stop the current measurement for more than 1 minute.
- Frequency response: 40Hz ~ 1000Hz True RMS.

3.2.5 DC

- Overload protection: mA range fuse (self-recovery fuse 200mA / 250V)
10A range without insurance
- Maximum input current: mA: 600mA DC or AC rms;
10A: 10A DC or AC rms;
When the measured current is greater than 5A, the continuous measurement time is not longer than 15 seconds, after the measurement to stop the current measurement for more than 1 minute.


3.2.6 Frequency

- Overload protection: 250V DC or AC (rms)
- Input voltage range: 600mV ~ 10V AC (with the measured frequency increases, the input voltage should also increase)


3.2.7 Duty cycle

- Frequency response: 10 ~ 10MHz

- Input voltage range: 600mV ~ 10VAC (with the measured frequency increases, the input voltage should also increase)

- Maximum input voltage: 250V AC (rms)

Resistance

- Open circuit voltage: approx. 1.0V
- Overload protection: 250V DC or AC (rms)

Transistor test

Capacitance

- Overload protection: 250V DC or AC (rms)

Temperature test

- Overload protection: 250V DC or AC (rms)