Velleman DVM13MFC2U Manual Del Usuario página 3

Frequency Measurement
1. Select channel A or channel B (depending on the range being measured) and connect it to the signal source by means of the cable.
2. Press the AC/DC COUPLING key if the frequency of the signal to be measured is less than 100Hz.
3. If the input signal is high, press the ATT key to ensure that the DVM13MFC2U will measure an attenuated signal.
4. When the FUNCTION key is pressed, the last digit display value is the current selection step.
The frequency measurement has only 3 steps.
5. Complete steps 1 to 3 and press the CONFIRM key. The DVM13MFC2U displays the measurement results.
6. Adjust the gate time.
7. When measuring a 100Hz signal, the device will automatically start measuring the period and display the measuring results.
Period Measurement
Press the PERIOD key. The device will start measuring the period and display the test results.
5. Examples
• Connect the DVM13MFC2U to the mains (110V/220V AC).
• Switch on the device with the ON button and preheat it for 20 minutes.
• Connect the test cable with the input port on the front panel. Select channel A or B according to the frequency range.
• Select the proper function and gate time. The shorter the gate time, the faster the frequency measurement but the lower the resolution.
The longer the gate time, the slower the frequency measurement but the higher the resolution.
• Press PERIOD to measure the period. Confirm by pressing the CONFIRM key. The device starts measuring.
Example 1: Measuring an analogue handset
Connect the test cable with the input from channel B and set the FUNCTION key to the 1-step position. Select the gate time (adjust manually
from 100 msec to 10 sec). The LED display will read:
Example 2: Measuring a 30Mhz
Set the FUNCTION to the 2-step position and select the gate time (adjust manually from 100 msec to 10 sec). The LED display will read:
Example 3: Measuring a self-oscillating frequency (e.g. from a telephone, intercom etc.)
Set the FUNCTION key to the 2-step position. Connect one end of a cable with 5pF capacitance to the red clamp; use the other end to
measure the frequency by touching the contact point.
6. Warnings
• When measuring a high-voltage or strong RF signal, make sure that the cables are in series and have a large capacitance to avoid
damage.
• Press the RESET button once to reset the device or turn off the device in case the device is not working appropriately.
• When there is no input signal, the display may not necessarily read "0". This is absolutely normal and does not affect the measurements
or the accuracy.
• Do not expose the device to extreme temperatures, humidity, dirt, dust etc. Do not open the device to avoid lethal electroshocks.
• A strong interference will reduce the sensitivity when measuring.
DVM13MFC2U
1-step
900MHz
intercom emission frequency
2-step
30MHz
- 3 - VELLEMAN