HT instruments HT154 - Manual (Page 7)

HT154
EN - 6
4.2. FUNCTION KEY DESCRIPTION
4.2.1. ON/OFF key
Pressing of key permits to turn ON or switch OFF the meter in any moment.
4.2.2. A/C function key
Using the A/C key it is possible to select the A or C frequency weighting:
¾ A weighting: Normally it is used for general sound level measurements.
¾ C weighting: Used for checking the low-frequency content of noise.
4.2.3. LEVEL
key
Cyclically pressing of LEVEL key permits to select the desired range choosing the
herewith values:
¾ 30
÷ 80dB
¾ 50
÷ 100dB
¾ 80
÷ 130dB
The selected range is indicated in the bottom area of LCD.
4.2.4. FAST/SLOW
key
Press the FAST/SLOW key to select the corresponding time integrations. In particular:
¾ FAST: Used for Normal Measurements.
¾ SLOW: Used for checking the average level of fluctuating noise.
4.2.5. MAX/MIN
key
This function allows the instrument to storing the MIN and MAX values of the Sound
Pressure Level. Select the proper range as described in chapter 4.2.2 before using the
MAX/MIN function.
Pressing MAX/MIN key the symbol "MAX" is shown in the top of display. In this mode the
instrument measures and shows the maximum value of the sound Pressure Level. This
value will be automatically updated if a bigger value will occur.
Pressing again the MAX/MIN the symbol "MIN" is shown in the top of display. In this mode
the instrument measures and shows the minimum value of the Sound Pressure Level. This
value will be automatically updated if a lower value will occur.
Pressing MAX/MIN key for at least 1 second to escape this mode and back to normal
measurements.