Delta OHM HD 2020 Manual

HD 2020

ACOUSTIC CALIBRATOR

The HD 2020 sound level calibrator is a portable, battery operated sound source, suitable
for sound level meters (portable and laboratory) and acoustic stations. It allows calibrating
½" microphones with mechanical dimensions compliant with IEC 61094-1 ("Measurement
microphones. Part 1: Specifications for laboratory standard microphones") and IEC 61094-4
("Measurement microphones. Part 4: Specifications for working standard microphones"). The
calibration pressure levels of 94dB and 114dB can be selected by the keypad. The 1000 Hz
frequency cannot be changed.
If the microphone is absent or not inserted correctly into the calibrator cavity, the sound level
will blink on the display.
To conserve battery life, the instrument is provided with an automatic power off function: if you
leave the instrument on with open cavity, it switches off automatically after 30 seconds. If the
cavity is closed and the microphone is inserted, the instrument switches off 5 minutes after
turning on, provided that you don't press any key.
The calibrator display shows calibration pressure level, battery life, current date and time.
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AV-18
HD 2020
The clock/calendar allows you to set the number of years and months of validity of the
calibration from the date of adjusting: at the expiration time, an appropriate symbol flashes
on the display.
ACOUSTIC CALIBRATOR
1. ON-OFF key: turns on and off the instrument. When you turn the instrument on, the display
will switch on about three seconds later.
2. SETUP key: allows you to enter and scroll menu. To exit, press it repeatedly until you go
back to the standard screen.
3. Display. When you turn the instrument on, it shows all segments on, and then the sound
pressure level (94 or 114dB) will appear in standard view.
4. Calibrator cavity for conventional ½ inch microphones.
5. ▼ key: in standard mode, it selects 94dB and 114dB pressure levels alternately. In menu
mode, it decreases the current value.
6. ▲ key: in standard mode, it selects 94dB and 114dB pressure levels alternately. In menu
mode, it increases the current value.
7. Battery lid.
Advantages of the HD 2020 calibrator are:
• The 1000Hz frequency allows calibrating sound level meters with any weighting (LIN, A, B,
...), without applying any correction factor.
• The calibration sound pressure level is independent of atmospheric pressure: you don't
need to adjust the value according to static pressure over a wide range of values.
• The HD 2020 calibrator can be conveniently used both in laboratory and in the field. The 114
dB sound level allows performing calibrations even in high background noise environments.
• Its simplicity of use allows the use even by unskilled personnel.
• The presence of the LCD helps you through the steps of setting the calibrator, signal the end
of the span and allows you to check the status of the battery.

DESCRIPTION KEYBOARD AND DISPLAY

The keyboard instrument consists of 4 buttons.
The following describes in detail the functions performed by each.
ON
O F F
Press the ON/OFF key to turn the instrument on and off.
When instrument is on, all display segments are shown for a few seconds,
...an auto-test including the level of battery charge starts and brings the instrument to the
standard working condition.
Note: between the instant when you press the ON / OFF button and switching the display
pass about three seconds: this time it is necessary to perform the initial self-test.

Auto-off feature

The instrument has the auto-off feature (Auto-Power Off) that turns the meter off after 5
minutes if, in this interval, the microphone is inserted into the cavity of the calibrator and
press any button.
If the cavity is open, indicating the noise level in the display: in these conditions the instrument
will turn off automatically after 30 seconds
The Auto-off feature cannot be excluded.
SETUP
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The SETUP key allows entering and viewing the menu. To exit, press the SETUP key until you
go back to the standard screen, or keep it pressed for more than 2 seconds.
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The menu shows:
• Current date and time in the format year, month, day, hour, minute, second.
• Current date and time in the format year, month, day of the last calibration.
• The interval between the calibration date and the expiry date in years and months.
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ON-OFF key
HD 2020
HD 2020
94

SETUP key