407780 Datasheet, PDF (9/13 Pages) Extech Instruments Corporation. – Integrating Sound Level Datalogger

Calibration
Calibrating the Model 407780 Integrating Sound Level Datalogger
requires an acoustical calibrator such as the Extech Model 407766 or
407744.
1. Configure the meter as follows:
• Display: SPL (dBA)
• Time weighting mode: FAST
• Measurement mode: INST
2. Insert the 407780 microphone into the opening of the acoustical
calibrator.
3. Adjust the 407780 calibration potentiometer until the 407780
display matches the acoustical calibrator output signal (typically 94
or 114dB).
Maintenance & Cleaning
• Service not covered in this manual should be performed by qualified personnel
• Periodically wipe the case with a dry cloth. Do not use abrasives or solvents.
Analog output
The 407780 has two analog output jacks located on its right side; one for AC and one for DC.
For DC, the meter transmits 10mv / dB. For AC the full scale value is 0.707V. The output
impedance is 600Ω for AC and 100Ω for DC.
The supplied 3.5mm stereo mini-plug can be used to assemble a cable to connect to either of
the meter’s analog output jacks. When using a stereo plug, like the one supplied, short the
Tip and the Ring (see diagram below). Ground (negative) connects to the Sleeve while the
positive signal is taken from the Tip/Ring. For mono plugs, ground connects to the Sleeve
while the positive signal is taken from the Tip. The meter output can then be transmitted to a
headset, chart recorder, datalogger, or other data storage device.
Sleeve Tip
Stereo
Sleeve Tip
Mono
Ring
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Model 407780 Version 2.1 09/07