Model
407780
‐
EN
v2.3
1/14
9
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) “A” weighting.
•
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).
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 600
for AC and 100
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.
Tip
Sleeve
Mono
Tip
Ring
Sleeve
Stereo
