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Instantel
Field Calibration
The Micromate monitoring unit provides an option to calibrate the Sound Level
Microphone in the field. A field calibration only uses one reference signal of 94 dB
at 1 kHz. (The Brüel & Kjaer Sound Calibrator Type 4231 is also capable of generating
a 114 dB signal, make sure you set the device to 94 dB at 1 kHz.) A successful field
calibration will store the values for Sound Pressure, Gain and Offset on the hardware
of the microphone, if there is an error during calibration, no values are overwritten.
In this case you can either try again or have the Sound Level Microphone calibrated
at Instantel or one of its authorized calibration facilities. Reports generated by
the Micromate monitoring unit will specify the serial number, calibration date and
calibration method.
Example:
Factory Calibration:
UA12345, January 1, 2022 by Instantel
Field Calibration:
UA12345, January 1, 2022 by Field Calibration
Note: Swapping Sound Level Microphones from one Micromate unit to another Micromate unit is permitted. As
calibration values are stored on the Sound Level Microphone, this will not impact any Micromate unit settings.
Field Calibration Procedure
1. Turn on the Micromate unit and connect the Sound Level Microphone, then press the
Setup
key on the unit.
2. Tap
Maintenance Menu
then scroll down and tap
Calibrate Sound Level Microphone.
3. Follow the field calibration device’s operator instructions to properly join the microphone with the field
calibration unit. Set the reference to 94 dB at 1 kHz then turn the calibrator on.
Note: When using either of the three 94 dB field calibrators, it is recommend that the ambient noise be at least 30 dB
lower than this reference signal.
For additional information please see
https://www.pcb.com/Contentstore/mktgcontent/WhitePapers/
WPL_36_Acoustic_methods_calibration_PCB.pdf
4. Tap the
Calibrate
button on the Micromate monitoring unit screen.
5. Tap the
Checkmark
key to confirm the
Proceed with calibration
popup box. This will display
Running Calibration
.
6. When the calibration is finished, the Micromate unit will display
Field Calibration Complete
along with the
values for the measured
Sound Pressure, Gain, and Offset
.
7. In the
Field Calibration Complete
confirmation box, tap the
Checkmark
key.
Important Notes:
•
Only use an Instantel recommended calibration device (see the Tools and Materials Required section).
• Remove the microphone’s windscreen
before
attaching it to the field calibration device, as this can
impede proper calibration.
• Slide the Sound Level Microphone into and out of the field calibration device
without
twisting either end.
• Before reinstalling the Sound Level Microphone in the field,
hand-tighten
the microphone’s housing
extension and cap.
Calibration
The Sound Level Microphone
must be sent
to a manufacturer certified calibration facility, or Instantel headquarters
for calibration. Please visit our calibration facility locator at www.instantel.com. Instantel recommends calibrating all
Sound Level Microphones once a year and provides the Next Calibration dates on the unit and sensors. The factory
calibration process ensures that the microphone is performing as it was designed and accurately measuring
according to the IEC 61672 Class 1 standard.
Using a manufacturer certified facility ensures the proper procedures are followed when calibrating your
microphone. This removes any uncertainty associated with the reliability and measurement accuracy of your
microphone. It also helps ensure the integrity of the measured recorded events if they are ever called upon as
evidence in a court of law. Using unauthorized facilities may have negative legal consequences if the reference
equipment is not traceable, the proper procedures are not followed or if the certification documents are incomplete.
Please visit our calibration facility locator at instantel.com.
Note:
Field calibration is not
as precise as factory
calibration.
The Field Calibration
Procedure will change
the date and
overwrite
the factory calibration
values.
The tracability will then
be linked to the Field
Calibration device.
