7–8 Minimate Pro Operator Manual
Range Automatic +/- 100 Pa (Normal), +/- 25 Pa
(Sensitive)
Trigger Levels 33 dB - 140 dB 0.448 - 100 Pa (Normal), 0.0142
Pa - 25 Pa (Sensitive)
Sample Rate 1024 sps Recommended 64 Ksps Recommended
Cable Length 6 ft. (2 m) 6 ft. (2 m)
Maximum Amplitude 160 dB 160 dB
3. The microphone reference point is at the center of the diaphragm of the microphone.
a. As the microphone was designed to be omni-directional, there should be minimum
angular variation in the microphone response at low frequencies. Sound diffraction
on the microphone face only has a significant effect on the response for frequencies
above approximately 3.5 KHz. The nominal correction curves, for specific angles,
and provided in the following graph. The top curve is for zero degrees, i.e. the
microphone face is perpendicular to the plane acoustic wave. The correction is
subtracted from the response. Below is a chart representing Sound Level
Microphone Angular Response and the Free Field Angular Corrections in Hz:
4. The minimum trigger level is set as 33 dB, which is 3 dB above the minimum detectable
sound level. This provides a margin against false triggering by self-generated noise.
5. Overload Indicator: Input that is greater than 140 dB is replaced by the “*” character in the
data listing. Range switching within the 30 dB to 140 dB range is automatic.
6. Displayed values (including Overload and Under-range indicators) are held until the trigger is
exceeded again, or until the end of the subsequent period of recording the Event.
7. The average self-generated noise level has been measured at 29 dB. The noise level of the
acoustic element is below this, about 24 dB.
8. The nominal drift of the Time of Day display on the monitor over a 24 hour period is 0.2
seconds.
9. When applied to levels specified by IEC 61000-4-2 (Industrial), ESD has no impact on
product operation or accuracy in data.
10. The product meets all (60Hz) immunity requirements of:
a. IEC 61000-4-6 (Industrial) for conducted RF
b. IEC 61000-4-5 (Industrial) for surge
c. IEC 61000-4-4 (Industrial) for bursts
d. IEC 61000-4-3 (Industrial) for EMI compatibility
11. The level linearity error, over 20 dB (measured at 2 KHz) is +/-0.4 dB.
12. The highest sound pressure that will generate a linear response is 140 dB. Electrically, this
corresponds to a 12 Vpp signal from the acoustic element.
13. When the Sound Level Microphone is operating in Advanced Mode (i.e. when raw acoustic
data is input to the monitor), the response matches the response of the acoustic element
(within 3 dB) over the frequency range 10Hz – 20 KHz.
14. Factory calibration testing is done at both the A-Weighting and C-Weighting, to ensure
linearity of response during automatic range switching,
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General