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General description
The HMI -1 EMF meter is a small, 120mm x 60mm x 25mm,
handheld triaxial instrument for measuring power frequency magnetic
fields. The HMI -1 EMF meter has
a number of advanced features: it performs a harmonic analysis
on the magnetic field and also collects statistical information
on the field values measured while the EMF meter is switched on.
The HMI -1 EMF meter measures the magnetic field in three axes and automatically
calculates the resultant field. The instrument is auto-ranging and
can measure resultant fields up to 6000mG. True RMS quantities are
used for all readings. In addition to broadband measurements, the
HMI -1 EMF meter calculates fundamental power frequency and third harmonic
components of the field, as well as the totality of fundamental
and power frequency harmonics. The displayed reading updates once
per second. |
| The HMI -1 EMF meter uses a 16X2 character LCD
alphanumeric display. A push button switch on the front of the
instrument cycles
the display through six screens. This allows a great deal of information
to be displayed to the user. |
While the HMI -1 EMF meter is primarily a survey
meter and has no external connections, it collects statistics
on the field while switched on. The percentage
distribution of the broadband resultant RMS field readings in eight
"bins", (0 - 4 mG, 4 - 10, 10 - 30, 30 -100, 100 - 300,
300 -1000, 1000 - 3000, 3000 - 6000), is collected and displayed
on one screen. Also minimum, maximum, average and standard deviation
values of the field during the time the meter is switched on are
recorded. This statistical data is retained under low battery voltage
condition. |
The HMI -1 EMF meter uses a standard 9 volt alkaline battery
and the average current drain is less than 10
mA. |
HMI - 1 EMF meter specifications |
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| Measurements: True RMS magnetic
flux density in three axes and resultant.
Accuracy: ± 2% ± 1 digit typical
for a 50 Hz sinusoidal field.
Frequency response: 30 Hz – 1000 Hz (+ 1dB,
- 3dB relative to 50 Hz response) |
Autoranges between three measurement
ranges:
| 0 - 99.9 mG |
0.1 mG resolution |
| 100 - 999 mG |
1 mG resolution |
1000 - 6000 mG |
1 mG resolution |
|
Resolution of broadband field into:
- power harmonics
- fundamental (50 Hz) frequency component
- third harmonic (150 Hz) frequency component
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Calculation of statistics of broadband
field readings since switch on:
- Min, Max of broadband RMS values
- Mean and Standard Deviation of broadband RMS field values
- Records percentage of broadband RMS field values in eight ranges:
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0 - 4 mG |
4 -10 mG |
10 - 30 mG |
30 - 100mG |
100 - 300 mG |
300 - 1000 mG |
1000 - 3000 mG |
3000 - 6000 mG |
|
- Elapsed time since switch-on
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Provision for retention of statistical data
under low battery condition. |
Battery life: Greater than 48 hours
continuous use from a standard 9 volt alkaline battery. Battery
current consumption is less than 10 mA (averaged over one second). |
Operating Environment: - 5 °C
to + 50 °C, up to 90% RH |
Size: 120mm x 60mm x 25mm |
Weight: 95 grams (without battery) |
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