F.W. Bell 4090 Operating Instructions Manual

III. Specifications

Dynamic Range: 0.1 mG to 1999 mG, RMS,
autoranging over four decades (20,000:1). 199.9 mG
full-scale with 0.1 mG resolution in high-sensitivity
mode. 1999 mG full-scale with 1 mG resolution in
low-sensitivity mode.

Accuracy: 1% ±1 digit typical. The instrument is true
RMS responding, calibrated to a sine wave at 55 Hz.

DC Output (OPT D): 10 mV/mG; 2 volts FS at
200mG. Output impedance is 4kΩ.

Directionality: ± 1% (typical) for all measurement
angles.

Frequency Response: Essentially flat (± 10%)
between 40-400 Hz, with cutoff frequencies (-3 dB) of
30/600 Hz. Accuracy is better than ± 5% between 40­200 Hz for accurate measurement of the 3

rd

and 5th 60
Hz harmonic. OPTION F20 extends the -3 dB
frequencies to 20/2000 Hz.

Sensor Type: 3 x 1700 turns #38 Cu; 0.29” dia. air
core.

Environmental: Temperature Range: -10°C to +50°C
operating and -20°C to +85°C storage. Relative
Humidity: 90% at +40°C operating and 95% up to
+60°C storage.

Battery Life/Power Source: 50 hours, typical use (to

5.1V min.) using standard 9V alkaline battery
(Duracell MN1604/Eveready 522/or equivalent).

Size/Weight: Case dimensions are 5.9”H X 3.2”W x

1.2”D (OPT X01 add 0.4” to H). Weight
approximately 7 oz. (200g).

Analog Output (OPT A): Z-Axis waveform
only. 5 mV/mG; 1 volt FS at 200 mG. Output
impedance is 4 kΩ.

IV. Warranty

Sypris Test & Measurement warrants this
product against defects in material and
workmanship for a period of one year from
the date of purchase. This warranty does
not cover damage due to accidents, misuse
or tampering, nor does it cover damage
resulting from non-authorized repair. If a
malfunction or failure occurs, send the unit
insured and properly packaged to the
address listed below. Sypris Test &
Measurement will, at its option, repair or
replace the unit and return it to the
purchaser, with charges only for shipping.
This warranty is limited to the original
purchaser and is not transferable.

THE ABOVE WARRANTY IS EXPRESSLY IN
LIEU OF ALL OTHER WARRANTIES EXPRESSED
OR IMPLIED AND ALL OTHER OBLIGATIONS
AND LIABILITIES ON THE PART OF SYPRIS
TEST & MEASUREMENT AND NO PERSON
INCLUDING ANY DISTRIBUTOR, AGENT OR
REPRESENTATIVE OF SYPRIS TEST &
MEASUREMENT IS AUTHORIZED TO ASSUME
FOR SYPRIS TEST & MEASUREMENT ANY
LIABILITY ON ITS BEHALF OR ITS NAME,
EXCEPT TO REFER THE PURCHASER TO THIS
WARRANTY. THE ABOVE EXPRESS
WARRANTY IS THE ONLY WARRANTY MADE
BY SYPRIS TEST & MEASUREMENT. SYPRIS
TEST & MEASUREMENT DOES NOT MAKE AND
EXPRESSLY DISCLAIMS ANY OTHER
WARRANTIES, EITHER EXPRESSED OR
IMPLIED, INCLUDING WITHOUT LIMITING THE
FOREGOING, WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A
PARTICULAR PURPOSE OR ARISING BY
STATUTE OR OTHERWISE IN LAW OR FROM A
COURSE OF DEALING OR USAGE OF TRADE
THE EXPRESS WARRANTY STATED ABOVE IS
MADE IN LIEU OF ALL LIABILITIES FOR
DAMAGES, INCLUDING BUT NOT LIMITED TO
CONSEQUENTIAL DAMAGES, LOST PROFITS
OR THE LIKE ARISING OUT OF OR IN

CONNECTION WITH THE SALE, DELIVERY, USE
OR PERFORMANCE OF THE GOODS. IN NO
EVENT WILL SYPRIS TEST & MEASUREMENT
BE LIABLE FOR SPECIAL, INDIRECT OR
CONSEQUENTIAL DAMAGES EVEN IF SYPRIS
TEST & MEASUREMENT HAS BEEN ADVISED
OF THE POSSIBILITY OF SUCH DAMAGES.

This warranty gives you specific legal rights,
and you may also have other rights that
vary from state to state.

Answers to any questions concerning the
use of and authorized repair of this product
may be obtained by writing:

6120 Hanging Moss Road

Orlando, Florida 32807

[phone] Phone

[phone] Fax

www.sypris.com

Manual UN-01-227
Rev. C
Item No. 359194

Assembled in Mexico Printed in Mexico

ELF Meter

Model 4090

Operating Instructions

I. General Information

The Model 4090 uses three internal
orthogonal sensors to evaluate and display
a wide range of ELF magnetic fields,
independent of measurement angle. The
instrument utilizes a precision analog-to­digital converter and CMOS microprocessor
to accurately compute and display the
vector magnitude of the magnetic flux
density in milligauss. The instrument will
automatically adjust to the proper scale,
yielding a wide dynamic measurement
range of 0.1 to 1999 mG with a typical
accuracy better than 2%, sufficient for
characterizing essentially all electrical and
electronic equipment.

Under normal operating conditions the unit
will provide 50 hours of continuous use with
a standard 9v alkaline battery. A low battery
indicator will signal the user when
approximately one additional hour of
measurement time is available before the
battery needs replacing.

The instrument comes complete with a
padded, imitation leather carrying case and
a one year warranty, covering both parts
and labor. Optional features include a
switchable single-axis mode (to display the
individual vector components), analog
output, DC (recorder) output and wideband
frequency response.

Note: The term “magnetic field” is used
loosely throughout the manual. All
references to magnetic field levels in this
manual actually refer to the “magnetic flux
density”, which has (CGS) units of
milligauss (mG).

II. Operating Instructions

a. General

As a result of its inherent 3-axis method
of measurement, the Model 4090 virtually
eliminates the measure errors associated
with single-axis instruments due to
improper instrument orientation. With the
Model 4090, it is virtually impossible to
get an erroneous reading of the magnetic
field. Inexperienced and non-technical
users will benefit from the Model 4090’s
ease of use, while experienced users will
appreciate the ability to make accurate
measurements and field surveys quickly
and with full confidence.

b. Turning the Instrument On

To operate the Model 4090, first flip the
ON/OFF switch to the UP position. The
instrument will perform a self-test and
display –18.8.8 for approximately two
seconds, verifying proper operation. After
the power-on sequence has finished, the
display will indicate the magnetic reading
in mG.

c. Operation

Simply bring the instrument into the
vicinity of ELF magnetic fields and note
the magnetic field level. Upon power-on,
the meter is placed in the high-sensitivity
mode (0.1 mG resolution) and will remain
in that range until the magnetic field
exceeds 199.9 mG. At that time, the unit
is placed into the low-sensitivity mode,
where it will remain as lonl as the
magnetic field stays within the 180-1999
mG range. If the field exceeds the upper
limit of 1999 mG, the display will blank,
other than leaving a leading “1” in the
display, signifying an out-of-range
condition. If the level falls below 180 mG,
the unit will revert back to high sensitivity
mode.

The three magnetic field sensors are
located internal to the instrument just
below the LCD display, behind
“TRIAXIAL” on the front panel. The
display will indicate the magnetic field
level at that point in space. Rotation of
the instrument will not result in a
changing field indication as long as the
magnetic field is constant across the
dimensions of the internal sensors.
Some degree of directionality will be
observed in near fields, i.e. where the
magnetic field level changes rapidly over
distances comparable to the dimensions
of the instrument. In far fields, where the
magnetic field is essentially constant,
directionality of the instrument is typically
less than 1%.

d. Battery Replacement
Under normal operating conditions, the

unit will provide approximately 50 hours
of continuous use using a standard 9V
alkaline battery. When the battery level
falls below 5.4V, a low battery indication
(signaled by a minus sign) will appear.
Approximately one additional hour of
measurement time is available before
accuracy will become degraded;
however, the battery should be replaced
as soon as possible.

! Make sure the ON/OFF switch is in

the “OFF” position before replacing
the battery.

e. Dead Battery

If, after turning the instrument on, either

nothing happens or the unit behaves in
an unpredictable fashion, try replacing
the battery. If this solves the problem, it
may be that the instrument was left on

accidentally for an extended period of
time, resulting in a “dead” battery.

f. Single-Axis Mode

(Option X01). Units equipped with OPT
X01 have the ability to display the vector
components of the magnetic flux density:
Bx,By and Bz, in mG. When placed in
the single-axis mode, an arrow symbol
will appear in the upper-left area of the
LCD. It will disappear when the Model
4090 is returned to the triaxial (default)
mode. To activate the single-axis mode,
depress the push-button on the top panel
firmly until the display blanks, then
release. After blanking for approximately
one-half second, the display will indicate
the x-component of the magnetic field,
Bx. Depress the push-button a second
time until the display blanks, release and
the display will indicate By. Depress the
push-button a third time until the display
blanks, release and the display indicates
Bz. Depress the button once more and
the instrument will reset itself and enter
the triaxial mode.

Note: The x-sensor is aligned across the
meter face, from left to right. The y-sensor
alignment is across the meter face, from top
to bottom. The z-sensor alignment is
through the meter, from front to back.