Atec EMR-20, EMR-30 User Manual

Radiation Meters EMR-20, EMR-30

REG.NO 572 - 02

Wandel& Goltermann Germany

EMR-20,
EMR-30

100 kHz to 3 GHz
For isotropic measurements
of electric fields

.

Non-directional (isotropic) measurement with
three-channel measurement probe

.

High dynamic range due to three-channel digital results
processing

. Optical interface for calibration and result data transfer
. Excellent measurement accuracy with automatic zeroing

even during field exposure

. Easy to use
. Shock, dust and water-resistant
. Built-in stand and tripod bush
. Calibrated

Applications

Precision measurement of electric field strength for personal
safety at work where high radiation levels are present, and for
applications involving electromagnetic compatibility (EMC),
such as:
± Service work on transmitting equipment
± Working with plastic welding machines
± Operating diathermy equipment and other medical instruments

producing short-wave radiation
± Drying equipment in the tanning and timber industries
± Field strength measurements in TEM cells and absorber

chambers

Features

The EMR-20 and EMR-30 Radiation Meters are compact, battery­powered, and easy to operate. The remote sensor is a non­directional measurement probe. The built-in optical interface
allows each of the three axes to be evaluated separately and also
allows complete remote-control of all instrument functions.

Long operating time from batteries

The EMR-20/30 is equipped with rechargeable batteries as
standard. These can be recharged while still fitted in the instru­ment, and give about 8 hours operating time. If dry batteries are
used, up to 30 hours operating time can be expected.

Calibration

Every instrument in the EMR range is calibrated for absolute level
and linearity vs. level. Typical frequency response values are also
provided (CAL factor) together with a calibration certificate. The
frequency response of every C-series instrument (EMR-20C/30C)
is measured individually, and a calibration report containing all the
measured values is included with the instrument. The instruments
can be calibrated automatically via the bi-directional optical inter­face. This allows easy calibration by the user or by recognized
national calibration laboratories, resulting in a significant reduction

Wandel &Goltermann GmbH &Co.
Elektronische Meûtechnik

Postfach 12 62
72795 Eningen, Germany

Tel. [phone]
Fax [phone]

e-mail: [e-mail]
http://www.safety-test-solutions.de

in the cost of regular re-calibration, which is recommended for all
field measuring instruments.

Limit values for common industrial and medical frequencies,
derived from the above-mentioned draft standard:

Fields of application

The diagram shows some typical applications where electro­magnetic radiation occurs or is utilized. The frequency spectrum
is normally divided into two areas:

1: Low frequencies up to about 30 kHz.

This region includes some railway system overhead power
supplies running at 16

2

/3Hz, domestic a.c. power at 50/60 Hz
and extends up to VDU workstations at 30 kHz (see EFA data
sheets).

2: High frequencies above 30 kHz.

Typical frequencies encountered here are FM radio (88 to 108
MHz), television signals (40 to 900 MHz), mobile radio (400 to
1800 MHz) and satellite communications (up to 18 GHz). Other
frequencies which are often used in industry and medicine
are 27, 433 and 2450 MHz. Knowledge of the frequency is
important when monitoring limit values for electromagnetic
fields because these limit values depend on the frequency.

AC line

voltage

Long wave

Industry

Medium

wave

Short wave

Radio waves

and medicine

VSW/VHF

Television

Cellular radio Satellite radio

UHF

Microwaves

Centimeter

waves (EHF)

Millimeter

27 MHz 433 MHz 2.45 GHz

Workplace 61.4 V/m

0.16 A/m
10 W/m

Public areas 27.5 V/m

0.07 A/m

2

2 W/m

63 V/m

0.17 A/m

2

11 W/m

28 V/m

0.08 A/m

2.2 W/m

137 V/m

0.36 A/m

2

50 W/m

61.4 V/m

0.16 A/m

2

10 W/m

Near-field and far-field

Electromagnetic fields can be split into two components: the elec­tric field E [measured in V/m] and the magnetic field H [measured
in A/m]. The E-field and H-field are strongly interdependent for the
far-field, i.e. anywhere more than a certain distance from the
source (see diagram). If, say, the H-field is measured in this
region, the magnitude of the E-field and the power density S
[W/m] can be calculated from it. In contrast, the H-field and E-field
must be measured separately in the near-field region.

waves (SHF)

Far-field

Near-field

2

2

Frequency ranges of electromagnetic radiation encountered
in everyday life.

Limit values

Work on defining legally binding limit values for electromagnetic
radiation is currently being done at national and international
levels. The limit values specified in the draft CENELEC European
standard are quoted here as an example.

E-field, workplace [V/m]

E-field,
public areas [V/m]

H-field,
public areas [A/m]0.1

Power density,
workplace [W/m

2

]

Power density,
public areas [W/m

H-field,
workplace [A/m]

2

]

Near-field and far-field definition. Measurements at a
distance d of 1 x wavelength ll (better: 3 x ll) from the source
are made under far-field conditions.

Applications and tips

± Induction heaters, RF welding equipment and erosion

machines: Electric fields are less important here, the magnetic
fields need to be monitored. Use EMR-10/EMR-10C Magnetic
Field Meter

± Radio and TV transmitters /antennas: As long as the location

is in the far-field region, an E-field sensor is preferable due to
the large bandwidth (EMR-20/EMR-30). When working close
to antennas (near-field) separate checking of the E-field and
the H-field is unavoidable (use EMR-20/EMR-30 for E-field,
EMR-10 for H-field)

± Diathermy equipment (RF equipment for medical therapy):

Very high field strengths are present at the electrodes and on
the connecting leads to the electrodes. The main component
is normally the electric field (use EMR-20/EMR-30).

± Microwave ovens: The very short wavelength means that

exposure is normally in the far-field. E-field measurements are
therefore sufficient (use EMR-20/EMR-30)

3 Limit values for electromagnetic radiation.

Further details are found in the draft European standard
CENELEC 50166-2.