ELT-400
Advanced Test Equipment Rentals
www.atecorp.com 800-404-ATEC (2832)
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Exposure Level Tester
Operating Manual
BN 2300/98.11
ELT-400
Exposure Level Tester
BN 2304/xx, Series A ...
Operating Manual
If you have any questions about this
product, please contact your local
Sales Partner.
Narda Safety Test Solutions GmbH
Sandwiesenstr. 7, 72793 Pfullingen
© 2004
Order no.: 2300/98.11
Edition : 03/04.07, A ...
Previous Edition: 02/03.08, A ...
Subject to change
Our normal guarantee and delivery
terms apply
Printed in Germany
Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
2 Safety instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
3 Preparation for use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
1.1 About this instrument. . . . . . . . . . . . . . . . . . . . . . 1-1
1.1.1 Application. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1.1.2 About this manual . . . . . . . . . . . . . . . . . . . . . . . . 1-3
2.1 Before connecting up . . . . . . . . . . . . . . . . . . . . . 2-1
2.2 Correct usage . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
2.3 AC adapter / charger unit . . . . . . . . . . . . . . . . . . 2-3
2.4 Faults and excessive stresses. . . . . . . . . . . . . . . 2-3
3.1 Unpacking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
3.1.1 Packaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
3.1.2 Checking the package contents . . . . . . . . . . . . . 3-1
3.1.3 Checking for transport damage . . . . . . . . . . . . . . 3-1
3.1.4 Recovery after storage and transport . . . . . . . . . 3-1
3.2 Power supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
3.2.1 Charging the rechargeable batteries . . . . . . . . . . 3-3
3.3 Preparing for field measurements . . . . . . . . . . . . 3-4
3.3.1 Test setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
3.3.2 Connecting / disconnecting the B field probe . . . 3-4
4 Control and display elements. . . . . . . . . . . . . . . . . . . . . . 4-1
4.1 Keypad . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
4.2 LCD display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
4.2.1 LCD display elements . . . . . . . . . . . . . . . . . . . . . 4-3
4.2.2 Display backlight . . . . . . . . . . . . . . . . . . . . . . . . . 4-5
4.3 External connectors . . . . . . . . . . . . . . . . . . . . . . 4-6
5 Operation and use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
5.1 Operating modes . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
5.1.1 Exposure STD (Shaped Time Domain) . . . . . . . . 5-2
5.1.2 Field strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3
5.2 Example applications . . . . . . . . . . . . . . . . . . . . . . 5-4
5.3 Measuring. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6
5.3.1 Switching the ELT-400 on and off . . . . . . . . . . . . . 5-6
5.3.2 Selecting the operating mode (MODE). . . . . . . . . 5-8
5.3.3 Selecting the detection mode (DETECT) . . . . . . .5-9
5.3.4 Selecting the lower frequency range limit
(LOW CUT). . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-10
5.3.5 Selecting the measurement range (RANGE) . . .5-10
5.3.6 Activating the MAX HOLD display function . . . . 5-11
5.3.7 Interpreting the measurement results. . . . . . . . . 5-12
5.4 Active probe (using the three-channel
analog output) . . . . . . . . . . . . . . . . . . . . . . . . . . 5-14
6 Maintenance and repairs . . . . . . . . . . . . . . . . . . . . . . . . . 6-1
6.1 Rechargeable and alkaline batteries . . . . . . . . . .6-1
6.1.1 Replacing the rechargeable batteries
and alkaline batteries . . . . . . . . . . . . . . . . . . . . . . 6-1
6.1.2 Disposal of alkaline and rechargeable
batteries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2
6.2 Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2
6.3 AC adapter / charger unit . . . . . . . . . . . . . . . . . . . 6-2
7 Remote control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1
7.1 Setting up the data link . . . . . . . . . . . . . . . . . . . . 7-1
7.1.1 Data cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1
7.1.2 Interface parameters . . . . . . . . . . . . . . . . . . . . . . 7-2
7.2 Fundamentals of remote control . . . . . . . . . . . . . 7-3
7.2.1 Overview of remote control commands . . . . . . . . 7-3
7.2.2 Remote control command format . . . . . . . . . . . . 7-5
7.2.3 Response value formats . . . . . . . . . . . . . . . . . . . 7-6
7.3 Remote control commands . . . . . . . . . . . . . . . . . 7-7
8 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1
8.1 Functional principle . . . . . . . . . . . . . . . . . . . . . . . 8-1
8.2 Field strength mode. . . . . . . . . . . . . . . . . . . . . . . 8-2
8.3 Exposure STD (Shaped Time Domain)
mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-5
8.4 General specifications . . . . . . . . . . . . . . . . . . . . . 8-7
8.5 Conformance labeling . . . . . . . . . . . . . . . . . . . . . 8-9
8.6 Climatic environmental conditions. . . . . . . . . . . 8-10
8.7 Dimensions and weight . . . . . . . . . . . . . . . . . . . 8-10
8.8 Ordering information . . . . . . . . . . . . . . . . . . . . . 8-11
8.9 Package contents . . . . . . . . . . . . . . . . . . . . . . . 8-11
8.10 Accessories (optional) . . . . . . . . . . . . . . . . . . . . 8-12
Annex A: Default values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1
Annex B: Exposure STD mode . . . . . . . . . . . . . . . . . . . . . . . . B-1
Annex C: Instrument function . . . . . . . . . . . . . . . . . . . . . . . . C-1
Annex D: Probe configuration / signal output . . . . . . . . . . . D-1
Index of key words
Notes:
1 Introduction
1.1 About this instrument
1.1.1 Application
Magnetic fields are present in production areas, public places and the
everyday environment. Measurements are often made in these areas to
ensure that people are not exposed to fields that could cause injuries.
Global efforts to provide effective protection have resulted in a range of
national and international guidelines and standards in recent years, which
specify reference limit values for field strengths for various frequency ranges
and signal shapes.
In practice, simple equipment must be used to determine the fields that
occur and to check that the limit values are not exceeded.
The ELT-400 is a completely new type of tester for workplace and public
area exposure to magnetic radiation. It was developed specially for the
above areas, for use by health and safety representatives in industry,
insurers, and service providers.
Production areas
The ELT-400 is particularly suitable for applications involving production
plant, including welding, smelting and heating, as well as most magnetic
stirring equipment. It can handle special requirements such as the pulsed
signals or phase control encountered in resistance welding without
problems.
Everyday environment
Magnetic fields occur everywhere in the everyday environment, being
produced by everything from power supply plant through to medical
equipment.
For example, the electromagnetic and magneto-acoustic security systems
used in department stores also operate within the frequency range of the
ELT-400.
1-1
1 Introduction ELT-400
EMC test laboratory
The ELT-400 is ideal for investigating the magnetic fields produced by
household equipment or other electrical devices. The reference test method
described in the latest product standards such as EN 50366 and
prEN 50392 is implemented precisely in this instrument.
Instrument description
The ELT-400 is extremely easy to operate using just 6 buttons and can be
used practically anywhere.
Exposure STD mode
Exposure STD mode is suitable for particularly simple and reliable
measurements on all signal shapes (single or multiple frequency fields,
pulsed fields).
The level of the magnetic field is displayed directly as a percentage of the
reference limit value, regardless of the signal shape and frequency. The
evaluation schemes specified by the relevant safety standards are
implemented in the instrument.
The numerical result therefore clearly expresses the actual situation and
indicates the available safety margin.
1-2
Field strength mode
The ELT-400 has a flat frequency response over a very wide frequency
range. Detectors for RMS and peak value measurements can be used for
broadband measurements. The results of field strength measurements are
displayed in µT or mT.
Active probe
The ELT-400 can be connected to an oscilloscope or FFT analyzer for more
in-depth analysis. The signal voltages from all three field probes (isotropic
coil configuration) are output with proper phase. The amplified voltage can
be input directly to the oscilloscope or FFT analyzer.
ELT-400 1 Introduction
1.1.2 About this manual
Typographic conventions
Some special symbols are used in certain paragraphs to make it easier to
read and understand this manual.
ª This symbol indicates a cross-reference to another chapter, section or
document.
Note: This indicates important additional information or notes
concerning special features or situations
✓ This symbol indicates a requirement that must be fulfilled before the
subsequent instructions are carried out.
⇒ This symbol indicates an action or task that must be performed.
1. A numbered list indicates a sequence of actions that must be
performed one after the other.
1-3
1 Introduction ELT-400
Notes:
1-4
2 Safety instructions
2.1 Before connecting up
This instrument was shipped in perfect condition. Please follow the
instructions below to ensure that this condition is maintained and that
operation remains safe.
2.2 Correct usage
The instrument must only be used under the conditions and for the purpose
for which it has been designed.
Strong fields
Extremely strong fields can occur close to some radiation sources.
Danger
Danger
⇒ Take care to keep within safety zones and markings.
⇒ Persons fitted with electronic implants (e.g. pacemakers) must avoid
dangerous areas.
⇒ Closely monitor the displayed measurement values as you approach any
unknown field source.
Unsuitable frequency range
The instrument’s frequency range is limited to 1 Hz and 400 kHz. Fields
outside this range will not be measured correctly. Very strong fields which
may be dangerous to persons fitted with electronic implants will not be
detected.
⇒ Use alternative suitable test equipment for field measurements outside
this frequency range.
2-1
2 Safety instructions ELT-400
Electric shock
Very high voltages can occur inside the instrument.
⇒ Make sure that the instrument or the probe does not touch any part
Danger
carrying a voltage.
⇒ Do not open the instrument.
⇒ Do not use an instrument which is opened or which is visibly damaged.
⇒ Only use the accessories supplied and designed for use with the
ELT-400.
Malfunctions
Incorrect usage, damage and impermissible repairs can adversely affect the
accuracy and function of the instrument.
Caution
⇒ Only use the instrument under the conditions and for the purpose for
which it has been designed.
⇒ Check the instrument regularly for signs of damage.
⇒ Make sure that repairs are carried out by professionals only.
Explosion
Dry batteries can explode if you attempt to recharge them. The instrument
may be damaged.
Caution
⇒ Before recharging, make sure that rechargeable batteries and not
alkaline batteries are fitted in the battery compartment.
2-2
ELT-400 2 Safety instructions
2.3 AC adapter / charger unit
Electric shock
Parts carrying dangerous voltages that may cause injury may be exposed if
the AC adapter / charger unit is damaged.
Danger
Caution
⇒ Do not use an AC adapter / charger unit that has been damaged.
Destruction
The wrong AC line voltage, condensation, excessively high or low
temperatures and poor ventilation can lead to destruction of the
AC adapter / charger unit.
⇒ Before connecting up the AC adapter / charger unit make sure that
the operating voltage of the AC adapter / charger unit is the same as the
AC line voltage.
⇒ Do not use the AC adapter / charger unit if condensation has formed on
it. If condensation is unavoidable, e.g. because the instrument has been
moved from a cold to a warm room, wait until the unit has dried off before
connecting it up.
⇒ Only use the AC adapter / charger unit indoors and at temperatures
between +5 °C and +45 °C.
2.4 Faults and excessive stresses
Take the unit out of service and secure it against unintentional operation if
safe operation is no longer possible. This will be the case, for example, if:
• the instrument shows visible signs of damage
• the instrument does not work
• the instrument has been subjected to any kind of stress that exceeds the
permitted limits.
Contact your local Service Center in such cases.
2-3
2 Safety instructions ELT-400
Notes:
2-4
3 Preparation for use
3.1 Unpacking
3.1.1 Packaging
The packaging is designed to be re-used as long as it has not been
damaged during previous transport. Please therefore keep the original
packaging and use it whenever you want to transport the instrument in
future.
3.1.2 Checking the package contents
ª Package contents: see page 8-11
3.1.3 Checking for transport damage
Check the instrument and all accessories for transport damage after you
have unpacked them. Such damage is most likely if the packaging itself has
been clearly damaged. Do not attempt to use an instrument that has been
damaged.
3.1.4 Recovery after storage and transport
Condensation may form on an instrument that has been stored or
transported at a low temperature when it is brought into a warm room. To
prevent damage, wait until all the condensation has evaporated from the
surface of the instrument before using it. The instrument must not be used
until it has reached a temperature that is within the guaranteed operating
range of -10 to +50 °C.
3-1
3 Preparation for use ELT-400
3.2 Power supply
The ELT-400 is designed to be powered from alkaline or rechargeable
batteries. The AC adapter / charger unit can also be used to provide power.
Note: The measurement characteristics of the ELT-400 may be affected
by the effect of the cable on the field when the instrument is
powered from the AC adapter / charger unit.
Operation from rechargeable batteries
The ELT-400 is powered from four 1.2 V NiMH batteries (Mignon, size AA,
IEC R 6).
The operating time from a set of fully charged batteries is about twelve
hours.
Note: The batteries are supplied pre-charged. Several charge /
discharge cycles will be needed in order to achieve their full
capacity.
Handling rechargeable batteries
• Always handle rechargeable batteries with care.
• Avoid incorrect polarity.
• Do not short-circuit the battery contacts.
• If possible, leave the ELT-400 connected to the AC adapter / charger unit
to ensure that it is always ready for use.
• Do not leave discharged batteries in the instrument for a long period of
time.
ª Charging the rechargeable batteries: see page 3-3
3-2
Operation from alkaline batteries
Four 1.5 V alkaline batteries (Mignon, Size AA, IEC LR 6) can be used in
the ELT-400 instead of rechargeable batteries.
The operating time from alkaline batteries is about 20 hours.
ª Replacing the rechargeable batteries and alkaline
batteries: see page 6-1
ELT-400 3 Preparation for use
3.2.1 Charging the rechargeable batteries
Complete recharging takes less than 2 hours.
Explosion
Alkaline batteries can explode if you attempt to recharge them.
Caution
⇒ Before you start charging the batteries, make sure that rechargeable
batteries and not alkaline batteries are fitted in the battery compartment.
Starting the charging cycle
✓ The AC line voltage matches the operating voltage of the AC adapter /
charger unit.
✓ The appropriate AC line adapter has been fitted.
1. Connect the AC adapter / charger unit to the “Charge” socket of the
ELT-400.
2. Connect the AC adapter / charger unit to the AC line supply.
• The charge cycle starts.
At least one of the four segments in the battery symbol in the LCD is
filled and flashes. Eventually all the segments will be filled as charging
proceeds.
• When the batteries are fully charged, the AC adapter / charger unit
switches to trickle charge mode automatically.
All the segments of the battery symbol in the LCD are filled and
displayed.
Note: The charge cycle is still indicated if the AC adapter / charger unit
is disconnected from the AC line after charging has started but
remains connected to the ELT-400. If charging seems to be taking
an unusually long time, check that the connection to the AC line
supply is working properly.
3-3
3 Preparation for use ELT-400
3.3 Preparing for field measurements
3.3.1 Test setup
The following are part of the complete test setup for measuring a field:
• The basic instrument
• The B field probe (cross sectional area 100 cm
The instrument uses an external isotropic magnetic field probe and is
also suitable for standards-compliant measurements in nonhomogeneous fields.
Note: Persons or objects should not come between the probe and the
radiation source during the measurement.
2
)
3.3.2 Connecting / disconnecting the B field probe
The multi-pin connector socket for the B field probe is located at the top of
the ELT-400. The field probe is secured by means of a sliding locking sleeve.
3-4
Sliding locking sleeve
Fig. 3-1 B field probe
Connecting the field probe
1. Place the probe on the basic instrument so that the red marks on the
plug and socket point in the same direction.
2. Hold the field probe by the black shaft and press it into the basic
instrument until the locking sleeve clicks into place.
The instrument detects the probe automatically.
ELT-400 3 Preparation for use
Disconnecting the field probe
⇒ Hold the field probe by the locking sleeve and pull it off the basic
instrument.
3-5
3 Preparation for use ELT-400
Notes:
3-6
4 Control and display elements
The instrument diagram in the Annex shows the positions of all control and
display elements.
4.1 Keypad
Key Function
ON/OFF
On / off key
• Starts the instrument with its default settings.
• Switches the display backlight on or off (press
briefly)
• Switches the instrument off (press for a longer
time).
MAX HOLD
Display mode selection key
• Switches the MAX HOLD display mode on or off.
• Activation of the MAX HOLD function is shown in
the display.
RANGE
Measurement range selection key
• Switches between HIGH and LOW ranges
• Selection of the HIGH setting is shown in the
display
Table 4-1 Keypad overview
4-1
4 Control and display elements ELT-400
Key Function
MODE
Operating mode selection key
• Switches between “Exposure STD” and “Field
strength” modes.
• Switches between standardized evaluation
schemes and measurement ranges.
• All evaluation schemes and measurement ranges
implemented in the instrument are shown beneath
the display. The selected setting is indicated by the
arrow symbol in the display.
DETECT
Detection mode selection key
• Switches between RMS, PEAK and STND
(Standard) detection modes.
• The selected setting is shown in the display.
LOW CUT
Lower frequency range limit selection key
• Switches the lower frequency range limit between
1 Hz, 10 Hz and 30 Hz.
• The selected setting is shown in the display.
4-2
Table 4-1 Keypad overview
ELT-400 4 Control and display elements
4.2 LCD display
4.2.1 LCD display elements
7
6
Fig. 4-1 LCD elements (example)
No. Function
1 Measured value including units
The units depend on the selected measurement mode
• %
•µT, m T
Table 4-2 LCD display elements
1
2
345
4-3
4 Control and display elements ELT-400
No. Function
2 Battery symbol consisting of a frame containing four segments.
3 Selected measurement range:
4 Selected display function:
Indicates the current charge status of the rechargeable batteries.
In operation • Outer frame displayed.
Batteries discharged • Outer frame flashes.
Batteries fully
discharged or not
fitted
Charging
(with AC adapter /
charger unit
connected)
Trickle charging
(with AC adapter /
charger unit
connected)
Note: The charge state is only indicated correctly for rechargeable
batteries that have been charged directly in the instrument.
• HIGH
• No display = LOW
• MAX = MAX HOLD activated
• No display = MAX HOLD deactivated
• Inner segments displayed to indicate the
charge level.
• All inner segments off.
• To avoid deep discharge, the ELT-400
switches off automatically after about 15
minutes.
• The battery symbol is no longer
displayed at all.
• Outer frame displayed.
• Inner segments flash to indicate the
charge level.
• Outer frame displayed.
• All inner segments displayed.
4-4
Table 4-2 LCD display elements
ELT-400 4 Control and display elements
No. Function
5 Display of selected lower frequency range limit:
• 1 Hz
• 10 Hz
• 30 Hz
6 Selected operating mode indicated by arrow symbol.
7 Display of selected detection mode:
• RMS = root mean square value.
• Stnd = automatic selection according to exposure evaluation
schemes.
• Peak = peak value.
Table 4-2 LCD display elements
4.2.2 Display backlight
Switching on the display backlight
⇒ With the instrument switched on, press the ON/OFF key briefly.
The display backlight switches on.
Switching off the display backlight
⇒ Press the ON/OFF key briefly.
The display backlight switches off.
Note: The operating time of the instrument is reduced when the display
backlight is switched on, as additional current is used. To
conserve battery power, the display backlight switches off
automatically after about 10 minutes.
4-5
4 Control and display elements ELT-400
4.3 External connectors
There are three connector sockets for external equipment on the left side of
the instrument.
Socket Function
Serial data interface
Computer (PC) connection
• 19200 baud
RS-232
Scope
• 8n1
• Handshake XON/XOFF
• For pin connections (see Fig. 7-1)
Analog signal output (active probe)
Connection to oscilloscope or analyzer
• Three channels (X-Y-Z)
• Interface cable: D-SUB15 / 3 x BNC
AC adapter / charger unit connector
• Nominal voltage: 9 V
4-6
Charge
Table 4-3 External connectors
5 Operation and use
5.1 Operating modes
Direct numerical display of:
• Safety margin compared with the exposure limit values specified in
standards (“Exposure STD” mode)
• Field strength (“Field strength” mode)
• Also for specialized analysis using an oscilloscope or FFT analyzer
(Active Probe).
Exposure STD mode
In “Exposure STD” mode, the level of the magnetic field (B field) is displayed
directly as a percentage of the reference value, regardless of the signal
shape and frequency. The user simply selects the desired standard. The
required frequency response for the limit values is emulated by means of
internal filters.
Advantages of the ELT-400:
• Instant display of current situation and safety margin without needing to
refer to the standards.
• Automatic allowance for various signal shapes as well as for pulsed
fields without need for in-depth knowledge of the field, the instrument or
the device under test.
• Continuous monitoring of the field with any change being evaluated
immediately.
• Default setting takes RMS and peak values into account simultaneously.
The appropriate detector is selected continuously and automatically,
depending on the test signal and the selected standard. The detectors
can also be selected independently to provide more information about
the signal.
Field strength mode
“Field strength” mode is useful if the field to be measured only contains a
relevant frequency component. The result is displayed in mT or µT.
5-1
5 Operation and use ELT-400
5.1.1 Exposure STD (Shaped Time Domain)
Broadband measurement with simultaneous real-time exposure
assessment
Fig. 5-1 Measurement display in “Exposure STD” mode
5-2
Measurement goal: Rapid, reliable assessment of field exposure with reference
limits from a selected standard.
Measured quantity: Field exposure.
Display: Numerical display of measurement result as a percentage
of the field strength limit value.
Special features: Different evaluation schemes (reference value curves,
exposure ranges) available depending on instrument
version.
Active probe: A frequency response weighted signal is available.
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