Home

Narda ELT-400 Exposure Level Tester User Manual

1. Preparing for field measurements Test setup iis eee Connecting disconnecting the B field probe Keypad ik BEd KEEL TOE SES E EER Ag ie LGD displaV ti ss ER BE EE 4 dre ER DR NE LCD display elements Ee EE EE de Display backlight anana aana External connectors EE EE ee ese 5 1 5 1 1 5 1 2 5 2 5 3 5 3 1 5 3 2 5 3 3 5 3 4 Operation and use 000 ec eee eee eee 5 1 Operating modes 00000 ee aeeee 5 1 Exposure STD Shaped Time Domain 5 2 Field strength 2 2 0 0 e ee eee eee 5 3 Example applications 044 5 4 Measuring 0c eee eee 5 6 Switching the ELT 400 on and off 5 6 Selecting the operating mode MODE 5 8 Selecting the detection mode DETECT 5 9 Selecting the lower frequency range limit LOW CUT as ects Ede eeu ee tt Menara ald 5 10 5 3 5 5 3 6 5 3 7 5 4 Selecting the measurement range RANGE 5 10 Activating the MAX HOLD display function 5 11 Interpreting the measurement results 5 12 Active probe using the three channel analog output 0000020 eee 5 14 Maintenance and repairs 00 2e ER RR ER 6 1 6 1 1 6 1 2 6 2 6 3 Rechargeable and alkaline batteries Replacing the rechargeable batteries and alkaline batteries 00 Disposal of alkaline and rechargeable batteiies ea SEE cea gee as Lead
2. 2 Safety instructions 2 3 AC adapter charger unit A Danger N Caution Electric shock Parts carrying dangerous voltages that may cause injury may be exposed if the AC adapter charger unit is damaged 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 gt 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 e the instrument shows visible signs of damage e 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
3. 4 1 4 Control and display elements ELT 400 4 2 Function MODE Operating mode selection key e Switches between Exposure STD and Field strength modes e Switches between standardized evaluation schemes and measurement ranges e 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 e Switches between RMS PEAK and STND Standard detection modes e The selected setting is shown in the display LOW CUT Lower frequency range limit selection key e Switches the lower frequency range limit between 1 Hz 10 Hz and 30 Hz e The selected setting is shown in the display Table 4 1 Keypad overview ELT 400 4 Control and display elements 4 2 LCD display 4 2 1 LCD display elements 7 1 2 6 ICNIRP ICNIRP 1998 1998 320 pT 80 mT Gen Pub aml 5 4 3 Fig 4 1 LCD elements example No Function 1 Measured value including units The units depend on the selected measurement mode e e uT mT Table 4 2 LCD display elements 4 3 4 Control and display elements ELT 400 4 4 No Function 2 Battery symbol consisting of a frame containing four segments Indicates the current charge status of the rechargeable batteries In operation e Outer frame displayed e
4. 0 Field strength mode 1 Exposure STD mode Table 7 4 Operating mode characterization text Explanation Additional information e End value RMS value if param 0 e Standard s name and exposure range if param 1 Table 7 5 Additional information Note The length of lt text gt is limited to 30 characters ELT 400 7 Remote control SET DETECTOR lt SP gt lt param gt CR lt LF gt SET DETECTOR CR lt LF gt Response lt param gt lt CR gt lt LF gt Meaning Selects the detection mode param Explanation RMS The RMS value measured using the selected operating mode will be output PEAK The peak value measured using the selected operating mode will be output STND In Exposure STD mode only The detection mode is selected automatically according to the selected standard Table 7 6 Detection mode selection settings 7 9 7 Remote control ELT 400 SET LOW_CUT lt SP gt lt param gt CR lt LF gt SET LOW_CUT CR lt LF gt Response lt param gt lt CR gt lt LF gt Meaning Sets the lower frequency range limit param Explanation 1 Defines 1 Hz as the lower frequency range limit 10 Defines 10 Hz as the lower frequency range limit 30 Defines 30 Hz as the lower frequency range limit Table 7 7 Lower frequency range limit settings 7 10 ELT 400 7 Remote control SET MAX_HOLD lt SP
5. The amplified voltage can be input directly to the oscilloscope or FFT analyzer 1 2 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 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 J 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 A Danger Danger A 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 gt Take care to keep within safety zones and markings gt Persons fitted with electronic implants e g pacemakers must avoid dangerous areas Closely monitor the displayed measurement values
6. Inner segments displayed to indicate the charge level Batteries discharged e Outer frame flashes e Allinner segments off e To avoid deep discharge the ELT 400 switches off automatically after about 15 minutes Batteries fully e The battery symbol is no longer discharged or not displayed at all fitted Charging e Outer frame displayed with AC adapter e Inner segments flash to indicate the charger unit charge level connected Trickle charging e Outer frame displayed with AC adapter e Allinner segments displayed charger unit connected Note The charge state is only indicated correctly for rechargeable batteries that have been charged directly in the instrument 3 Selected measurement range e HIGH e No display LOW 4 Selected display function e MAX MAX HOLD activated e No display MAX HOLD deactivated Table 4 2 LCD display elements ELT 400 4 Control and display elements No Function Display of selected lower frequency range limit e 1Hz e 10Hz e 30 Hz Selected operating mode indicated by arrow symbol Display of selected detection mode e RMS root mean square value e Stnd automatic selection according to exposure evaluation schemes e 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 Swit
7. You can also select RMS and PEAK detection if required RMS root mean square value The RMS value resulting from the isotropic measurement is derived from the RMS values for the three individual measurement axes PEAK peak value The peak value of the isotropic measurement is derived from the peak value of the field vector The phase in the three individual measurement axes is taken into account Table 5 2 Available detection modes depending on the selected operating mode Press the DETECT key until the required detection mode is shown in the display Note The selected detection mode is applied immediately The measurement value is valid as soon as the switch over occurs 5 9 5 Operation and use ELT 400 5 3 4 Selecting the lower frequency range limit LOW CUT The default measurement range setting is limited to 30 Hz to 400 KHz The lower freguency range limit can be extended down to 1 Hz or 10 Hz Press the LOW CUT key until the required value for the lower frequency range limit is shown in the display Note The 1 Hz and 10 Hz settings should only be selected when this is necessary for the measurement application Operating modes see page 5 1 The effect of e g the earth s magnetic field is clearly discernible when the instrument is moved if one of these settings is made A tripod can be used to prevent these effects Note The measurement display will fluctuate whenever the sett
8. 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 gt Use alternative suitable test equipment for field measurements outside this frequency range 2 1 2 Safety instructions ELT 400 A Danger 2 2 A Caution A Caution Electric shock Very high voltages can occur inside the instrument gt Make sure that the instrument or the probe does not touch any part carrying a voltage gt 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 gt 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 gt 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 gt Before recharging make sure that rechargeable batteries and not alkaline batteries are fitted in the battery compartment ELT 400
9. circuit diagram C 1 Annex C Instrument function ELT 400 C 2 Transfer function The transfer function defines the intended frequency response of the measuring instrument and includes the field probe measuring coils The transfer functions for the various operating modes differ significantly from each other Operating mode Transfer function EXPOSURE STD e Takes the frequency response of the limit value curve and the selected exposure range into account e Attenuation occurs at the frequency range limits Band limits see page C 4 FIELD STRENGTH e ls independent of frequency flat over a wide range e Attenuation occurs at the frequency range limits Band limits see page C 4 Detection mode Detector The ELT 400 simultaneously measures the RMS value and the peak value of the magnetic field Both values are available immediately after the detection mode is switched The measured values are continuously every 250 ms updated and displayed RMS value The RMS value B of the magnetic flux density is calculated from the RMS values for each of the three measurement axes i e By to Bz The RMS value is always independent of the time phases of the field components The averaging integration time for the RMS calculation is fixed at 1 second to conform with the relevant personal safety standards ELT 400 Annex C Instrument function Peak value The peak value B of the magnetic flux density is calculat
10. 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 EL
11. range limit settings If the measurement is to be referred to the spatial axes the probe must be aligned to correspond Annex D Probe configuration signal output see page D 1 The analog output can be used in both modes Exposure STD and Field Strength The maximum output voltage of 800 mV RMS equals in each case the scale end value of the selected measurement range The impedance of the output is 50 Ohm A minimum load impedance of 10 kOhm is required Slight DC offsets can be present at the output We recommend that you measure with the oscilloscope or spectrum analyzer in AC mode Note the following depending on the measurement mode Field Strength mode The output voltages at the X Y and Z outputs correspond in each case to the measured field strength magnitude and phase Exposure STD mode The magnitude and phase of the output voltage vary relative to the field strength due to the transfer function in Exposure STD mode the phase relationship between the three channels X Y Z is unaffected ELT 400 5 Operation and use Example Sinusoidal signal in range 10 500 Hz measured in Exposure STD mode Analog output voltages on channels X Y and Z are phase shifted relative to the measured field strength by approx 90 due to the differentiating transfer function in Exposure STD mode The output signal is the derivative vs time of the field strength 5 Operation and use ELT 400 Notes 5 16 6
12. unit 2 3 6 2 8 9 Accessories 8 12 Active probe 1 2 5 14 Alkaline batteries 6 1 Application 1 1 EMC test laboratory 1 2 Everyday environment 1 1 Production areas 1 1 B field probe 3 4 Connecting 3 4 Disconnecting 3 4 Basic instrument keypad 4 1 Batteries 4 4 8 8 Charging 3 3 Block circuit diagram C 1 Broadband measurements 1 2 C Calibration interval 8 9 Charge 4 6 Cleaning 6 2 Climatic parameters 8 10 Condensation 2 3 Conformance labeling 8 9 Connecting up 2 1 Correct usage 2 1 D Damage level 8 3 Default values A 1 Detect 4 2 5 9 Detection mode 4 5 5 9 C 2 Detector C 2 Dimensions 8 10 Direction of data flow 7 1 Display backlight 4 5 Display function 4 4 Display mode 5 11 E EMC test laboratory 1 2 Environment classes 8 10 Evaluation schemes 1 2 4 2 5 2 5 12 Exposure 1 2 Exposure STD 1 2 5 1 5 2 8 5 C 2 Dynamic range 8 6 Frequency range 8 5 Measurement range 8 6 Measurement value collection 8 6 F FFT analyzer 1 2 5 14 Fiber optic cable 7 1 Field strength 1 2 5 1 5 3 C 2 Dynamic range 8 2 Measurement range 8 2 Measurement uncertainty 8 4 Measurement value collection 8 3 Frequency response C 2 Function test 5 6 Functional principle 8 1 C 1 Instrument Connecting to the measurement computer data cable 7 2 Instrument description 1 2 Instrument function C 1 L Low Cut 4 2 5 10 Lower frequency range limit 4 5 Lower measurement range limit 5 12 Max Ho
13. 4 ELT 400 Annex C Instrument function Settling time The variation with time of the field under investigation is sampled at intervals of about 1 us This means that the internal signal voltages reflect any changes in the field immediately The peak value is measured at the same high sampling rate The displayed measurement value is updated every 250 ms The RMS value is always determined by integrating averaging the variation in the field Some personal safety standards specify an integration averaging time of 1 second for the frequency range in question The ELT 400 takes this into account The numerical result display will therefore require a settling time of 1 second if there is a sudden increase in field strength Short term changes in the field e g pulses lead as intended to a smaller RMS value depending on the pulse duration The display is updated every 250 ms C 5 Annex C Instrument function ELT 400 Overload monitoring The measurement signals of all three measurement channels X Y Z are monitored separately The overload indicator is displayed if an overload occurs in at least one of the channels id ICNIRP ICNIRP 1998 1998 320 uT 80 mT Gen Pub Occ Fig C 4 Overload indicator The overload indicator is displayed as long as the result is not valid i e normally for at least 1 second standardized averaging time In MAX HOLD display mode the overload indicator can only be cleared by swit
14. 400 SYST ERR CR lt LF gt Response lt param gt lt CR gt lt LF gt Meaning Queries the error status resulting from the last command used The response value indicates the correct interpretation of the previously sent command or the instrument status param Explanation 0 No error 109 Incomplete parameter 110 Unknown command 224 Parameter value outside range limits 290 Incorrect probe type connected 300 Instrument is not yet in measurement phase 310 No probe connected 400 No data ready Table 7 14 SYST ERR command response values 7 20 ELT 400 7 Remote control Data transfer protocol SYST XONXOFF lt SP gt lt param gt CR lt LF gt SYST XONXOFF CR lt LF gt Response lt param gt lt CR gt lt LF gt Meaning Selects the software handshake param Explanation ON Activates XON XOFF software handshake OFF Deactivates XON XOFF software handshake Setting the default values SYST DEFAULTS CR lt LF gt Meaning Sets the instrument settings to their default factory values Annex A Default values The instrument information and the current measurement units are also returned Example NARDA STS ELT 400 BN2300 01 A 0001 V1 00 7 21 7 Remote control ELT 400 Notes 7 22 8 Specifications The specifications are valid for the following conditions and settings unless otherwise stated Ambi
15. BN 2300 98 11 ELT 400 Exposure Level Tester Operating Manual narda Safety Test Solutions an Communications Company ELT 400 Exposure Level Tester BN 2304 xx Series A Operating Manual N narda Safety Test Solutions an B Communications Company If you have any guestions about this product please contact your local Sales Partner RAECD Revels 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 Introduci n s ae ss RM EE ge ee a thaw EE EE 1 1 About this instrument EE Se 1 1 1 Application 0 0 0 0 cee 1 1 2 About this manual 00005 Safety instructions 2 1 2 2 2 3 2 4 Preparation for use 3 1 3 1 1 3 1 2 3 1 3 3 1 4 3 2 3 2 1 3 3 3 3 1 3 3 2 Conirol and display elements 4 1 4 2 4 2 1 4 2 2 4 3 Before connecting UP 200 00e Correct usage cee AC adapter charger unit Faults and excessive stresseS Unpaeklng sites REM Re SR diet PAR ais Packaging EE eee eee ee Checking the package contents Checking for transport damage Recovery after storage and transport Power supply 0 00 e eee eee ee eee Charging the rechargeable batteries
16. Hz 30 Hz to 400 kHz Frequency response As per selected standard emulated by 1st order filters at the specified corner frequencies Additional attenuation occurs at the selected band limits see figure C 2 see figure C 3 8 5 8 Specifications ELT 400 8 6 Measurement range dynamic range Nominal measurement range The fixed measurement range is nominally 100 of the selected limit value curve Operating mode ICNIRP BGV B11 prEN 50366 Range Low High Low High Overload limit 160 1600 160 1600 Nominal measurement 10 100 10 100 range Intrinsic noise 1 3 6 0 4 1 6 approximate 1 The frequency dependent damage level should also be taken into account see Fig 8 1 Display resolution Range Low 0 001 Measurement value collection Sampling frequency 1 048576 MHz Measurement interval measurement rate 250 ms 4 per second RMS RMS value detector Continuous integration over 4 intervals sliding evaluation window 1 sec Peak Peak value detector Maximum value in each interval true phase Stnd Automatic detector Continuous calculation from RMS and or peak depending on the standard selected Measurement axes evaluated X Y and Z isotropic combined for resulting exposure level ELT 400 8 Specifications Result displ
17. Maintenance and repairs 6 1 Rechargeable and alkaline batteries 6 1 1 Caution A Replacing the rechargeable batteries and alkaline batteries vy The ELT 400 is switched off v The ELT 400 is disconnected from the AC adapter charger unit Changing the rechargeable or alkaline batteries 1 Remove the probe 2 Starting from the lower side of the instrument slide off the rubber cover 3 Push down the locking button on the back of the instrument and remove the battery compartment lid The battery compartment is now accessible 4 Insert the new alkaline or rechargeable batteries Make sure that you insert them correctly positive and negative poles are marked in the instrument NS Fig 6 1 Polarity markings in the instrument battery compartment 5 Replace the battery compartment lid and close it 6 Starting from the top side of the instrument slide the rubber cover back onto the instrument 7 Plug in the probe The instrument is ready to use again Destruction of instrument The instrument may be damaged if the batteries are inserted incorrectly gt Before charging the batteries make sure they are inserted correctly according to the polarity markings inside the battery compartment 6 Maintenance and repairs ELT 400 6 1 2 Disposal of alkaline and rechargeable batteries The instrument contains NiMH batteries or alkaline batteries Note Do not put rechargeable or alkaline ba
18. T 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 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 uT 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
19. ampling frequency 1 048576 MHz Measurement interval 250 ms measurement rate 4 per second RMS RMS value detector Continuous integration over 4 intervals sliding evaluation window 1 sec Peak Peak value detector Maximum value in each interval proper phase Measurement axes evaluated X Y and Z isotropic combined for resulting flux density 8 3 8 Specifications ELT 400 Measurement uncertainty Measurement uncertainty 4 50 Hz to 120 kHz Note The following influence quantities must also be taken into account e Frequency response at the selected band limits 10 Hz 30 Hz 400 kHz 3 dB 1 dB 1 Hz 3 dB 2 dB e Sufficient signal to noise ratio Result display Result display Instantaneous value or maximum value MAX selectable HOLD Display type Digital Digital display resolution 4 digits Refresh rate 4 times per second Units selectable mT or uT 8 4 ELT 400 8 Specifications 8 3 Exposure STD Shaped Time Domain mode Brief description e Measurement of magnetic flux density taking the limit value characteristic of the selected standard into account e RMS and peak values are measured and calculated simultaneously e Display of magnetic flux density as a percentage A display of 100 indicates that the limit value has been reached Frequency range Frequency range 3 dB selectable 1 Hz to 400 kHz 10 Hz to 400 k
20. aram gt CR lt LF gt see page 7 17 CALC OVLD lt SP gt lt param gt CR lt LF gt see page 7 18 GET MODE_INFO lt SP gt lt STD gt lt name gt CR lt LF gt see page 7 8 MEAS CR lt LF gt see page 7 14 SEN TYPE CR lt LF gt see page 7 7 SET DETECTOR lt SP gt lt param gt CR lt LF gt see page 7 9 SET LOW_CUT lt SP gt lt param gt CR lt LF gt see page 7 10 SET MAX_HOLD lt SP gt lt param gt CR lt LF gt see page 7 11 SET MODE lt SP gt lt param gt CR lt LF gt see page 7 12 SET RANGE lt SP gt lt param gt CR lt LF gt see page 7 13 Table 7 2 Remote control commands in the measurement phase 7 4 ELT 400 7 Remote control 7 2 2 Remote control command format The following conventions are used to describe the remote control commands Character Meaning Instrument parameter measurement value query param Instrument status transfer parameter Optional information is given in square brackets lt gt Mandatory information is given in pointed lt brackets gt SP Space ASCII decimal character 32 CR Carriage Return ASCII decimal character 13 LF Line Feed decimal character 10 Separates alternative entries Table 7 3 Remote control command conventions Note The remote control commands do not distinguish between upper and lower case letters The remote control command will be ignored if the value of the transfer parameter param is outside
21. ason the result displayed in Exposure STD mode is not the measured field strength but rather the exposure level in percent as already calculated There is no need to find out the reference value from the standard and calculate the exposure level Derivation of exposure calculation in Exposure STD mode The reference values are specified in the form of tables or curves in the various standards This information can be split into different components for the purposes of further discussion e Limit value curve frequency dependency e Limit value curve field strength dependency exposure range The function of Exposure STD mode is illustrated by taking these items separately B 1 Annex B Exposure STD mode ELT 400 B 2 Limit value curve freguency dependency The freguency response describes the degree to which the field strength at a given freguency f1 may differ from that at another given freguency f2 for the limit value to be achieved in both cases The limit value curve can thus also be interpreted as an attenuation curve In Exposure STD mode this attenuation curve is simulated by several first order filters The relevant corner frequency is taken from the standard The abrupt transitions at the corner frequencies are smoothed by the filters leading to discrepancies of up to 3 dB These deviations are accepted by ICNIRP Guidance on Determining Compliance of Exposure to Pulsed and Complex Non Sinusoidal W
22. aveforms below 100kHz Health Physics Vol 84 No 3 2003 since they correspond to the biological effect of the field on humans The filters in the ELT 400 are switched to correspond with the relevant standard as well as to the selected exposure range Example Limit values for 50 Hz and 150 Hz are taken from ICNIRP 1998 The corresponding reference values are 100 uT and 33 3 uT i e the permitted values differ by a factor of 3 If the field at 50 Hz is attenuated by the filter during the measurement by a factor of 3 compared to the field at 150 Hz both displayed values will be the same when the field strength reference value is reached Frequency measurement is not required since the filter converts the frequency information into the appropriate attenuation This also avoids the uncertainty in measuring the frequency of a signal of unknown shape e g harmonics interference frequencies etc Note This method has long been used with noise level meters Limit value curve field strength dependency Since the frequency dependency of the reference values is fixed by the filters only the level dependency for the selected exposure range needs to be scaled appropriately The instrument must indicate the value 100 when the limit value is reached This scaling is done during manufacture of the ELT 400 The display is adjusted accordingly at any given frequency Switching the exposure level e g from General Public to Occupati
23. ay Result display Instantaneous value or maximum value MAX selectable HOLD Display type Digital Digital display resolution 4 digits Refresh rate 4 times per second Units Percent 8 4 General specifications Display type and warning features Display type LCD display with backlight Refresh rate 4 times per second Remote control interface serial Type RS 232 Connection 3 wire TxD RxD Gnd Bits per second 19200 Data bits 8 Parity None Stop bits 1 Handshake XON XOFF 8 7 8 Specifications ELT 400 Analog signal output Scope Output signal X Y Z isotropic Three separate channels Output voltage for nominal 50 mV RMS measurement range Output impedance 50 ohm Load impedance 210 kohm Channel configuration See Annex D Probe configuration 1 See under Measurement range for the selected operating mode Measurement probe Effective coil cross sectional area 100 cm Construction features 3 coils arranged orthogonally common center point Orientation See Annex D Probe configuration External dimensions Diameter 125 mm Length approximately 300 mm Power supply Battery operation Rechargeable NiMH batteries replaceable 4 x Mignon size AA IEC R6 e g Sanyo HR 3 U rechargeable batteries no measurement operations Operating time f
24. changed DETECT Unchanged Variable Unchanged Unchanged detection mode MAX HOLD OFF OFF OFF OFF display mode LOW CUT lower Unchanged Unchanged As set Unchanged frequency range limit Measured values display status of the following instrument functions e RMS PEAK STND Cleared Cleared Cleared Cleared e MAX HOLD Cleared Cleared Cleared Cleared e OVLD Cleared Cleared Cleared Cleared CALC BAT Unchanged Unchanged Unchanged Unchanged CALC OVL Unchanged Unchanged Unchanged Unchanged SYST XONXOFF Unchanged Unchanged Unchanged Unchanged A 2 1 Depends on the selected operating mode RMS in Field strength mode STND in Exposure STD mode Table A 2 Status of major parameters after various actions Annex B Exposure STD mode Technical background Health and safety standards prescribe various methods for determining field exposure where the reference values stated in the standard are compared with the measured values Bmeas Bref In calculating the exposure this means Bmeas Bref s1 100 The result of the exposure calculation is always expressed as a percentage of the reference value If the measured value is exactly the same as the reference value the result is 100 Smaller values directly indicate that the limit has not been exceeded lt is therefore not necessary to express the result in units of field strength mT to assess the exposure level For this re
25. ching off the MAX HOLD function Selecting the display mode see page 5 11 Annex D Probe configuration signal output The internal sensor coils are arranged orthogonally The configuration of the coils is not immediately visible externally If you require the result display to be referred to the spatial axes of the room in which the measurement is made the probe coils must be configured so that they match the spatial axes of the room Use the diagram below to position the probe correctly Top view daa Side view Fig D 1 Probe configuration Positioning the probe gt Tilt the ELT 400 up by exactly 35 3 from the horizontal and secure it in this position Top view The effective coil cross sectional areas for the X and Z coils are perpendicular They are each oriented at 45 to the center axis Side view The Y axis is perpendicular with the coil cross sectional area horizontal Annex D Probe configuration signal output ELT 400 Connecting cable The following connections are provided if the analog interface cable BN 2260 90 80 is used Koax plug e Red X axis e Green Y axis e Blue Z axis DB9 plug 1 X Axis 2 Y Axis 3 Z Axis 6 GND 7 GND 8 GND plug housing GND Fig D 2 DB9 plug connections ELT 400 B field probe connector v KNP ICNIRP gt EE Charge Notes Index of key words A AC adapter charger
26. ching 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 4 6 External connectors There are three connector sockets for external equipment on the left side of the instrument Socket Function RS 232 Serial data interface Computer PC connection 19200 baud 8n1 Handshake XON XOFF For pin connections see Fig 7 1 Analog signal output active probe Connection to oscilloscope or analyzer e Three channels X Y Z e Interface cable D SUB15 3 x BNC Charge AC adapter charger unit connector e Nominal voltage 9 V 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
27. cket 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 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 3 4 ELT 400 3 Preparation for use Disconnecting the field probe gt Hold the field probe by the locking sleeve and pull it off the basic instrument 3 Preparation for use ELT 400 Notes 3 6 4 Control and display elements 4 1 The instrument diagram in the Annex shows the positions of all control and display elements Keypad Key Function ON OFF On off key e Starts the instrument with its default settings e Switches the display backlight on or off press briefly e Switches the instrument off press for a longer time MAX HOLD Display mode selection key e Switches the MAX HOLD display mode on or off e Activation of the MAX HOLD function is shown in lt the display RANGE Measurement range selection key e Switches between HIGH and LOW ranges e Selection of the HIGH setting is shown in the display Table 4 1 Keypad overview
28. d 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 e Do not leave discharged batteries in the instrument for a long period of time Charging the rechargeable batteries see page 3 3 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 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 N Alkaline batteries can explode if you attempt to recharge them gt Before you start charging the batteries make sure that rechargeable Caution batteries and not alkaline batteries are fitted in the battery compartment Starting the charging cycle J The AC line voltage matches the operating voltage of the AC adapter cha
29. densation allowed 8 7 Dimensions and weight Dimensions w x h x d 180 x 100 x 55 mm without probe Weight incl batteries and probe approximately 770 g 8 10 ELT 400 8 Specifications 8 8 Ordering information Built in operating modes MODE Order number e EXPOSURE STD ICNIRP gen pub BN 2304 101 e EXPOSURE STD ICNIRP occ e FIELDSTRENGTH 320 uT e FIELDSTRENGTH 80 mT EXPOSURE STD BGV B11 EXP2 BN 2304 102 EXPOSURE STD BGV B11 EXP1 EXPOSURE STD BGV B11 2H D FIELDSTRENGTH 8 mT prEN 50366 BN 2304 103 EXPOSURE STD ICNIRP occ FIELDSTRENGTH 320 uT FIELDSTRENGTH 80 mT 8 9 Package contents Basic instrument BN 2304 xx B field probe 100 cm BN 2300 90 10 AC adapter charger unit 9 V BN 2259 92 02 Operating and programming manual Calibration certificate 4 rechargeable batteries 8 11 8 Specifications ELT 400 8 10 Accessories optional 8 12 Extension cable probe instrument 2300 90 30 length 1 m RS 232 interface cable length 2 m with 2260 90 51 jack plug DB9 plug Analog interface cable D Sub 15 3 x BNC 2260 90 80 length 3 m Tripod non conductive height 1 65 m 2244 90 31 Tripod extension non conductive height 0 5 m 2244 90 45 Transport bag 2245 90 07 Annex A Default values The table below lists the default values ex works settings of th
30. e ELT 400 e when the instrument is switched on e after the remote control command SYST DEFAULTS has been executed detection mode Parameter Default setting RANGE HIGH MODE Depends on the instrument version selected built in operating modes e Default is the operating mode shown farthest to the left on the basic instrument DETECT Depends on the mode selected e RMS if a field strength mode is preset e STND if an Exposure STD mode is preset MAX HOLD OFF current measurement value is displayed display function LOW CUT 30 Hz lower frequency range limit Status display e MAX HOLD Cleared e OVLD Cleared CALC BAT OFF battery status not returned at the end of a result transfer CALC OVLD OFF overload status not returned at the end of a result transfer SYST KLOCK OFF no keypad lock SYST XONXOFF ON data transfer protocol activated Table A 1 Default values The following table shows the status of the major parameters after various actions A 1 Annex A Default values ELT 400 Parameter Status of parameter after action Change of Change of Change of Change of measuring operating lower frequency probe range mode range limit RANGE MODE LOW CUT Status of parameter after remote control command SET SET SET RANGE MODE LOW_CUT RANGE As set Unchanged Unchanged Unchanged MODE Unchanged As set Unchanged Un
31. e page 7 17 Remote control command CALC OVLD see page 7 18 7 15 7 Remote control ELT 400 7 16 SYST KLOC lt SP gt lt param gt CR lt LF gt SYST KLOC CR lt LF gt Response lt param gt lt CR gt lt LF gt Meaning Locks unlocks the keypad of the basic instrument param Explanation ON Locks the basic instrument keypad The instrument does not respond if any of the operating keys are pressed in this status OFF Unlocks the instrument keypad Table 7 11 Basic instrument keypad lock settings Note The basic instrument can still be switched off using the ON OFF key when the keypad is locked The keypad is unlocked when you switch the basic instrument on again ELT 400 7 Remote control Instrument status query CALC BAT lt SP gt lt param gt CR lt LF gt CALC BAT CR lt LF gt Response lt param gt lt CR gt lt LF gt Meaning Activates deactivates battery status information param Explanation ON Battery status response with every measured value transfer OFF No battery status response Table 7 12 Battery status response settings The battery status is appended to the response values for a field measurement Remote control command MEAS see page 7 14 7 17 7 Remote control ELT 400 7 18 CALC OVLD lt SP gt lt param gt CR lt LF gt CALC OVLD CR lt LF gt Response lt param gt lt CR gt lt LF gt Meanin
32. ed ad Cleaning 0 0c eee eee AC adapter charger unit 7 Remote control iss ss eee eee eee 7 1 7 1 Setting up the data link ie EE ie 7 1 7 1 1 Data cable 200 EE Ee ee eee 7 1 7 1 2 Interface parameters EE EE ee eee 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 04 7 6 7 3 Remote control commands 7 7 8 Specifications sai sae kak RE ee 8 1 8 1 Functional principle EE EE EE Ee 8 1 8 2 Field strength mode ee EE EE Ee 8 2 8 3 Exposure STD Shaped Time Domain MOCO EE EA RE TE OE EE 8 5 8 4 General specifications EE EE ie 8 7 8 5 Conformance labeling AE EE de 8 9 8 6 Climatic environmental conditions 8 10 8 7 Dimensions and weight 8 10 8 8 Ordering information 45 8 11 8 9 Package contents 0 005 8 11 8 10 Accessories optional 0 8 12 Annex A Default values 0000 e eee eee eee A 1 Annex B Exposure STD mode s a es se sae ese B 1 Annex C Instrument function sae ka Ek RR Ra RR Re C 1 Annex D Probe configuration signal output D 1 Index of key words Notes 1 1 1 1 1 1 Introduction About this instrument Application Magnetic
33. ed from the variation with time B t through B t of the magnetic flux density in each of the three measurement axes B van BY By t s70 The peak value always depends on the phases of the measured field components For this reason vectorial addition is used Stnd Standard The results in Exposure STD mode are expressed as a percentage of the limit value The detection modes to be used for the measurement are specified sometimes within separate clauses by the relevant personal safety standards They are of decisive importance in ensuring that the results are measured correctly regardless of the signal shape multiple or single frequency fields pulsed fields There are some standards where both the RMS value and the peak value must be taken into account at the same time in order to determine exposure The ELT 400 compares both measurement results continuously and displays the relevant measured value applying the prescribed weighting factor Vmax Where necessary C 3 Annex C Instrument function ELT 400 Band limits The signal is attenuated according to the following function at the upper and lower limits of the frequency range Gain dB Frequency Hz Fig C 2 Lower band limits LOW CUT 1 Hz 10 Hz and 30 Hz Gain de Frequency KHz Fig C 3 Upper band limit C
34. ent temperature 23 C 3 C Relative humidity 40 60 Sine wave signal CW Root mean square value RMS Lower frequency range limit 30 Hz Operation from rechargeable or alkaline batteries Note The use of connecting cables for the external connectors RS 232 Scope and Charge can alter the specifications and the measured value that is displayed If you notice any such changes experiment by moving the position of the cable in the field until the coupling effects are minimized 8 1 Functional principle The voltage induced in a measurement coil probe is evaluated in order to measure the magnetic flux density The signal voltage is digitized and evaluated by a digital signal processor DSP The DSP simulates the selected filter characteristics and calculates the flux density resulting from the voltage The orthogonal configuration of the three measurement coils allows the field to be measured isotropically i e independent of spatial direction The three channels are output with their correct phases 8 Specifications ELT 400 8 2 8 2 Field strength mode Brief description e Measurement of magnetic flux density based on a broadband evaluation of the measurement signal e Display of measurement result in units of mT or uT Frequency range Bandwidth 3 dB 1 Hz to 400 kHz 10 Hz to 400 kHz 30 Hz to 400 kHz selectable Frequency response Flat response attenuation occurs at the selected band
35. essary Table 5 1 Example applications and instrument settings 5 5 5 Operation and use ELT 400 5 3 Measuring 5 3 1 Switching the ELT 400 on and off Switching the ELT 400 on y You have made sure of the power supply Press the ON OFF key briefly The basic instrument switches on The function test runs Function test The function test checks the internal memory display signal processor and internal signal paths e During the function test all elements of the display and the display backlight are switched on for 0 5 seconds the firmware version is displayed for about 2 seconds Fig 5 3 Test display ELT 400 5 Operation and use When the function test is successfully completed the measurement display appears You can now start making measurements ICNIRP ICNIRP 1998 1998 320 uT 80 mT Gen Pub Occ Fig 5 4 Measurement display Switching off the ELT 400 Press and hold down the ON OFF key for about 3 seconds The basic instrument switches off Possible faults No display after switch on The rechargeable batteries or alkaline batteries are completely discharged gt Recharge the batteries or replace the alkaline batteries Charging the rechargeable batteries see page 3 3 Replacing the rechargeable batteries and alkaline batteries see page 6 1 One of the following error messages appears after switching on F200 F210 F240 F250 F260 F280 An instrument error
36. g Sets whether or not overload status information is returned at the end of a result param Explanation ON Overload status indicator response every time a measured value is transferred OFF No overload status indicator response Table 7 13 Overload status indicator response settings The overload status indication is appended to the response values for a field measurement Remote control command MEAS see page 7 14 MEAS BAT CR lt LF gt Response lt param gt lt CR gt lt LF gt Meaning Queries the current battery voltage measured value units separated by a comma Example 4987 mV ELT 400 7 Remote control SYST BAT CR lt LF gt Response lt param gt lt CR gt lt LF gt Meaning Queries the battery charge status param Explanation BAT_OK Battery is charged BAT_LOW Battery is discharged Note If you regularly query the charge status the instrument will continue to operate for about 15 minutes after the first appearance of the BAT LOW message The instrument will then switch off automatically IDN CR lt LF gt Response Returns the following information separated by commas Example NARDA STS ELT 400 BN 2300 01 A 0001 V1 00 Manufacturer Instrument name Article number Serial number Version number Note The text length for each item of information is limited to 12 characters 7 19 7 Remote control ELT
37. gt lt param gt CR lt LF gt SET MAX_HOLD CR lt LF gt Response lt param gt lt CR gt lt LF gt Meaning Activates deactivates the MAX HOLD display function param Explanation ON Activate MAX HOLD display function e The highest value measured since the function was activated is output instead of the current measurement value e The status of the overload display takes into account the instrument status since the function was activated Remote control command CALC OVLD see page 7 18 OFF Deactivate MAX HOLD display function highest measured value actions Default values see page A 1 e The current measurement value is output instead of the e The function is deactivated automatically for particular Table 7 8 Display function settings 7 11 7 Remote control ELT 400 7 12 SET MODE lt SP gt lt param gt CR lt LF gt SET MODE CR lt LF gt Response lt param gt lt CR gt lt LF gt Meaning Selects the operating MODE The operating modes are numbered consecutively 1 to 4 The mode assigned to each number depends on the instrument version param Explanation 1 Displays the first operating mode counting from the left hand side of the display LCD display elements see page 4 3 2 3 4 Displays the second third or fourth operating mode counting from the left hand side of the display Table 7 9 Operating mode settings Note T
38. has occurred gt Make a note of the error message Contact the Service Center 5 Operation and use ELT 400 5 3 2 The display shows the error message noPr The probe is not connected or has not been detected by the instrument gt Remove the probe and reconnect it Connecting disconnecting the B field probe see page 3 4 The display shows the error message unPr The unknown probe has been connected Connect the correct probe Connecting disconnecting the B field probe see page 3 4 Selecting the operating mode MODE The operating modes implemented in the instrument are shown below the display Operating modes see page 5 1 gt Press the MODE key until the arrow symbol in the display points to the required operating mode Note The measurement display will fluctuate whenever the setting is changed This fluctuation depends on the selected lower frequency range limit and may continue for several seconds particularly if 1 Hz or 10 Hz is selected Wait until the display has settled before starting measurements ELT 400 5 Operation and use 5 3 3 Selecting the detection mode DETECT Three modes of detection are available depending on the selected operating mode Detection mode Detector see page C 2 Detection mode Field strength mode Exposure STD mode STND Standard The detection mode specified in the appropriate standard is set automatically
39. he operating mode selected can also be queried as text information Remote control command GET MODE_INFO see page 7 8 ELT 400 7 Remote control SET RANGE lt SP gt lt param gt CR lt LF gt SET RANGE CR lt LF gt Response lt param gt lt CR gt lt LF gt Meaning Sets the measurement range for the selected operating mode param Explanation LOW Measurement range particularly suitable for low field strengths e High measurement sensitivity e Reduced overload capacity HIGH Measurement range suitable for higher field strengths e High overload capacity e Reduced measurement sensitivity Table 7 10 Measurement range settings 7 13 7 Remote control ELT 400 MEAS Meaning Transfers the measured values and where appropriate the status information Different modes for transferring individual values and for transferring values continuously are provided Remote control command Explanation MEAS CR lt LF gt Transfers the latest measured value status on request e Asynchronous query The same measured value is transferred several times if the query is made more often than the measurement value is updated measured value is refreshed 4 times per second MEAS ARRAY lt SP gt lt param gt CR lt LF gt Consecutive transfer of a selectable number of measured values statuses at regular intervals measured value is refreshed 4 times per sec
40. ing is changed This fluctuation depends on the selected lower frequency range limit and may continue for several seconds particularly if 1 Hz or 10 Hz is selected Wait until the display has settled before starting measurements 5 3 5 Selecting the measurement range RANGE The measurement range can be switched between HIGH and LOW settings depending on the measurement task If small field strengths are to be measured the accuracy of the measurement can be improved by selecting the LOW setting LOW High measurement sensitivity with limited overload capacity HIGH High overload capacity with limited measurement sensitivity Press the RANGE key until the required measurement range setting is made The display shows HIGH when HIGH range is selected or HIGH is no longer shown in the display when LOW range is selected ELT 400 5 Operation and use Note The measurement display will fluctuate whenever the setting is changed This fluctuation depends on the selected lower frequency range limit and may continue for several seconds particularly if 1 Hz or 10 Hz is selected Wait until the display has settled before starting measurements 5 3 6 Activating the MAX HOLD display function The default setting updates the current measurement values in the display continuously Activating the MAX HOLD function causes the highest level measured since activation of the MAX HOLD function to be displayed This considerably simplifies
41. ional area and the positioning of the measurement sensors i e distance from the field source significantly affect the results particularly in the near field e FFT analyzers usually show the results as peak values The corresponding reference values from the standard should be applied Spectral components must not be ignored The recording period of 1 second should also be taken into account If the results of isotropic three channel FFT analysis are combined the phase information is lost Linear summation of the individual results for each spectral line leads to a high measurement result that is usually much higher than the real value Annex C Instrument function Functional principle The voltage induced in the measurement coils field probe is evaluated in order to measure the magnetic flux density The signal voltages are digitized and evaluated by a digital signal processor DSP The DSP calculates the measurement result from the voltages The orthogonal configuration of the three measurement coils allows the field to be measured isotropically i e independent of spatial direction Block circuit diagram Scope output l B 7 o e Sensor o Fiter H Square 1 coil 1 1 1 ___Transferfunktion RMS average B l Result ote OA STND gt Select H Square T PEAK Ba l Fig C 1 Block
42. ld 4 1 5 11 C 6 Measured value 4 3 Measurement range 4 4 5 10 Mode 1 2 4 2 O ON OFF 4 1 Operating mode 4 5 5 1 5 8 Operating time 3 2 Oscilloscope 1 2 5 14 Overload display 5 13 Overload indicator C 6 Overload monitoring C 2 P Package contents 3 1 Packaging 3 1 Peak 5 9 C 2 C 3 Peak value C 3 Power supply 3 2 Probe configuration D 1 R Range 4 1 5 10 Rechargeable batteries 6 1 Remote control 7 1 Cleaning up received data 7 6 Querying instrument data 7 19 Response data characteristics 7 6 Response string 7 6 Setting the parameters to their default values 7 21 Use of remote control commands 7 3 Remote control commands Conventions 7 5 In measurement mode measuring 7 4 In ready mode status query 7 3 Remote control interface 8 7 RMS 5 9 C 2 RS 232 4 6 S Safety instructions 2 1 Scope 4 6 Settling time C 5 Specifications 8 1 Stnd Standard 5 9 C 3 Switching on 5 6 T Test setup 3 4 Transfer function C 2 Transport damage 3 1 U Unpacking 3 1 Ww Weight 8 10 Notes
43. mode used The crest factor peak RMS can be calculated from the RMS and peak values This gives the factor J2 fora pure sine wave signal only 5 12 ELT 400 5 Operation and use Possible faults The overload display appears b ICNIRP ICNIRP Gen Pub Occ Fig 5 6 Overload display The selected measurement range is unsuitable for the measurement task 1 Select HIGH range 2 Ifthe overload display is still shown increase the distance of the ELT 400 from the field source Selecting the measurement range RANGE see page 5 10 3 Deactivate the MAX HOLD function if it is activated MAX HOLD cannot be reactivated until the overload display has cleared Activating the MAX HOLD display function see page 5 11 Overload monitoring see page C 6 5 Operation and use ELT 400 5 4 5 14 Active probe using the three channel analog output The signal detected by the field probe measurement coils can be displayed for scientific applications or further analysis of the signal shape and freguency An oscilloscope or FFT analyzer can be connected to the analog signal output Scope of the ELT 400 for this purpose External connectors see page 4 6 The analog signal output provides the signal voltages for all three spatial axes with their correct phases and covers the entire bandwidth of the instrument The output is also affected by the measurement range operating mode and lower frequency
44. mputer Baud rate 19200 1 start bit 8 data bits No parity 1 stop bit Handshake XON XOFF ELT 400 7 Remote control 7 2 Fundamentals of remote control All settings can be made and results read out by remote control instead of manual operation Note The instrument parameters are set to defined default values if you switch the ELT 400 off and then on again before using it in remote control mode This also applies to various other operating actions Annex A Default values 7 2 1 Overview of remote control commands The ELT 400 runs through a test phase when you switch it on This tests important settings and instrument configurations The following remote control commands can be used to query or change the instrument status Remote control command IDN CR lt LF gt see page 7 19 SYST BAT CR lt LF gt see page 7 19 SYST DEFAULTS CR lt LF gt see page 7 21 SYST ERR CR lt LF gt see page 7 20 SYST KLOCK CR lt LF gt see page 7 16 SYST XONXOFF lt SP gt lt param gt CR lt LF gt see page 7 21 Table 7 1 Remote control commands for querying the instrument status The ELT 400 is in the measurement phase as soon as the test phase has been completed successfully 7 3 7 Remote control ELT 400 The following remote control commands can additionally be used in the measurement phase Remote control command CALC BAT lt SP gt lt p
45. onal takes place in the same way You therefore do not need to know the reference values at all ELT 400 Annex B Exposure STD mode Advantages of this method This method is particularly useful when the signal shape is unknown e g multiple frequency fields or pulsed fields The RMS and peak detectors ensure that such fields are evaluated properly The ELT 400 continuously and automatically selects the detectors that are appropriate to the standard Measurements and calculations are made continuously and without interruption This ensures that every pulse or change in the field is registered and measured correctly B 3 Annex B Exposure STD mode ELT 400 B 4 Please note When you compare the results from the ELT 400 in Exposure STD mode with those from other field measuring instruments some possible factors that need to be taken into account are e The comparison system must also measure isotropically and combine the results from the thee channels correctly e The different bandwidths and the lower frequency limits of comparison instruments can affect the results considerably e The broadband measurement most often used can only be used for single frequency fields This method does not give a reliable result if the signal shape is unknown Any frequency measurement that may be performed can be subject to extreme errors so it is impossible to stipulate the correct reference values e The effective cross sect
46. ond e Synchronous query Each measured value is transferred once only The transfer of the first measured value may be delayed slightly e param Number of measured values requested setting range 1 to 65535 e Transfer can be terminated prematurely using the command MEAS STOP MEAS START CR lt LF gt Continuous transfer of measured values statuses at regular intervals measured value is refreshed 4 times per second e Synchronous query Each measured value is transferred once only The transfer of the first measured value may be delayed slightly e Transfer is stopped with the command MEAS STOP MEAS STOP CR lt LF gt Stops continuous transfer 7 14 ELT 400 7 Remote control Response values lt d dddesdd gt lt unit gt ovld bat lt CR gt lt LF gt Example 1 234e 07 T N O Response Explanation unit Units of measured value depends on the operating mode selected by SET MODE e T Tesla in Field strength mode only e Percentage of limit value in Exposure STD mode only ovld Overload indicator for CALC OVLD ON only e N no overload measured value valid e overload state occurred during measurement reject measured value bat Battery status for CALC BAT ON only e L Battery is discharged e O Battery is charged Remote control command SET LOW_CUT see page 7 10 Remote control command CALC BAT se
47. rger unit vy 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 e 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 e 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 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 e The basic instrument e 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 non homogeneous fields Note Persons or objects should not come between the probe and the radiation source during the measurement 3 3 2 Connecting disconnecting the B field probe The multi pin connector so
48. rom 12h rechargeable batteries at 23 C approximate Charging time of 2h max or ELT 400 8 Specifications Primary batteries alkaline 4 x size AA IEC LR6 Operating time from primary 20 h alkaline batteries at 23 C approximate AC adapter charger unit Type BN 2259 92 02 9V Nominal voltage range 100 to 240 VAC Nominal voltage range Automatic universal line plug switching AC line frequency operating 47 to 63 Hz range Calibration interval The recommended calibration interval is 24 months 8 5 Conformance labeling Emissions and noise immunity acc to EN 61 326 1 and EN 61326 A1 Safety acc to EN 61 010 1 and EN 61010 1 A2 This fulfils the conditions required for affixing the CE conformance label 8 9 8 Specifications ELT 400 8 6 Climatic environmental conditions Environment classes Environment Storage Transport Operation class as per IEC 60721 3 Class 1K3 Class 2K4 2M3 Class 7K2 7M3 1M2 Low air temperature Air temperature restricted range extended excluding AC adapter Selected climatic parameters Storage Transport Operation Temperature 5 C to 45 C 30 C to 70 C 10 C to 50 C With AC adapter 5 C to 40 C Humidity 5 to 95 330 C 95 5 to 95 30 C 1 to 29 g m3 gt 30 c 45 C 1 to 29 g m gt 30 C Conden Yes Yes Occasional brief sation con
49. rument setting Magnetic stirring High field strengths e MODE very low frequencies Exposure STD Exp 1 occ e RANGE High e LOW CUT 1 Hz Household Low field strength e MODE Field strength 50 60 Hz 320 uT e RANGE Low e LOW CUT 30 Hz e DETECT RMS Induction heating High field strength e MODE melting 50 Hz to 20 kHz Exposure STD Exp 1 occ e RANGE High e LOW CUT 30 Hz Annealing tempering High field strength e MODE 10 kHz to 30 kHz Exposure STD Exp 1 occ e RANGE High e LOW CUT 30 Hz Resistance welding 50 Hz pulsed e MODE spot welding Exposure STD Exp 1 occ e RANGE High e LOW CUT 30 Hz MF welding Pulsed DC field with e MODE dominant component of Exposure STD Exp 1 occ converter frequency e RANGE Low e LOW CUT 1 Hz Table 5 1 Example applications and instrument settings 5 Operation and use Application Characteristic feature Recommended instrument setting Electronic article surveillance electromagnetic Complex pulse shape 20 Hz to 10 KHz e MODE Exposure STD gen pub e RANGE High e LOW CUT 10 Hz Electronic article surveillance magneto acoustic Complex pulse shape 58 kHz e MODE Exposure STD gen pub e RANGE Low e LOW CUT 30 Hz CE certification Product standard e MODE prEN 50366 household w 1 take coupling e RANGE Low appliances factor into account if e LOW CUT 10 Hz nec
50. the measurement of fields that vary over time and particularly of pulsed fields If required the highest field strength existing within the volume of a room can also be displayed by moving the instrument around the room with the MAX HOLD display function activated Activating the MAX HOLD function gt Press the MAX HOLD key until MAX appears in the display Deactivating the MAX HOLD function Press the MAX HOLD key until MAX is no longer shown in the display The current measurement value is now shown in the display 5 11 5 Operation and use ELT 400 5 3 7 Interpreting the measurement results ICNIRP ICNIRP Gen Pub Occ Fig 5 5 Measurement display showing measurement result No Explanation 1 Numerical value of measurement result The following applies to Exposure STD mode The percentage displayed refers to the limit value specified in the selected safety standard A measured value of 100 indicates that the limit value has been reached regardless of the frequency and signal shape Caution The results are calculated using standardized evaluation schemes in Stnd detection mode only 2 Measurement value units depend on the selected operating mode 3 Operating mode e The selected standard standard s name exposure range is displayed in Exposure STD mode e The end value RMS value of the measurement range is displayed in Field strength mode 4 Detection
51. the valid range To check the validity of remote control commands Remote control command SYST ERR CR lt LF gt see page 7 21 7 5 7 Remote control ELT 400 7 2 3 Response value formats Different formats are used for the values returned as responses by the ELT 400 Response strings are terminated with a Carriage Return and a Line Feed It is a good idea to filter out and delete unnecessary characters before subjecting the received data to further processing The following characters can be removed Leading spaces ASCII decimal character 32 Carriage Return ASCII decimal character 13 Line Feed ASCII decimal character 10 DC1 ASCII decimal character 17 DC3 ASCII decimal character 19 ELT 400 7 Remote control 7 3 Remote control commands All the remote control commands used for the ELT 400 are described in this section The commands are sorted according to their meanings Field probe SEN TYPE CR lt LF gt Response lt param gt lt CR gt lt LF gt Meaning Returns the type of field probe connected Response values param Explanation 0 No probe connected 1 to 99 Probe type identification 7 7 7 Remote control ELT 400 7 8 Measured quantity evaluation mode GET MODE_INFO CR lt LF gt Response lt param gt lt text gt lt CR gt lt LF gt Meaning Returns the operating mode that is selected param Explanation
52. trength 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 5 2 ELT 400 5 Operation and use 5 1 2 Field strength Broadband real time measurement of magnetic flux density RMS hu Da Da a mT bm hel hel Al 10Hz Max High h ICNIRP ICNIRP 1998 1998 320 pT 80 mT Gen Pub Occ Fig 5 2 Measurement display in Field strength mode Measurement goal Measurement of overall field strength Measured quantity RMS or peak flux density value Display Numerical display of measurement result in units of mT or uT Special features Flat frequency response Active probe The output field is available independent of frequency 5 3 5 Operation and use ELT 400 Example applications To take advantage of the full performance of the ELT 400 it is important to optimize the instrument settings to match the expected characteristics of the field being investigated The table below provides assistance for this important task It shows typical applications together with the appropriate instrument settings Please note though that the choice of measurement range or the lower measurement range limit in particular must be decided according to the actual measurement situation and the aim of the measurement Application Characteristic feature Recommended inst
53. tteries in household trash Return them to the appropriate recycling center 6 2 Cleaning e Do not use solvents to clean the casing or probes of the ELT 400 or the AC adapter charger unit Use lukewarm water to which a little liquid detergent has been added e Only use a slightly damp cloth for cleaning Never let water get into the instrument e To prevent drying marks and spots use a dry cloth to polish the damp surfaces of the instrument 6 3 AC adapter charger unit The AC adapter charger unit is not designed to be repaired The entire unit should be replaced if defects or malfunctions occur 6 2 7 Remote control 7 1 Setting up the data link You will need a suitable cable for making the link between the ELT 400 and the measurement computer It is available as an accessory BN 2260 90 51 7 1 1 Data cable DB9 plug Fig 7 1 DB9 plug connections Jack plug RxD TxD GND Fig 7 2 Jack plug connections Direction of data flow e RxD Data from ELT 400 e TxD Data to ELT 400 7 Remote control ELT 400 Connecting the instrument to the measurement computer 1 Plug the jack plug into the RS 232 socket on the ELT 400 2 Plug the DB9 plug into the serial interface connector COM of the measurement computer 7 1 2 Interface parameters The ELT 400 is connected to the PC The following parameters must be set for the serial interface of the co
54. 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 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 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 powere
55. 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 uT 5 Operation and use ELT 400 5 1 1 Exposure STD Shaped Time Domain Broadband measurement with simultaneous real time exposure assessment ICNIRP ICNIRP 1998 1998 320 pT 80 mT Gen Pub Occ Fig 5 1 Measurement display in Exposure STD mode 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 s
56. width limits see figure C 2 see figure C 3 Measurement range dynamic range All measurement range information depends on the settings selected Mode 320 uT 8 mT 80 mT Range Low High Low High Low High Overload limit C 32uT 320uT 800uT 8mT 8mT 80 mT Nominal 2 uT 20uT 50uT 500 uT 500uT 5mT measurement range Intrinsic noise RMS 7OnT 320nT 1 8uT 8uT 18uT 80uT approximate 1 The overload limit indicates the maximum measurable RMS value of a sine wave CW signal The frequency dependent damage level should also be taken into account 2 The nominal measurement range indicates the maximum measurable RMS value of a signal of any shape with a crest factor peak value RMS value of less than 22 The frequency dependent damage level should also be taken into account Display resolution 1 nT Range Low ELT 400 8 Specifications Damage level The freguency dependent overload limit shown in figure 8 1 must be taken into account in all measurements Damage Level 1000 00 mT 100 00 mT Hd 2 10 00 mT RMS CW Peak s ci 1 00 mT w 0 10 mT 0 01 mT t 1 He 10 He 100 Hz 1000 Hz 10000 Hz 100000Hz 1000000 Hz Frequency Fig 8 1 Damage level Note The damage level peak applies to a pulse duration of 45 6 ms and a duty cycle of 4 64 Measurement value collection S

Narda ELT-400 Exposure Level Tester User Manual

Contents

Download Pdf Manuals

Related Search

Related Contents