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NARDA ELT-400, Operating Manual

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ELT-400

5  Operation and use

5-3

5.1.2

Field strength

Broadband real time measurement of magnetic flux density

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 

µ

T.

Special features:

Flat frequency response

Active probe:

The output field is available independent of frequency.

Summary of Contents for ELT-400

Page 1: ...ELT 400 Exposure Level Tester Operating Manual BN 2300 98 11 Advanced Test Equipment Rentals www atecorp com 800 404 ATEC 2832 Established 1981...

Page 2: ......

Page 3: ...ELT 400 Exposure Level Tester BN 2304 xx Series A Operating Manual...

Page 4: ...ontact 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 g...

Page 5: ...ng 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 rechar...

Page 6: ...ng 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...

Page 7: ...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 envir...

Page 8: ...Notes...

Page 9: ...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...

Page 10: ...irectly 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 Th...

Page 11: ...rence 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 fu...

Page 12: ...1 Introduction ELT 400 1 4 Notes...

Page 13: ...some radiation sources 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 v...

Page 14: ...ion Malfunctions Incorrect usage damage and impermissible repairs can adversely affect the accuracy and function of the instrument Only use the instrument under the conditions and for the purpose for...

Page 15: ...posed if the AC adapter charger unit is damaged Do not use an AC adapter charger unit that has been damaged Caution Destruction The wrong AC line voltage condensation excessively high or low temperatu...

Page 16: ...2 Safety instructions ELT 400 2 4 Notes...

Page 17: ...ories 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 Reco...

Page 18: ...e 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 incor...

Page 19: ...egments 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...

Page 20: ...n the probe and the radiation source during the measurement 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 T...

Page 21: ...ELT 400 3 Preparation for use 3 5 Disconnecting the field probe Hold the field probe by the locking sleeve and pull it off the basic instrument...

Page 22: ...3 Preparation for use ELT 400 3 6 Notes...

Page 23: ...ttings 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 Activ...

Page 24: ...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 det...

Page 25: ...elements 4 3 4 2 LCD display 4 2 1 LCD display elements Fig 4 1 LCD elements example No Function 1 Measured value including units The units depend on the selected measurement mode T mT Table 4 2 LCD d...

Page 26: ...teries fully discharged or not fitted The battery symbol is no longer displayed at all Charging with AC adapter charger unit connected Outer frame displayed Inner segments flash to indicate the charge...

Page 27: ...g 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 mi...

Page 28: ...Socket Function RS 232 Serial data interface Computer PC connection 19200 baud 8n1 Handshake XON XOFF For pin connections see Fig 7 1 Scope Analog signal output active probe Connection to oscilloscop...

Page 29: ...vantages 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 with...

Page 30: ...id 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 st...

Page 31: ...surement 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...

Page 32: ...plication Characteristic feature Recommended instrument setting Magnetic stirring High field strengths very low frequencies MODE Exposure STD Exp 1 occ RANGE High LOW CUT 1 Hz Household Low field stre...

Page 33: ...ticle surveillance magneto acoustic Complex pulse shape 58 kHz MODE Exposure STD gen pub RANGE Low LOW CUT 30 Hz CE certification household appliances Product standard w 1 take coupling factor into ac...

Page 34: ...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 During the function t...

Page 35: ...s off Possible faults No display after switch on The rechargeable batteries or alkaline batteries are completely discharged Recharge the batteries or replace the alkaline batteries Charging the rechar...

Page 36: ...the B field probe see page 3 4 5 3 2 Selecting the operating mode MODE The operating modes implemented in the instrument are shown below the display Operating modes see page 5 1 Press the MODE key un...

Page 37: ...eld strength mode Exposure STD mode STND Standard The detection mode specified in the appropriate standard is set automatically You can also select RMS and PEAK detection if required x RMS root mean s...

Page 38: ...surement 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...

Page 39: ...ting the MAX HOLD function causes the highest level measured since activation of the MAX HOLD function to be displayed This considerably simplifies the measurement of fields that vary over time and pa...

Page 40: ...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...

Page 41: ...t HIGH range 2 If the 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 or 3 Deactivate the MAX HOLD functi...

Page 42: ...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...

Page 43: ...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 Exposu...

Page 44: ...5 Operation and use ELT 400 5 16 Notes...

Page 45: ...partment 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 Fig 6 1 Polarity markin...

Page 46: ...se 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 Only use a slightly damp cloth for cleaning...

Page 47: ...or 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 Fig 7 2 Jack plug con...

Page 48: ...t 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...

Page 49: ...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...

Page 50: ...SP param CR LF see page 7 18 GET MODE_INFO SP STD name CR LF see page 7 8 MEAS CR LF see page 7 14 SEN TYPE CR LF see page 7 7 SET DETECTOR SP param CR LF see page 7 9 SET LOW_CUT SP param CR LF see...

Page 51: ...utside the valid range To check the validity of remote control commands Remote control command SYST ERR CR LF see page 7 21 Character Meaning Instrument parameter measurement value query param Instrum...

Page 52: ...rriage 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 Leadin...

Page 53: ...used for the ELT 400 are described in this section The commands are sorted according to their meanings Field probe SEN TYPE CR LF Response param CR LF Meaning Returns the type of field probe connected...

Page 54: ...rating mode that is selected Note The length of text is limited to 30 characters param Explanation 0 Field strength mode 1 Exposure STD mode Table 7 4 Operating mode characterization text Explanation...

Page 55: ...de 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...

Page 56: ...nse param CR LF 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...

Page 57: ...activated is output instead of the current measurement value The status of the overload display takes into account the instrument status since the function was activated Remote control command CALC OV...

Page 58: ...the instrument version Note The operating mode selected can also be queried as text information Remote control command GET MODE_INFO see page 7 8 param Explanation 1 Displays the first operating mode...

Page 59: ...for the selected operating mode param Explanation LOW Measurement range particularly suitable for low field strengths High measurement sensitivity Reduced overload capacity HIGH Measurement range sui...

Page 60: ...tive transfer of a selectable number of measured values statuses at regular intervals measured value is refreshed 4 times per second Synchronous query Each measured value is transferred once only The...

Page 61: ...page 7 18 Response Explanation unit Units of measured value depends on the operating mode selected by SET MODE T Tesla in Field strength mode only Percentage of limit value in Exposure STD mode only...

Page 62: ...ent 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 param Explanation ON Locks the basic instrument keypad...

Page 63: ...ctivates deactivates battery status information The battery status is appended to the response values for a field measurement Remote control command MEAS see page 7 14 param Explanation ON Battery sta...

Page 64: ...d to the response values for a field measurement Remote control command MEAS see page 7 14 MEAS BAT CR LF Response param CR LF Meaning Queries the current battery voltage measured value units separate...

Page 65: ...appearance of the BAT_LOW message The instrument will then switch off automatically IDN CR LF Response Returns the following information separated by commas Manufacturer Instrument name Article number...

Page 66: ...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 29...

Page 67: ...ng the default values SYST DEFAULTS CR LF Meaning Sets the instrument settings to their default factory values Annex A Default values The instrument information and the current measurement units are a...

Page 68: ...7 Remote control ELT 400 7 22 Notes...

Page 69: ...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 p...

Page 70: ...ount 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 s...

Page 71: ...e duration of 15 6 ms and a duty cycle of 1 64 Measurement value collection Sampling frequency 1 048576 MHz Measurement interval measurement rate 250 ms 4 per second RMS RMS value detector Continuous...

Page 72: ...the selected band limits 10 Hz 30 Hz 400 kHz 3 dB 1 dB 1 Hz 3 dB 2 dB Sufficient signal to noise ratio Result display Measurement uncertainty 4 50 Hz to 120 kHz Result display selectable Instantaneous...

Page 73: ...calculated simultaneously 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...

Page 74: ...00 160 1600 Nominal measurement range 10 100 10 100 Intrinsic noise approximate 1 3 6 0 4 1 6 Display resolution Range Low 0 001 Sampling frequency 1 048576 MHz Measurement interval measurement rate 2...

Page 75: ...selectable Instantaneous value or maximum value MAX HOLD Display type Digital Digital display resolution 4 digits Refresh rate 4 times per second Units Percent Display type LCD display with backlight...

Page 76: ...ance 10 kohm Channel configuration See Annex D Probe configuration Effective coil cross sectional area 100 cm2 Construction features 3 coils arranged orthogonally common center point Orientation See A...

Page 77: ...formance label Primary batteries alkaline 4 x size AA IEC LR6 Operating time from primary alkaline batteries at 23 C approximate 20 h Type BN 2259 92 02 9V Nominal voltage range 100 to 240 VAC Nominal...

Page 78: ...7K2 7M3 Low air temperature restricted Air temperature range extended excluding AC adapter 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 Hu...

Page 79: ...H 80 mT BN 2304 101 EXPOSURE STD BGV B11 EXP2 EXPOSURE STD BGV B11 EXP1 EXPOSURE STD BGV B11 2H D FIELDSTRENGTH 8 mT BN 2304 102 prEN 50366 EXPOSURE STD ICNIRP occ FIELDSTRENGTH 320 T FIELDSTRENGTH 80...

Page 80: ...ent length 1 m 2300 90 30 RS 232 interface cable length 2 m with jack plug DB9 plug 2260 90 51 Analog interface cable D Sub 15 3 x BNC length 3 m 2260 90 80 Tripod non conductive height 1 65 m 2244 90...

Page 81: ...he operating mode shown farthest to the left on the basic instrument DETECT detection mode Depends on the mode selected RMS if a field strength mode is preset STND if an Exposure STD mode is preset MA...

Page 82: ...Unchanged MAX HOLD display mode OFF OFF OFF OFF LOW CUT lower frequency range limit Unchanged Unchanged As set Unchanged Measured values display status of the following instrument functions RMS PEAK...

Page 83: ...in units of field strength mT to assess the exposure level For this reason the result displayed in Exposure STD mode is not the measured field strength but rather the exposure level in percent as alre...

Page 84: ...are taken from ICNIRP 1998 The corresponding reference values are 100 T and 33 3 T i e the permitted values differ by a factor of 3 If the field at 50 Hz is attenuated by the filter during the measur...

Page 85: ...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 Measur...

Page 86: ...unknown Any frequency measurement that may be performed can be subject to extreme errors so it is impossible to stipulate the correct reference values The effective cross sectional area and the positi...

Page 87: ...ic 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...

Page 88: ...splayed RMS value The RMS value of the magnetic flux density is calculated from the RMS values for each of the three measurement axes i e to The RMS value is always independent of the time phases of t...

Page 89: ...he 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...

Page 90: ...tion ELT 400 C 4 Band limits The signal is attenuated according to the following function at the upper and lower limits of the frequency range Fig C 2 Lower band limits LOW CUT 1 Hz 10 Hz and 30 Hz Fi...

Page 91: ...ted 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 frequen...

Page 92: ...displayed if an overload occurs in at least one of the channels 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 st...

Page 93: ...ust be configured so that they match the spatial axes of the room Use the diagram below to position the probe correctly Fig D 1 Probe configuration Positioning the probe Tilt the ELT 400 up by exactly...

Page 94: ...Connecting cable The following connections are provided if the analog interface cable BN 2260 90 80 is used Koax plug Red X axis Green Y axis Blue Z axis DB9 plug Fig D 2 DB9 plug connections 1 X Axis...

Page 95: ...ELT 400 B field probe connector RS 232 Scope Charge...

Page 96: ...Notes...

Page 97: ...alibration 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...

Page 98: ...ange 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...

Page 99: ...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 W Weight 8 10...

Page 100: ...Notes...

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