LAPLACE INSTRUMENTS LAPLACELL 600 User manual

LAPLACELL 600
Serial number 0619
USER GUIDE
Issue 3 September 2003
LAPLACEINSTRUMENTS LTD

CLIENTS user guide Introduction
Page 2
INDEX
1. INTRODUCTION
2. SPECIFICATION
2.1. Performance
2.2. Construction
2.3. Internalsensor
2.4. EUT I/O facilities
3. INSTALLATION
3.1. EUT Connections
3.2. RF Connections
4. EMISSIONS
4.1. Emission testnotes
4.2. Cell characteristics
4.3. Calibration
5. IMMUNITY
5.1. The standard
5.2. General requirements
5.3. The system
5.3.1. Interconnections
5.4. Calibration
6. ANNEX 1 CALIBRATIONDATA
6.1. Emissions
6.2. Immunity

CLIENTS user guide Introduction
Page 3
1.0 INTRODUCTION
The LaplaCell 600
This EMC test cell provides a fullycalibrated compact test facilityfor the hassle-free
measurement of the EMI/EMC performance of products.
* Immunity and emissions testing
* Emissions measurements correlated to OATS
* Immunitytestingto IEC61000-4-3
* Exceptionallycompact package.
The LaplaCellis the resultof an extensive R &Dprogramme to provide a solution to the several
problems facingorganisations who wish to self test products for EMC compliance. The unique
design features a novel double tapered internalprofile which provides a verycompact cell with a
built-in field sensor. Each cell is individuallycharacterised for field strength vs. sensor output
and for emissions sensitivityso that results can be correlated against an OATS.
The Laplace SA1000 emissions analyser (or anyother analyser/receiver) will work directlywith
the cell, enablingcompliance measurements to be made with ease, avoidingthe problems of
background radiation, testsite distortion and the need for ground planes and height scanning.
When used with the RF1000 synthesiser and RF1100 power amplifier, or anyother suitable
equipment, fullycompliant IEC61000-4-3 testing can be accomplished with ease at levels up to
10V/m. A high power version of the cell enables testingto 60V/m.
The cellthus provides the core of a totallyintegrated systemwhich willdeliver a complete, PC
controlled emissions and immunitytestpackage.
The design of the cell is derived from the developmentof the GTEM cell and others which
enable an RFsignalfed from a co-axial cable to be expanded in such a wayas to create a
reasonablyuniform field throughout a test volume. This action is reversible so that the cell can
be used for emissions as well as immunitytesting.
The cellprovides facilities for the connection of services and signals to the EUT, including
filtered connections for both power and signals.
The standard cellincludes:
• Mains power socket.
• Quantity10 signal terminations.
• Socketfor illumination and camera connection.
These connections have heavyfilteringand anyhigh speed data lines or signals with fast
edges willbe affected.
Options include:
• Illumination
• Camera
• Cooling
• Additional EUT interconnections
• High field strength version

CLIENTS user guide Introduction
Page 4
For immunitytesting the cellincorporates a calibratedfield sensor, avoidingthe use of a separate
sensor with associated fiber optic links. The factthat a direct connection is provided to the
sensor avoids the need to slow the response time of the sensor to conserve batterypower. The
settlingtime of this cell is consequentlymuch faster than with mostother types of cell.
The RF connector on the nose of the cellis used for both input of RF power for immunitytesting
and for output of signals when measuringemissions.
====================================================================
Full details ofthe individual test techniques are provided in the
following sections. Particular attention should be paid to the practical
notes sections for both immunity and emissions measurements.
====================================================================

CLIENTS user guide SA1000
Page 5
2.0 LaplaCell 600 Specification
2.1 Performance
General
Usable EUTvolume: 600mmcube
EUTweight: 100kg (Spreadload)
Internal size: 780mmx870mmx820mm
Calibrated frequencyrange: 30MHz - 2GHz (in two ranges)
Screeningattenuation: <60dB
Internal damping: Ferrite absorbers
Immunitymode
Max fieldstrengthwith
10W poweramplifier: 10V/mminimum
Fielduniformity: 6dB within EUTvolume measured as recommendedbyIEC
Power/field ratio: > 1.0V/m.per dB
Max input power: 50W
Sensor output level: 0 - 2.6V corresponding tointernal field strength.
Calibration data: Supplied witheach cell.
Sensor supply 12v dc input @800mA
Power input Impedance: 50ohm
Input VSWR: 1.5: 1
Input connector: N Type
Emissions mode.
Output Impedance: 50ohm
Output connector: N type
I/O facilities
Integratedfilter panel forpower andsignal connections into the cell.
Basic unit offers.... .mains input,
10waygeneral I/O
plus illumination and camera socket.
Additional interconnections maybe specifiedat time ofordering.
Monitoring
Optionals: Internal lighting
Internal video camera
Forced ventilation
Additional EUTconnections
Interlocks: Doorfittedwith safetyswitch.
Physical
Dooraperture: 520mmx840mm
Weight: 400kg
Size: length 3.15m
width 1.32m
height 1.57m
Outerconstruction: Stainless steel
Internal EUT chamber: Polypropylene.
Septum: Double tapered wire guided.

CLIENTS user guide SA1000
Page 6
2.2 Construction
The cellis a stainless steelfabrication with continuouslywelded joints all round, givinga totally
screened enclosure which is completelymaintenance free and willnot degrade with time. The
main bodyof the cell is made from 18swgsheet givinga verystrongconstruction.
The EUT usable area is contained within a Polypropylene enclosure. No internal parts of the cell
are accessible to the user.
The peripheryof the door mates with a mesh wire EMC gasket in the door frame so that the
integrityof the screeningis maintained. In the door frame a microswitch is located to detect
when the door is not fullyclosed.
At the nose of the cell, a switch is provided so thatthe frequencyrange can be selected. This
range can also be controlled via the 8 waycable connection to the system controlunit(normally
the RF1000 or RF2000). An Ntype connector and the 8 wayDIN connector provide the RF
input/outputand connections to the internalfield sensor respectively.
The RF connector is used as an input from an RF power amplifier for immunitytesting. For
emissions testingthis connector is connected to an emissions analyser.
The 8 wayDIN connector provides power to the internal sensor and the DC levelback fromthe
sensor to the field controlsystem(normallyprovided bythe RF1000 or RF2000).
Also wired via this connector is the door interlock signal.
The internal EUT volume is enclosed in a polypropylene liner. The base is designed to support
the weight of a person (100kg) butthe load must be spread, nota pointload.
Overalldimensions

CLIENTS user guide SA1000
Page 7
2.3 Internal sensor.
This sensor is built into the design of the cell. Itis arranged so as to provide an outputmatched to
the field strength as measured in the EUT volume.
A maximumoutput of 2.5 volts corresponds to a nominal full scale“. Standard cells are
calibrated to 20V/m.
Alternative models are calibrated to higher field strengths.
The field sensor requires a supplywhich is provided via an external unit to give 12v dc at
800mA.
Each cell is shipped fullycalibrated for sensor output vs field strength.
2.4 EUT input/output facilities
Comprehensive I/O filter facilities are provided at the rear of the cell. A cable ductbetween the
EUT volume and the filter unit is designed so that cable entryis quick and easy. Inside the filter
unita connection panel with mains socket and a quick connect terminalblock are provided. The
terminal block can acceptup to 10 connections. An additionalconnector provides an interface for
internallightingand a camera. (Optionalextras)
Within the bodyof the filter unit each connection is RFfiltered, then terminated on a matching
set of connectors.
2.5 Controls
The Lc600 has a dualfrequencyrange. An RF switch is located in the nose housingto switch
the connections between the two ranges. The frequencyatwhich the cellchanges range is
normallybetween 300 and 400MHz. Each cellis individuallyset atthe optimum change
frequencyand this is given in the calibration data.
Normally, the cell range control is driven byan external control system, such as the RF2000
synthesiser. However, for emissions measurement and if the RF2000 is not used, this switch
can be manuallycontrolled bya rotaryswitch on the side of the nose panel. See section 3.3.
2.6 Internal lighting and camera
The LAPLACELL600 is wired, via the ”filter box„, to allow the fittingof an internal camera and
lightingunitto externalpower supplies and a video monitor without introducingspurious
background noise.
An optionalmono minicamera system is available which can be positioned anywhere within the
testenclosure, This is fitted with a longrange adjustable power LEDlight source is integrated
within the camera unit.
A camera holder comprisinga U“section channel is included. The camera is a friction fit in this
channel such that its position can be altered to suit the application. This holder can be either
verticallyorientated on a free standingbase on the floor of the EUT chamber, or secured to the
roof such that the camera looks verticallydown. A tapped hole in the roof and a corresponding
hole in the holder facilitates this option, and permits the holder to be pivoted, thus coveringa
wide range of location options.
The camera position within the holder can be altered easilyas it is a simple friction fit.
The LED intensitycan be altered using the control on the top of the camera unit.

CLIENTS user guide SA1000
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Connections
Wiringfor the camera system is via a 5 pin 180°DIN connector (pin to pin through the filter
box) Power required for the camera systemis 12 volts dc 110mA.
Pin 1 - Camera - video Bottom leftpin
Pin 3 - Camera - 0 volts Top centre pin
Pin 5 - Camera - +12 volts Bottom right pin
Camera
The camera is supplied with a standard lens - other lenses allowingnarrower fields of view or
closer focussingare available.
The focus on the camera can be varied byscrewingthe lens assemblyin or out (the lens can be
unscrewed completely).
3.0 Installation
On arrival
If the cell has been shipped overseas, itwillprobablybe enclosed in a protective wooden crate.
To keep the crate within the international size restrictions for air freight, the heightof the crate is
limited to 1.6 metres. To keep within this limit, the castor wheels on the cell are detached and
packaged separatelywithin the crate. Instructions for the re-assemblyof these castors is provided
with the shippingdocuments, but is repeated here in case the shippingdocuments are mislaid.
• The castors, mountingbolts and a 17mm spanner are allboxed with the cell. Note that the
swivel caster is mounted at the ”sharp end„.
• To re-assemble, lift the cell and temporarilysupport it on wooden blocks such that the castors
can be fitted. (Mountingbolts willbe with the castors). Once the castors aresecurelyfixed,
the cellcan lifted, blocks removed and lowered onto the wheels.
• The cellwillmove easilyon its castors. Note thatthe castors can be locked when the final
location is achieved. When movingthe cell, ensure that the nose section does notcome into
contactwith anyother surface or damage to the connectors or switch mayresult.
Connection
Before applying power to the chamber, a protective earth must be fitted. A ringterminal has been
supplied for this purpose.
Maximum input voltages and currents to the connectors must be observed. Exceedingthe
stipulated ratings maycause permanentdamage to the filter assembly.
Figure 1 Lower viewof rear of cellshowingconnections to the externalworld.

CLIENTS user guide SA1000
Page 9
Panelfor external connections including mains
power, camera, general purpose I/O and any
customconnections as specfied
Maintenance
No routine maintenance is required for the chamber.
Calibration
Annual calibration is recommended. Call your local representative for details.
Access
The onlyaccess into the cell is via the hinged door. When testing, this mustbe clamped in
the closed position with the camplates. On no accountmust anyother parts of the cell be
disturbed as this mayaffect calibration.

CLIENTS user guide SA1000
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3.1 EUT Inputs and Outputs
Connections to the EUT are provided at the rear of the cell. Externalconnections are made at the
lower face of the filter unit, see figure 1 above. Mains, generalI/O, camera and cellillumination
connections are provided. Allconnections pass through the filter unit to matchingconnectors
inside the top section. See figure 2. From these internal connectors, cables maybe run through
the access duct to the EUT inside the cell.
The followingratings are the maximumpermissible
1. IEC mains inlet 240V ac, 10A
2. Wago cage clamp 240V ac, 6A/connector
3. 5 pin DIN skt (Camera &lighting) 50V dc, 0.5A
Other customconnections willbe as specified.
At the front of the cell, the following connectors are provided:
N“type RFconnector RF input & output only, 30MHz-2GHz, 30W,
50ohm
8 pin DIN, lockingskt Cell control, probe and interlock only
Jack socketfor 12v dc power.Requires 12v dc at 800mA, centre pin +ve.
Jack socketfor door interlock cable. Connect to filter unit panel with supplied cable.
EUT connections
The IEC and Wago EUT connections are pifiltered usingfeedthrough filters with a capacitance
to ground of 5nF. High speed data transmission lines and low power analogue drivers maybe
compromised bythis capacitance.
For data communications lines, a common mode inductivelyfiltered systemcan be provided.
Inductive filteringdoes not attenuate external noise or confine RFpower to the same extent.
To connect a wire into the Wago cage clamp, a flat bladed screwdriver 3.3-4.0mm wide or a
proprietarytoolis needed. Insert the toolinto the cage clamp, perpendicular to the connector
mountingplate and applya pressure of approximately80 Newtons. The clamp will open while
pressure is applied and a wire can be inserted into the receptacle at right angles to the tool.
Releasingthe pressure allows the clamp to secure the wire. Single core or stranded cable can be
used with equal effect.
The mains outletsocket is normallya UK square pin type. A short mains cable to IEC connector
is provided, together with adaptors for European (Schuko) and US mains connectors.
The data link connectors are allwired with twisted pair cables inside the filter.

CLIENTS user guide SA1000
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Figure 2 Typical connections at filter unit
Figure 3 Rear view of cell showingfacilities for connections to EUT inside the cell.

CLIENTS user guide SA1000
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3.2 RFconnections
The RF connection to the cell is mounted on the nose panel, see figure 4.
It is recommended that once the main RF cable has been attached to the chamber, it should never
be disconnected from thatend. This is to preventthe possibilityof inadvertentdamage to the
inputconnector. Replacement of the RF input connector or the probe connector should never be
attempted bythe user.
3.3 Controls
On the side panel of the nose unit
The key control is the frequencyselector switch. This can be set to either .
Auto automatic control when usingthe cellwith the RF1000 or RF2000.
Hi - manuallysets the cell to high range (overrides the Auto setting). The high range is
approx 340MHz 3GHz.
Lo - manuallysets the cell to lowrange (overrides the Auto setting). The lowrange is
30MHz approx 340MHz.
Figure 4 Control panel

CLIENTS user guide SA1000
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4.0 Emission Measurements
4.1 Practical notes
The Lc600 cell has a dual range technologywhich enables it to performover a wide frequency
range, from 30MHz to well above 3GHz.
When makingemissions measurements, the EUT should initiallybe placed on the floor of the
testvolume, in the centre of the chamber. Cables should be arranged such that theyrun near
vertically from the floor of the EUT testvolume to the cable port. This maximises the potential
emissions due to cable borne interference.
Cables should be prepared to an appropriate length before attachingto the EUT. Results may
become inconsistent if excess cable is allowed to come into contact with the metalwalls of the
filter boxassembly. Anyexcess cable mustbe bundled in a non-inductive manner and kept
within the EUT test volume. Do not allow excess cable in the filter connection compartment.
Multiple scans should be taken with the EUT in different positions and orientations, as it is
possible for the emissions to be directional and/or to take into account variations in sensitivity
within the EUT test volume, particularlyat frequencies above 500MHz when cell dimensions
and reflection paths become equal to wavelength.
Duringthese multiple scans, a peak hold systemshould be used which willrecord the highest
levels attained across allthe scans. For typical products, a total of 12 scans for 4 locations within
the celland with three orientations at each location. The orientations should be:
1. Front face of the EUT towards the celldoor
2. Front face of the EUT towards the cell nose“end.
3. Front face of the EUT facingupwards.
If the producthas more than one operatingmode or configuration, the tests mayneed to be
repeated for each mode and configuration.

CLIENTS user guide SA1000
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4.2 Cell characteristics
The cellmaybe distinctlynon linear in frequencycharacteristics. Generallyeach cellis
individuallycalibrated bythe manufacturer and the resultant characteristics programmed into the
software.
The calibration data for this cell is supplied on the 3.5„disk included with this shipment.
4.3 Calibration - Emissions
The nominalA.F. is the correction applied to results from the cell to convertthem to levels as
measured on a three metre OATS. When emissions testinginside LaplaCell, GTEM or other
EMC test cells specialcare must be taken to avoid the effects of the unavoidable variabilityin
cell performance throughout the test volume. The calibration technique is derived from thatused
byNPLand takes account of this variability. The draft standard which relates to the calibration
of test cells (IEC61000-4-20) is also based on these NPLtechniques. Calibration is accomplished
with an Emissions Reference Source, traceable back to NPL, London. This source is scanned 12
times, each scan at a different location in the cell. The locations are:
1. Centre front 7. Mid front corner
2. Centre 8. Mid side
3. Centre back 9. Mid back corner
4. Top frontcorner 10. Top side corner
5. Top centre 11. Top mid corner
6. Top back centre 12. Top rear corner
Figure 5. Calibration locations.
This effectivelycalibrates one quadrant of the cell. Checks confirmthat the other quadrants
replicate this quadrant.
At each frequency, the results of all 12 locations are compared. The 4 lowest readings are
discarded and the remaining8 averaged to provide the calibration data. This technique is as
defined in IEC publications for the calibration and use of GTEM cells.
The results obtained from a typical cell calibration are plotted in figure 6.

CLIENTS user guide SA1000
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Individual plotsforeach locationinEUTvolume(Cell020)
0
10
20
30
40
50
60
70
0 100 200 300 400 500 600 700 800 900 1000 1100
Frequency(MHz)
Output (dB)
Figure 6. Measurements of the ERS at 12 locations in one quadrant of the test volume.
The antenna factor“(A.F.) or correction data“or calibration factor“can be calculated for each
location byusingthe calibration data for the ERS.
At each 2MHzfrequencystep:
AF(cell) = ERS(dB) - cell(dB)
So if the ERS has been measured as 56dBuV/m on the NPL3 metre test site, and the ERS is
measured as 62dB in the test cell, then the cell A.F. is 56 - 62 = -6dB.
Figure 6 shows how especiallyathigher frequencies, some locations give different results. This
is a common feature of GTEM and similar cells. It happens when the wavelength becomes
comparable with the physicaldimensions of the cell. In particular note how narrow dropouts“
occur when the cell effectivelybecomes less sensitive. These representsmall dead“zones in the
testvolume. The standard technique to ensure thatthese do not cause significantmeasurement
errors is to scan the EUT several times, each scan with the EUT is a different location. Thefinal
resultis taken as the peak readingat each frequencystep across allthe scans.
To calculate the cellcalibration, the followingprocedure is used:
For each frequencystep....
Listall 12 measurements (correspondingto the 12 locations) and discard the 4 lowest.
Average the 4 highestreadings.
Check that the highestreadingis within 4dB of the average.
Usingthe average and the ERS data, calculate the A.F. of the cell.

CLIENTS user guide SA1000
Page 16
ERS cal data
20
30
40
50
60
70
80
0 100 200 300 400 500 600 700 800 900 1000
Figure 7. ERS calibration data
The ERS data used for the calibration is shown in figure 7.
Comparison of actual and highest/lowest A.F. values (Cell 020)
-20
-10
0
10
20
30
40
50
0 100 200 300 400 500 600 700 800 900 1000
Frequency (MHz)
Antenna Factor (dB)
Figure 8. Cell Antenna Factor for 3 metre OATS
The thick line shows the cell A.F. as calculated usingthe above procedure. The lower thin line is
the A.F. calculated usingthe highestreadingand the upper thin line is the A.F. calculated using
the lowestreadingafter discardingthe 4 lowest.

CLIENTS user guide SA1000
Page 17
-20
-15
-10
-5
0
5
10
15
20
30 230 430 630 830
Worst case AF dev (L)
Worst case AF dev (H)
Figure 9.
This shows the maximum errors as derived fromfigure 8. As can be seen, in no circumstances
can a high readings of more than 4 dB be obtained, however, low readings over 10 dB are
possible above 600MHz. It is these errors which require the use of several scans in order to
avoid obtainingfalse results.
Error after random 4 locations
Three differentcombinations of 4 plotted
-10.00
-8.00
-6.00
-4.00
-2.00
0.00
2.00
4.00
6.00
8.00
10.00
0 200 400 600 800 1000 1200
MHz
Error (dB)
Typical 4B, D, H, J
Typical 4C, E, F, K
Typical 4D, F, I, M
Figure 10
This shows the results of taking4 scans with the EUT in different locations for each scan and
applyingpeak hold across all 4 scans. This test has been repeated 3 times, each with a different
combination of locations, selected at random. The 4 locations selected for each testare shown on
the plot (e.g. B, D, H, J)
As can be seen, measurement uncertaintybelow 600MHz is now 2dB and above 600MHzitis
now around 4dB. These results are comparable with those obtainable on the best OATS sites.

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Error distribution (% of frequencies)
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
-6.00 -4.00 -2.00 0.00 2.00 4.00 6.00
Deviation (dB)
Percent scan readings
B,D,H,J
C, E, F, K
D, F, I, M
Figure 11
This shows the error distribution for each of the three tests above.
The percentage of results within 2dB of the actual is89.96%, 87.91% and 92.83% respectively
and within 3dB the figures are 96.31%, 97.34% and 97.34%. This shows that the choice of
locations within the volume will have an effect on the results, but as figure 6 graphicallyshows,
the effectis marginal. Takingmore that 4 scans (4 locations) willimprove the results, butthe law
of diminishingreturns will apply.
All the above tests have been undertaken with a compact source (the ERS). An EUT with cables
or larger distributed sources would increase the measurement uncertainties. The degree of
increase is entirelydependant on the detail of the EUT, cables and the rigourwith which the
testingis accomplished.

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5.0 Immunity
5.1 IEC61000-4-3
IEC61000-4-3 immunitytestingrequires thatthe EUT (equipment under test)operates
satisfactorilywhen subject to a strong electromagnetic field.
Thisrequires a scan at acertain fixed level (specified bythe standard) of field strength. The
scan will comprise aseries of steps“in frequency.Each step is specified as apercentageof
current frequencyvalue.
This percentage is variable from0.1% to 15%.
At each step,the frequencyis held, the level adjusted toachieve the required field strength as
measured byafieldsensor, aprescribed modulation mode isinitiated and then the conditions
held for a dwelltime. The EUT should be monitored to detect faultyoperation duringthe test.
Duringthe dwell time, a 1KHz, AM modulation at 80% depth is applied to the signal.
Inaddition, aspecifictestisrequired at900MHz with apulsed modulation of 100% depth to
simulate the fields which maybe experienced frommobilephones.
5.2 General immunity requirements
The strategyfor immunitytestingis similar to that of the emissions tests described above.
Immunityscans should be carried out with the product in three perpendicular orientations and in
atleast 4 locations within the cell. One location should be central in the EUT test volume. If the
productis relativelysmall, place it on a plastic or wooden stand to liftitcentral. The side of the
testchamber opposite to the door is positioned so that products can beplaced up against that
surface. Always ensure that the product and anyassociated cablingis kept at least100mmaway
from the door as this is an un-calibrated area.
An interlock is fitted to the door that inhibits the amplifier outputwhen the door is open. Both
door latches should be fastened when closingthe door. A mesh window in the door can be used
for viewingthe EUT duringtesting. Illumination and a miniature camera can also be used to
monitor the EUT. Connections for a camera and light are supplied as standard.
5.3 Complete system
The diagram(figure 12) below shows the arrangement for immunitytesting.

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Figure 12. Immunitytestingconnections
5.3.1 Field probe and door interlock connections
The 8 pin DIN connector on the nose of the cell mustbe connected to the control system for
immunitytestingif usingthe RF2000. The wiringinformation is shown in the diagrambelow.
If usingthe Laplace RF2000 synthesiser, an 8 waycable is included with the system, otherwise a
matingconnector is supplied.
Pin number Function
1 Hi - Field strength feedback (0 …2.5v)
2 Lo - Field strength feedback. (0v)
3 Door interlock (closed when door open)
4 0V
5 Not used
6 Range control, pull down for Lo range
7 High range selected (acknowledgement signal)
8 Low range selected (acknowledgementsignal)
5.3.2 Connectors
RF …N type, 50R
Controlcable: Binder, series 680, metal body
DC power in: 2.1mm DC power jack