User's Manual

1/28/2015 LMU42x0Hardware&InstallationGuidePULSWiki
https://puls.calamp.com/wiki/LMU42x0_Hardware_%26_Installation_Guide 7/47
ElectrostaticDischarge(ESD)
Electrostaticdischarge(ESD)isthesuddenandmomentaryelectriccurrentthatflowsbetweentwoobjectsat
differentelectricalpotentialscausedbydirectcontactorinducedbyanelectrostaticfield.Thetermisusually
usedintheelectronicsandotherindustriestodescribemomentaryunwantedcurrentsthatmaycausedamageto
electronicequipment.
ESDHandlingPrecautions
ESDpreventionisbasedonestablishinganElectrostaticProtectiveArea(EPA).TheEPAcanbeasmall
workingstationoralargemanufacturingarea.ThemainprincipleofanEPAisthattherearenohighly
chargingmaterialsinthevicinityofESDsensitiveelectronics,allconductivematerialsaregrounded,workers
aregrounded,andchargebuilduponESDsensitiveelectronicsisprevented.Internationalstandardsareused
todefinetypicalEPAandcanbeobtainedforexamplefromInternationalElectrotechnicalCommission(IEC)
orAmericanNationalStandardsInstitute(ANSI).
ThisESDclassificationofthesubassemblywillbedefinedforthemostsensitivecomponent,thereforethe
followingclassificationsapply:
Class1B–HumanModel(<1kV)
ClassM1–MachineModel(<100V)
WhenhandlingtheLMU42x0’s™mainboard(i.e.subassembly)byitselforinapartialhousingproperESD
precautionsshouldbetaken.ThehandlershouldbeinanESDsafeareaandbeproperlygrounded.
GPSCeramicPatchHandling
Whenhandlingthesubassemblyitmaybenaturaltopickitupbysidesandmakecontactwiththeantenna
boards.InanuncontrolledESDenvironmentcontactwiththecenterpinofceramicpatchantennacancreatea
pathforelectrostaticdischargedirectlytotheGPSModule.TheGPSModuleisverysensitivetoESDandcan
bedamagedandrenderednonfunctionalatlowlevelsofESD.
Oneshouldavoidcontactwiththecenterpinofthepatchduringhandling.TheFactorywillbeplacinga
protectivelayerofKapton®tapeoverthepatchelementtoeliminatethisESDpath.
Packaging
Anytimethesubassemblyisshippedanditisnotfullypackagedinitsfinalhousingitmustbesealedinan
ESDsafebag.
ElectricalOverStress(EOS)
TheGPSreceivercanbedamagedifexposedtoanRFlevelthatexceedsitsmaximuminputrating.Such
exposurecanhappenifanearbysourcetransmitsanRFsignalatsufficientlyhighleveltocausedamage.
StorageandShipping
OnepotentialsourceofEOSisproximityofoneLMU42x0™GPSAntennatoanotherLMU42x0™GSM
Antenna.Shouldoneoftheunitsbeinatransmitmodethepotentialexistsfortheotherunittobecome
damaged.ThereforeanyLMU42x0™GPSAntennashouldbekeptatleastfourinchesapartfromanyactive
LMU42x0™GSMAntennaoranyotheractivehighpowerRFtransmitterwithpowergreaterthan1Watt.