User manual

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 DocumentMT0100P.N

©XsensTechnologiesB.V. MTiandMTxUserManualandTechnicalDocumentation

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Triggerthesamplingoftheinternalsensors

InthisSyncInmodetheexternalsignalconnectedtotheSyncInlineoftheMTi/MTxstartsthesampling(AD

conversion) of the sensor signals, i.e. accelerations, rate‐of‐turn, magnetic field and temperature. Next,

dependingontheOutputMode,thephysicalcalibrationandthe sensorfusion(XKF)arestarted.Ifalldatais

processed it will be transmitted at a rate depending on the OutputSkipFactor (see MTi and MTx Low‐Level

CommunicationDocument).

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InthisSyncInmodeitisimportanttosettheMTi/MTxsamplefrequencytothesamefrequencyasthetrigger

signal.FurthermorethetriggersignalshouldhaveatleastthesameaccuracyastheinternalclockoftheMTi/

MTx(seesection5.6).Thisisbecausethestoredsamplefrequencyisusedinthesensorfusioncalculationsand

isnotcorrectedbydeviationsinthetriggersignal.Iftheaccuracyisnothighenoughorthesamplefrequency

cannotbeaccuratelymatchedyoumustchoosethefirstSyncInmode(transmissionoflatestdata).Moreover,

asamplefrequencybelow100HzisnotsupportedbytheMTi/MTxsinceitwouldcompromisetotalaccuracy,

so the trigger frequency must be at least 100 Hz. Note that the output frequencies lower than 100 Hz are

supported.

5.5.2 MTi/MTxtriggersexternaldevices

IncasetheclockspecificationoftheMTi/MTxisaccurateenoughforthemeasurement,theMTi/MTxcan

provide a sync pulse which is generated based on its internal clock. For more details on clock accuracy see

section 5.6. The sync pulse or SyncOut signal will mark the time instance at which the MTi /MTx starts 

samplingtheinternalsensors

andcontinuedoingthiswhiletheMTi/MTxisinmeasurementstateandwith

thefrequencyrelatedtothecurrentsamplefrequency.Thesignalcanbesettoeitherpulseortogglemode

andincaseofpulsemodethepolaritycanbesettonegativeorpositive.Formoreinformationaboutenabling

SyncOutanditssettingsseeMTiandMTxLow‐LevelCommunicationDocument.

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To connect the SyncOut signal to an external device you can either make a custom cable that wires the

SyncOutpin(seesection6.4)directlyfromtheMTi/MTxorin caseyouusetheUSB‐serialdataandpower

cableyoucanuseaspareheaderintheUSBconverterforaconnectiontotheSyncOutline(seesection6.4.1).

Thisconfigurationisshowninthenextfigure.

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NOTE:Alwayscheck iftheinput voltage levelsandtheinput impedanceof the externaldevicematches the

SyncOutspecifications(seesection6.4).

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ThefollowingMTidevicessupportSyncOut:MTi‐28A##G##(MTiRS‐232)andMTi‐48A##G##(MTiRS‐485).



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ProvidedthattheSyncOutoffsetsettingiszero.

USB

Converter

Trigger Input

External

device

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