Simrad SU90 - Synchronisation Using a Serial Line; SU90 Set up as Slave; SU90 Set up as Master

SimradSU90
Synchronisationusingaserialline
Inmostapplications,thesynchronisationinterfaceisbasedonanRS-232serialport.
OnlytheCTSandRTSconnectionsoftheRS–232interfacearethenused.
AccordingtothestandardspecicationsforRS-232,anoutputmustgenerateavoltage
levelof+5to+15Vdc(logic“low”),and-5to-15Vdc(logic“high”)intoaloadof3to
7kΩ.AnRS-232receivermustpresenta3to7kΩload,convertinganinputof+3to
+25Vdctologic“low”,andaninputof+3to+25Vdctologic“high”.
Withapositivetriggerpulse,theoffsetvoltagedoesnothaveanysignicance.Even
smallvariations(utter)overandbelow0Vdcwillnottriggertheinterface.
Externalsynchronisationcableto9–pinD-connectorusinganRS-232interface
GROUND
RTS
CTS
GROUND
RTS
CTS
5
7
8
5
7
8
9-pinD-connector 9-pinD-connector
(CD016021-001)
RS-422serialinterfacescanalsobeusedforsynchronizationpurposes.InRS-422,the
voltagelevelsare+6Vdcand–6Vdc.Thepositivevoltageislogic“low”.Ingeneral
use,theadvantageofRS-422isthespeedandmaximumrange.Thesamepins(5,7and
8ona9–pinD-connector)areusedforsynchronization.
Important
WhenyouuseRS-422youmustkeepinmindthattheshiftfromlogic“low”tologic
“high”happensat0Vdc.Youroffsetvoltagemustthereforebenegativetopreventsmall
variations(utter)overandbelow0Vdctotriggertheinterface.
SU90setupasSlave
WhentheSU90issetupasaSlave,thesonarmustreceiveatriggersignalfromthe
synchronisationuniteachtimethesonarshallbepermittedtotransmit.Thistrigger
signalisinterfacedtothesonar'sserialport,wheretheCTS(ClearToSend)pinisused
togivetheoperatingsystemanEventmessage.TheEventmessageishandledbythe
software,anditwill(ifpreviouspinghasbeennished)startthepingsequence.
AsanacknowledgetothesynchronisationfromtheMasterunit,theSU90willlowerthe
RTS(ReadyToSend)beforetransmitting.ThisindicatesthattheSU90is“busy”.Once
thetransmissionandreceptionsequenceends,theSU90willraisetheRTS(ReadyTo
Send)toindicatethatitisreadyforthenextping.
SU90setupasMaster
WhensetupasaMaster,theSU90canbesetuptoignoreSlaveacknowledge.This
isknownasFreerunningmode.
138
381293/A