GE T2100 - RS-232;422 Interfaces; ESD and EMI Compatibility; Isolation; Operation

TheoryofOperation
RS-232/422Interfaces
TheLTC1334servesastheHosttoIFCboardtransceiver.IttranslatestheRS422/232
serialprotocolvoltagelevelstoTTLlevels.TheMAX489isthetransceiverforthe
processorboardtodrivecommunication.IttranslatesRS422signalstoproperTTL
levels.
ESDandEMICompatibility
Theconnectorsonthisboardhavecurrentlimitingresistorsandlteringcapacitorson
almosteverysignaltopreventEMIfromescapingthisboard.Thesecomponentsalso
limitrise-timeandvoltageswhichmaycomefromESDorothernoisesources.
Isolation
Thedriveserialcommunicationcircuit,drive,andelevationcontrolsignalssharea
commongroundthatmaybeattachedtothechassis.TheHostserialcommunication,
ESTOPconnection,calibrationbutton,andcontrolcircuitryareallplacedonisolated
power.Thisgroundallocationseparatesthemicrocontrollergroundfromthechassis
groundbyusingopto-couplersallowingatleast4KVACwithoutbreakdownand
doubleisolationfor250VAC.
Operation
Theprocessorboard’smaintaskistomonitortheproperT2100Treadmilloperationby
testingselectedvariablesfromthesystem.Incaseofanyvariableoperatingoutof
specs,thermwarewillrstdetecttheevent,thenlogit,andnallystopanyfurther
operation.Forspeedcontrol,theprocessorboardwillactasatranslatorbetweenthe
hostandthedrivesystem.Forelevationcontrol,theboardwillactasacontroller
byprovidingpropercalibrationandbyhandlingelevationincrement/decrement
commandsreceivedviathehostserialport.
Start-UpSequence
Immediatelyafterpower-up,theprocessorboardwillstartaself-testprocedure
wherethefollowingsubsystemsaretested:internalRAM,boardtemperature,external
serialashmemory,hostcommunication,drivecommunication,controlsignals,
elevation,powersupply,ESTOP,andcalibration.Ifanyoftheabovetestsresultinan
abnormalcondition,theprocessorboardwillstopanyfurtheroperationandwilllog
theconditiononitsexternalashmemory.Afterallsubsystemsaredeterminedto
beoperatingproperly,theprocessorboardwillenterinastandbystateuntilaserial
commandisreceivedfromthehost.Theprocessorboardwillwaituntilthehost
sendsabeltstartcommand"B<CR>"tostartoperations.Afterreceivingthebeltstart
command,theboardwillenablethedrivebyactivatingtheD_DRIVE_ENsignalonJ2.
Afterthisaction,thedrivewillbeactivatedandinstandbystate.Atthismoment
elevationandspeedcontrolcommandscanbesenttotheprocessorboard.
ElevationControl
Theelevationcontrolprocessworksasfollows:Thehostwillsendanelevation
command"GXXX0<CR>"totheprocessorboard,themicrocontrollerwillinterpretthis
datainordertoenabletheelevationsubsystembyassertingEN_ELEVsignalonJ9and,
basedontheactualelevationstatus,assert/de-asserttheUP/DOWN*signalonJ9
untiltherequestedelevationisachieved.Theelevationrangeisfrom0to25%grade.
2021403-120F
T2100Treadmill
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