Specifications

Maxiva ULX Series
November 11, 2013
4‐15
888‐2628‐300 WARNING:Disconnectprimarypowerpriortoservicing.
Copyright©2013,HarrisBroadcast
4.4.7 ControllerAreaNetwork(CAN)Bus
TheControllerAreaNetwork(CAN)busisahighspeedserialcommunicationslinkwhichisusedbetweenthe
transmittercontrolboardsfortransmissionofcontrol,status,faultandmeteringinfo rmation.TheCANbusis
distributedaspartoftheCabinetBusandSystemBus.TheCANbuscanoperateatspeeds
upto1Mbpsandis
designedtooperateinhostileindustrialenvironments.Thetransceiversfeaturecrosswire,lossofground,over
voltageandovertemperatureprotections.ACANtransceiverconnectedtotheCANbusisconsideredaNode.There
canbeupto110nodesonthebuswitha
maximumbuslengthofabout40metersfor1Mbpsoperation.
InaCANsystem,dataistransmittedandreceivedusingmessagefr ames.Messageframescarrydatafroma
transmittingnodetooneormorereceivingnodes.ThemessagestransmittedfromanynodeonaCANbusdonot
containaddressesofeitherthetransmittingnodeorofanyintendedreceivingnode.
Instead,thecontentofeachmessageframe(e.g.ON,OFF,PS1Voltage,CoolantFlowOKetc.)islabeledbyan
identifierthatisuniquethroughoutthenetwork.Allothernodesonthenetworkreceivethemessageandeach
performsanacceptancetestontheidentifiertodetermineifthemessage,
andthusitscontent,isrelevanttothat
particularnode.Ifthemessageisrelevant,itwillbeprocessed;otherwiseitisignored.
ThemicroprocessorsintheMCMandPCMboardshavebuiltinCANcontrollerswhichconnecttoaCANtransceiver
andbecomesanodeontheCANbus.TheCANtransceiverinterfacesthesingleendedCANcontrollertothe
differentialCANbusforhighcommonmodenoiseimmunity,asshownin
Figure4‐9.ThemasterandslaveTCUscan
sendandreceiveinformationoverthedifferentialCANbus,howevertheMCMcardinthemainTCUdetermines
whatinformationissentandwhenitissentforthisapplication.
Note
The MCM card (in the TCU) contains LED’s that will flicker on and off at a random rate indicating that
there is activity on the CAN bus. If the LED’s are off or always on, then the CAN bus is most likely not
communicating. The LED pair DS7 and DS8 are for the cabinet CAN bus (Rx & Tx respectively). LED’s
DS11 & DS12 are indicators for the system CAN bus (Rx & Tx respectively).
.
Figure 4-9 CAN Transceiver Diagram
Allfaultreporting,statusandmeteringinformationdisplayedontheGUIissentontheCANbustotheMCM.
TransmittercontrolsignalsarealsosentviaCANbutarealsosentoverhardwiredparallelcontrollines.
RemoteMetering Notavailableduetoweblossbutavailableonparallelremote. NO/YES
BasicParallelRemoteControl YES
BasicParallelStatusLines YES
ExciterParallelControl YES
ExciterSerial
Communications
YES
WebConnectivity NO
Table4‐9LifeSupportFunctionality
SystemFunction Description
AvailableinLife
SupportMode
1
8
7
6
5
4
3
2
Standby
Control
Reference
Voltage
Transmitter
Receiver
VREF
RXD
TXD
RS
CANH CANL
GND
VCC
TXD and RXD
connect to the
CAN controller
built into the
Micro Module
(Differential CAN Bus)