2 HARDWARE ARCHITECTUREThe main components comprising devices based on the Px4x platform are as follows:● The housing, consisting of a front panel and connections at the rear● The Main processor module consisting of the main CPU (Central Processing Unit), memory and aninterface to the front panel HMI (Human Machine Interface)● A selection of plug-in boards and modules with presentation at the rear for the power supply,communication functions, digital I/O, analogue inputs, and time synchronisation connectivityAll boards and modules are connected by a parallel data and address bus, which allows the processormodule to send and receive information to and from the other modules as required. There is also a separateserial data bus for conveying sampled data from the input module to the CPU. These parallel and serialdatabuses are shown as a single interconnection module in the following figure, which shows typicalmodules and the flow of data between them.CommunicationsAnalogue InputsI/OInterconnectionOutput relay boardsOpto-input boardsCTsVTsRS485 modulesEthernet modulesKeypadLCDLEDsFront portWatchdog modulePSU moduleWatchdogcontacts+ LEDAuxiliarySupplyIRIG-B moduleProcessor moduleFront panel HMI Output relay contactsDigital inputsPower system currentsPower system voltagesRS485 communicationTime synchronisationEthernet communicationV00233Note: Not all modules are applicable to all productsMemoryFlash memory for settingsBattery-backed SRAMfor recordsFigure 2: Hardware architectureChapter 3 - Hardware Design MiCOM P74726 P747-TM-EN-1
