Commerciallyavailablepower supply24VInternal supply power (5V)passes through the bus ofthe backplane to each unit.Power goes from a commercially availablepower supply to each I/O unit.FP2/FP2SHOverview1 − 121.2 Unit Types and Combinations1.2.2.2 Limitations on Current ConsumptionPower supply unit Rated current (at 5V)FP2−PSA1 2.5AFP2−PSA2 2.5AFP2−PSA3 5AFP2−PSD2 5AInternal supply power (5V DC)The 5V DC power used for driving the internal circuit of each unit is supplied from thepower supply unit through the internal bus of the backplane.External supply power (24V DC)The 24V DC power supply used as the input power supply of the input units and theoutput circuit driving power of the output units are supplied from the external terminalof each unit.For 24V power supply, commercially available power supply equipment is used.Combining units and selecting a backplaneThe current consumed by each unit is shown in the following pages.Give consideration to the combination of units so that the rated capacity of 5V DC and24V DC power supplies should not exceeded.Example of current consumption calculationThe table below shows the combination of typical units on a 9-module type backplane.Type Number of units andbackplane usedCurrent consumption at5V DC (mA)Current consumption at24V DC (mA)CPU (FP2−C1) 1 410 0Backplane (FP2−BP09) 1 60 0Input unit (FP2−X16D2) 3 60×3=180 8×16×3 = 384Output unit (FP2−Y16R) 4 120×4=480 160×4=640Total current consumption 1130 1024
