6. Function blocks6.1 Manufacturer function blocks6.1.3.4 LS - Value scalingGeneraleasyE4 base devices provider 32 value scaling function blocks,LS01 through LS32.These function blocks can be used to transfer values from onevalue range to another. More specifically, a value scaling func-tion block will take one of the mathematical relationships youhave specified and use it to scale the value at input LS..I1 inorder to then output it, either as smaller value or larger value,at output LS..QV. The mathematical relationship is based on astraight line defined by the coordinate pairs X1, Y1 and X2, Y2(see under “The mathematical relationship is:”).A typical application is the conversion of values, such as0…20 mA to 4…20 mA. An easy800 device is provided with32 value scaling function blocks.Operating principle"EN = 1" starts the function block."EN = 0" initiates a reset in which the output QV is reset to 0.Figure 143: Figure: Scaling the input values - reducing Source rangeDestination rangeFigure 144: Figure: Scaling the input values - increasingThe mathematical relationship is follows:m = GradientY0 = Y offset when X = 0X1, Y1 = First value paireasyE4 11/18 MN050009 EN www.eaton.com 259
