5 Function blocks
5.20 LS, value scaling
216 Control Relay easy800 11/11 MN04902001Z-EN www.eaton.com
Figure 154:Function block value scaling - increasing value range
a Source range
b Destination range
The mathematical relationship is follows:
• Y = m x X + Y0
• m = (Y2 - Y1) / (X2 - X1)
• Y0 = ((X2 x Y1) - (X1 x Y2)) / (X2 - X1)
m = gradient
Y0 = Y offset when X = 0
X1, Y1 = First value pair
X2, Y2 = Second value pair
g = Straight line with positive gradient
Figure 155:Mathematical interrelationship
Application example
The signal of measuring value converters with a current output reaches the
input LS..I1 of the scaling function block via the output of a multiplexer
function block. The measuring value is between:
• 4 mA, corresponds to measured value 0 and
• 20 mA, corresponds to maximum measured value.
Memory
64 + per 4 Byte/Constant at function block input
Cycle time [μs]
easy800 standard easy800-SWD
224 98
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