Rievtech xLogic ELC Series - Page 143

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Parameter p (number of decimals)
Parameter p applies only to the display of the Ax value in a message text.
Description of the function
The function reads the value of the signal at the analog input Ax.
This value is multiplied by the value of parameter A (gain). Parameter B (offset) is added to the product,
as follows:
(Ax * Gain) + Offset = Actual value Ax
The function block calculates the proportion of the value Ax to the range. The block sets the digital output
Q high for the same proportion of the PT (periodic time) parameter, and sets Q low for the remainder of
the time period.
Examples with Timing Diagrams
The following examples show how the PWM instruction modulates a digital output signal from the analog
input value:
Example 1
Analog input value: 500 (range 0...1000)
Periodic time T: 4 seconds
The digital output of the PWM function is 2 seconds high, 2 seconds low, 2 seconds high, 2 seconds low
and continues in that pattern as long as parameter "En" = high.
Example 2
Analog input value: 300 (range 0...1000)
Periodic time T: 10 seconds
The digital output of the PWM function is 3 seconds high, 7 seconds low, 3 seconds high, 7 seconds low
and continues in that pattern as long as parameter "En" = high.