125
125
125
125
Parameter
Parameter
Parameter
Parameter PT
PT
PT
PT
The periodic time PT can be provided by the actual value of another already-programmed
function:
Analog comparator: Ax – Ay
Analog trigger: Ax
Analog amplifier: Ax
Analog multiplexer: AQ
Analog ramp: AQ
PI controller:AQ
Analog math: AQ
Data latching relay: AQ
Up/Down counter: Cnt
Parameter
Parameter
Parameter
Parameter p
p
p
p (number
(number
(number
(number of
of
of
of decimals)
decimals)
decimals)
decimals)
Parameter p applies only to the display of the Ax value in a message text.
Description
Description
Description
Description of
of
of
of the
the
the
the function
function
function
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
Examples
Examples
Examples with
with
with
with Timing
Timing
Timing
Timing Diagrams
Diagrams
Diagrams
Diagrams
The following examples show how the PWM instruction modulates a digital output signal from
the analog input value:
Example
Example
Example
Example 1
1
1
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
Example
Example
Example 2
2
2
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.
Calculation
Calculation
Calculation
Calculation rule
rule
rule
rule
Q = 1, for (Ax – Min) / (Max – Min) of time period PT
Summary of Contents for xLogic
Page 1: ......
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Page 102: ...100 100 100 100 B B B B Blocks Blocks Blocks Blocks...
Page 105: ...103 103 103 103 G G G G M M M M status status status status...
Page 106: ...104 104 104 104 H H H H AM AM AM AM value value value value...
Page 164: ...162 162 162 162 If the Memory Read block had been triggered the Q1 of ELC 12 CPU will be set 1...
Page 204: ...202 202 202 202 Step Step Step Step 6 6 6 6 Moving Moving Moving Moving...
Page 226: ...224 224 224 224...