[PWM] Pulse width modulation

Function block PWM converts an analog value to a time-based alternating discrete value.

PWM converts an analog value to a time-based alternating discrete value.

Functioning

PWM converts an analog value to a time-based alternating discrete value. The duration during which the output [Out] stays with the value True or False depends on the block’s time configuration and the current value at input [In]. The duration for the value True at the output [Out] is proportional to the value at input [In].

Time [TiOnMin] defines the required minimum on-time for the output after it is switched on. Time [TiOffMin] defines the required minimum off-time for the output after it is switched off. The value at [TiPrd] must be greater than 0 for the block to start operating. If the sum of [TiOffMin] and [TiOnMin] is greater than [TiPrd], then the minimum on-time is adjusted as follows: [TiOnMin] = [TiPrd] – [TiOffMin]. If [TiOffMin] is greater than [TiPrd], then the configured values at [TiOffMin] and [TiOnMin] are ignored.

The values configured at [TiOffMin] and [TiOnMin] define the minimum and maximum valid values for input [In]. Values at input [In] below the minimum valid value are interpreted as 0%. Values at input [In] above the maximum valid value are interpreted as 100%.

Pins

Input

Description

Data type

Default value
Value range

EnFnct

Enable function

Boolean

1

0 - The PWM function is not enabled.
1 - The PWM function is enabled.

In

Input

Input value

Real

0.0
0.0...100.0

TiPrd

Time period

Time period of the PMW algorithm

Time

30M
0S...1D

TiOnMin

Minimum switch-on time

Minimum on-time for the output

Time

0S
0S...1D

TiOffMin

Minimum switch-off time

Minimum off-time for the output

Time

0S
0S...1D

 

Output

Description

Data type

Default value
Value range

Out

Output

Boolean

0

Application

PWM can be used as an alternative to the PWM BACnet extension functionality, available for some of the output objects.