12.5.3 SFC 225 - HF_PWM - HF pulse duration modulation
This block serves the parameterization of the pulse duration modulation for the last two
output channels. This block is function identical to SFC 223. Instead of TIMEBASE and
PERIOD, the SFC 225 works with a predefined frequency (up to 50kHz).
Please note that this block is not part of the library for the Siemens TIA
Portal.
Parameters
Parameter Declaration Type Description
CHANNEL IN INT Number of the output channel for HF-PWM
ENABLE IN BOOL Start bit of the job
FREQUENCE IN WORD Frequency of the HF-PWM
DUTY IN DINT Pulse duty ratio per mille
MINLEN IN DINT Minimum pulse duration
RET_VAL OUT WORD Return value (0 = OK)
You define a time base, a period, the pulse duty ratio and min. pulse length. The
CPU determines a pulse series with an according pulse/break relation and issues
this via the according output channel.
ð
The SFC returns a certain error code. You can see the concerning error mes-
sages in the table at the following page. The PWM parameters have the fol-
lowing relationship:
Period length = 1 / frequency
Pulse length = (period length / 1000) x pulse duty ratio
Pulse break = period length - pulse length
Description
VIPA SPEED7
Device Specific
Onboard I/O System 100V > SFC 225 - HF_PWM - HF pulse duration modulation
HB00 | OPL_SP7 | Operation list | en | 18-30 285
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