Hi all,
even if I'm dealing with ethercat since more than one year, I'm in front
of a very basic question ...
As from I can see, the data in master->slave direction in the domain_pd
area are not preserved from an update to another.
I'mean that I need to write out data to domain_pd area at each cycle,
even if I data is not changed and theoretically I don't need to update
some parts of the pdo area.
Just applying this to the basic example in examples/user
void cyclic_task()
{
int i;
// receive process data
ecrt_master_receive(master);
ecrt_domain_process(domain1);
// check process data state (optional)
check_domain1_state();
if (counter) {
counter--;
} else { // do this at 1 Hz
counter = FREQUENCY;
// calculate new process data
blink = !blink;
}
EC_WRITE_U8(domain1_pd + off_dig_out, blink ? 0x06 : 0x09);
// send process data
ecrt_domain_queue(domain1);
ecrt_master_send(master);
}
moving the EC_WRITE_U8 inside the if condition (after the blink=!blink)
will not work, because the blink bit is cleared from the pdo area after
the process data has been sent.
This means that I should keep a copy of the process data and write it on
the domain1_pd each time.
Is this right or I'm missing something ?
Thanks,
Thomas.
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