Can't change a value through PHP

Hi. I've read some post on this site about replacing value in form. But using php, I can not do it.

I've made teaxtarea with id dopinfo and with the same name. In the setup tab I've added the php block with code:

<?php
$this->data['dopinfo'] = "dfhfbcvbcv fgh fghfgh fghfgh fgh f";
?>

but textarea is still empty on load.
Replacing $this with $form does not help.
Version of chronoforms is 6

What am I doing wrong?

[URL=https://savepice.ru/][IMG]https://cdn1.savepice.ru/uploads/2017/11/26/2fe6a3f9d0297d80cd5e1274c2583136-full.jpg[/IMG][/URL]

yes, thank you, I already guessed🙂