Hello @søren-hedegaard-0,
you didn't pass any input value to the ph_control_hourly(), so the block doesn't know anything about run_at_time and ph_hourly_feed.

The call should look this:

ph_control_hourly(run_at_time := local_run_at_time, ph_hourly_feed := local_ph_hourly_feed, out => local_out_value)

If you look in to the help (F1) of any built-in FB, you will see a usage and you learn how the ST works:

0_1562829190459_f0f1c9ad-8563-4baa-a5ee-d78b797fe4c4-image.png

Best regards,
Martin