According to the Exec binding wiki, you only have access to the current item’s current state or command, not a different item’s. But if you used the Abus_Motion_timer_sec item for the exec binding, you could achieve what you’re after:
Number Abus_Motion_timer_sec "your label [%d]" (G_Abus) { exec=">[*:curl http://root:xxxx@192.168.178.23:8080/cgi-bin/admin/setparam.cgi?event_i0_delay=%2$s]" ...optional additional binding configs separated with commas... }
In other words, sending number commands to your Number item will cause the number in the command to be sent to the web server.
I am sorry, but both solutions did not help.
The first syntax (@Mikey) is refused by OH Designer.
The second (@watou) doesn’t throw an error, but the website is not updated.
(no error in the log).