Star Trek

In a season 1 episode 114 entitled "11001001" Picard and Ricker set the self destruct sequence. They made a comment about how the duration of the countdown is set by the computer and there is no choice. But in season 2 episode 2 entitled "Where Silence Has Lease" Picard decided to again set the self destruct sequence, this time however they talk about how long they should set the timer for and decide on 20 minutes. Was this ever explained or what was used later on in the show for self destruct?

I am not sure on that one to be fair but they made of been a re-fit in between Season 1 and 2 to change the processes of self destruct seeing as riker loves it so much when he is in command

i guess that could be possible but there was 0 mention of it and since i am watching them in order again right now i would have noticed... lol

The self-destruct mechanism in the NCC-1701 Enterprise would only give a 1 minute countdown as shown in Star Trek III. lol

I think that maybe there is a default, unless you specify otherwise.

Is there some way to stop it, if you change your mind?

You can stop it verbally or by inputting the codes. It seems like they didnt really have a streamlined system for the writers to follow. in some cases it took 3 officers to activate, 2 in some cases and in a few just the captain.