What happens to an Artillerist artificer's Eldritch Cannon if the Artillerist falls unconscious?

Question

What happens to an Artillerist artificer's Eldritch Cannon if the Artillerist falls unconscious?

The Eldritch Cannon is a magical object created by an Artillerist artificer (E:RftlW p. 59, TCoE p. 17; emphasis mine):

The cannon is a magical object. Regardless of size, the cannon has an AC of 18 and a number of hit points equal to five times your artificer level. It is immune to poison damage and psychic damage. If it is forced to make an ability check or a saving throw, treat all its ability scores as 10 (+0). If the mending spell is cast on it, it regains 2d6 hit points. It disappears if it is reduced to 0 hit points or after 1 hour. You can dismiss it early as an action.

The three options given for the cannon disappearing are:

• Cannon HP = 0
• 1 hour has passed
• Dismissed as an action

So presumably the Artillerist falling to 0 HP doesn't affect the cannon; it will remain but will be inactive until the Artillerist has been revived. Is this interpretation correct?

Answer 1

It disappears 1 hour after it was created, or when it is reduced to 0 hit points.

You have emphasized the relevant rules text:

It disappears if it is reduced to 0 hit points or after 1 hour. You can dismiss it early as an action.

Nowhere is the cannon's existence tied to the Artificer's consciousness, so falling unconscious doesn't change anything about the cannon - it persists unless it is reduced to zero hit points or its 1 hour timer expires.

Answer 2

You are correct: the Eldritch Cannon stays around.

As stated in the quote you gave, the cannon only disappears if it runs out of HP or time, or if you actively dismiss it. If you fall unconscious or even die, there is no rule that says the cannon would disappear, so it doesn't.

The next line answers the rest of your question:

On each of your turns, you can take a bonus action to cause the cannon to activate if you are within 60 feet of it.

Since the cannon only does anything if you use a bonus action to activate it, if you can't take bonus actions, it just sits there and waits.