How to get my nikon d40 timers to stay on for long periods?

I can get it stay on for about 1 min, but manual says it can be changed on page 33… No it don't.
any help, thanks.

Added (1). I'm waiting for owl's to return to a small barn, not really enough room for me, easily seen. I want to sit out the way but leave the camera there.

Added (2). Sorry to take pic's with remote sensor

Added (3). There's only one beam for it to sit on, away from the nest box. So I was going to set it up focusing on that beam. I will be operating it manually when it returns. It say's remote can be set for upto 15 mins, but I can't find that either. Thanks again for any help.

Added (4). There's only one beam for it to sit on, away from the nest box. So I was going to set it up focusing on that beam. I will be operating it manually when it returns. It say's remote can be set for upto 15 mins, but I can't find that either. Thanks again for any help.

Added (5). Fhotoace that's exactly what I want to do. But I can't find the setting on my camera to set it to 30 mins or longer.been throught the manual but the settings don't come up! Sometimes in can sit for hours, so I don't want to be up and down resetting it.

You don't understand the concept of using a remote shutter release and what is meant by using a remote to hold the shutter open. This only happens when your camera is in the bulb setting.

For now do this.

* Attach your camera to the one beam
* Take a good light meter reading on the nest box and use those settings in the manual mode
* Prefocus the lens on the nest of the owl (manual)
* Sit at in your hidden spot in the barn and physically press the remote shutter release each time the bird returns to its nest box.

What are you trying to do? Long exposures or timelapses or what?

Edit

Check pages 78/79 of the manual, link.

If the camera is in manual focus and manual exposure mode, you probably only need to keep activating the camera every 15 minutes or so when using a remote. Are you using the appearance of the owl to trigger the camera or are you using a remote release and hoping for the best?

A further edit…

So the basic issue is that you can't override the camera's auto-turn-off after whatever time interval. The downside of electronics. You could try a device such as the CameraAxe, link 2, that does all sorts of things. It would be best to contact them directly to check if it has a facility to keep waking the camera up after a certain time interval. Though, obviously you may run out of battery life if, effectively, the camera's on permanently.

You're confusing your timers! See pages 78 and 79. On page 79, it shows how to adjust the "remote on duration" (item 17). You can set the remote on duration to a maximum of 15 minutes.

If you want to prolong the timer beyond 15 minutes, take a picture at least every 10 minutes and it will reset the timer. Just be sure your critter isn't nearby so you don't spook it with the shutter noise. Taking a picture without your subject isn't a big deal since "film" is free.

If you can't find the remote on duration timer, you need to look at page 74 in your manual. You must set up your CSM/Setup menu to "FULL" so it will show all the options. If you have simple or custom menus selected, you will/might not see the remote on duration selection.