24 hour delay ? is this correct

[Nigel Goodwin]

One point that seems to be forgotten is that the internal oscillator is factory calibrated only to an accuracy of +/- 1%, which amounts to about +/- 14 minutes over the course of a day. You may try to improve this by modifying the contents of OSSCAL, but I'm not sure what resolution can be obtained using the OSSCal register. I think in order to obtain better accuracy it will be necessary to tune the program by trial and error by varying the nominal time delay from 86400 seconds. The frequency of the internal oscillator will still vary with changing temperature, and an external crystal will be more stable. Of course, the crystal will takeup two pins of an already limited resource. Crystals typically have a stated accuracy of 50 ppm so it may be necessary to tune the program even when using a crystal.

Has he ever suggested he's using the internal oscillator?, I've never noticed he had?.

 

[skyhawk]

Has he ever suggested he's using the internal oscillator?, I've never noticed he had?.

It was an assumption on my part. Maybe the OP will be kind enough to tell us whether he intended to use a crystal.

 

[Darkstar64]

Thanks guys all give this all a try and yes im using the iinternal oscillator and know that it won't be 100% accurate it really doesn't need to be as long as its around the same time everyday not like 14 min late this day then 28 the next day and so on as long as it goes off around the same time everyday it should be fine

 

[blueroomelectronics]

The error will accumulate over time and temperature. It's about 1% at room temperature but it won't take long before it appears to drift. Use a crystal they're only a $1 or so.

 

[Darkstar64]

Ok thanks all let me teacher know that I had a better Idea but he said to use just use delay's on the PIC but all tell him that I was right and he was wrong haha thanks alot guys