Quote Originally Posted by mister_e
How far your SHT sensor is?
Is your board send the voltage to your sensor?
How? i mean, is there any buffer between your PCB and your sensor? case not, it's one other possibility of noise source.
sht cable sheild length 3m.
sht supplied +5v from my PCB without any buffer,and how can i put this buffer ,can you explain more.

Quote Originally Posted by Melanie
Is it because noise on the line is causing the chip to acknowledge at the wrong time or send garbage
i tracked the problem and i found the problem from noise on the line , i tried to replace the sht cable with short one (0.5m) and the noise is cancled >.

SO . can i run timer on the first sht code and stop it on the end of code , if the timer reached to the maximum time then reset the pic .

Quote Originally Posted by Melanie
Make sure the Battery isn't next to a contactor switcing kVA - the usual things...
should i connect battary to ds1307 , in my pcb i connect battary pin to ground . is this the problem .