Robert: กกก PROBLEM SOLVED กกก
The power supply is 5 V. I am checking Portb.7 because I config the DACCON0 as $90.
This enable the DAC and select Portb.7 as output.
I move the DACCON0 register as you suggest,but the result is the same.
Also I do not why,PORTA.6 remains lit when is making the voltage loop.
It is configured as output and I clear the port at the begginning.
I am using the EASYPIC V7 for development,and I realize I was loading
The portb with the panel Leds. I turnoff the led selection and now all is working OK.

Thanks for your comments...
Ruben de la Pena