As you can see, I'm new to this.
Since I'm using Pic Basic Pro, I use ADCIN and sampleus time
What I want is to get ADCIN 0 each time required for the program (velocitiy), and ADCIN 1 and ADCIN 2 each two seconds alternatively, because they are temperature measurements that I don't need in a shorter frecuency, so I would preffer to have ADC in a mode that don't use procesor time. I was thinking on something like @ ADCON0.1=0 (go/done bit) to stop it when no needed, and start it again later, but then I was asking myself if the ADC simple works without interfering with the rest of the program when I don't use ADCIN. I don't know. I hope somebody knows that.

The original though was that the sampleus time could determine this 2 second periods alternated, 4 seconds each, although I think now that sampleus can be short and the time to get the readings be determined by program as the example below.

My concernings are two:
1. The ADC could use a lot of procesor time or worst: that it breaks the USB connection I'll have
2. That a big sampleus time be the one taking the procesor time

---------------------------------
' THIS TAKES TIME FROM TICS ONLY FIRST TIME
if banderaTpoini=0 then ' bit solo la primera vez toma tiempo
tpoini=centesimas1 ' word
banderaTpoini=1
endif

' THIS ADD THE TIME BETWEEN READINGS
if banderaSumarRet=0 then ' bit, suma retardo para tomar temperatura
activarADTemp = retardoTomarTemp + tpoini 'word
endif

' IF OVERFLOW COUNTER
suma= activarADTemp ' word, ComparaT
if suma >= maxT1 then ' 4000 sobrado para tmpos máq. una v. Word
activarADTemp= suma - maxT1 '
endif

'---------------------------------------------
' En declaraciones
temp=0 ' bit
dejar un define sampleus chico, tal vez 100

' IF TIME NOW, ALTERNATE READINGS
if centesimas1>= activarADTemp then
if temp=0 then
temp=1
ADCIN1 ' HERE READING AND MORE CODE
else
temp=0
ADCIN2 ' HERE READING AND MORE CODE
endif
tpoini= centesimas1
banderaSumarRet=0
' ¿Apaga AD Go/done? Sería con @ ADCON0.1=0 y reponerlo antes de ADCIN 'HERE SHUT DOWN ADC
' I WOULD PUT IT ON BEFORE READING
endif

THANK YOU VERY MUCH FOR YOUR COMMENTS