daughter father has weekend visitation but recently was found gulity of a charge so have to serve weekend jail time. what do i need to do

I would keep a journal of all visitation which is missed or that for which the child's father shows up late.  You may need the journal at a future child custody or visitation hearing.  As to the issue of a custody order "violation," your child's father is only violating the order if it states that he "shall" have the child every other weekend.  If the order states that he "may" or "will" have visitation every other weekend, the courts will not find that he has violated the order.  The visitation schedule is the maximum visitation he has with the child unless the two of you agree otherwise.  Either of you may be unailable for your visitation from time to time, but that doesn't rise to the level of a "violation."  I would contact my attorney about the conviction of the crime had anything to relation to crimes that would be harmful to children or a crime of dishonesty so your attorney has the information for any future hearings.