A deliberative vote is held by all members of a representative body. The position of chair (or president or speaker) has the same single vote as other members. If the votes are tied then the motion is determined in the negative.
Reference: Section 23 of the Commonwealth Constitution: Questions arising in the Senate shall be determined by a majority of votes, and each senator shall have one vote. The President shall in all cases be entitled to a vote; and when the votes are equal the question shall pass in the negative.