[phenixbb] an atom moves away during model refinement

Dear colleagues, While refining my model, the Mg atom for some of the margin units moves far away from them. I am also using the ELBOW files of Mg during the refinement. What is the way to restrict the movement of atoms during refinement? I found that this behaviour can be observed after simulated annealing is on. And the harmonic_restraints may be acquired to restrict atom movement. Is that right? I am using the GUI version of Phenix, and I cannot see those parameters. Thank you. Sincerely, Dmitry