Measure the size of sagging of a cable. If the result of measurement exceeds the limit of the admissible range (1.0 ÷ 3.0 mm), release a lock nut and make the corresponding adjustment by rotation of an adjusting nut.
Do not forget to tighten after performance of adjustment a lock nut with the required effort (15.7 ÷ 22.5 Nanometers).