An objective is to obtain a high robust position controller and a controlling method therefor, with respect to their technique in which control gain, in order to prevent an overshoot due to frictions, is most suitably adjusted. In one embodiment, the ratio of arginine to is assessed to aid in diagnosis. The non-polymeric silica scale control additive retards deposition of silica scale in the subterranean formation. The glazing system also includes an elastically deformable washer positioned between each fastener head and the impact glazing.