Owing to the fact that the absolute encoder `wraps' at a certain point, it is very important to zeroset the incremental encoder against the absolute at a known physical position. That position is mount PA 180, and it is the `park' position for INTEGRAL. When the rotator is at this position the `180' label marked on the rotator in indelible ink is at the 12 `O' Clock position when viewed from the GHRIL bench. Before observing with INTEGRAL it is important to ensure that the rotator is in this position (to within twenty degrees or so is adequate). The local controls can be used to move it if necessary. The incremental encoder can then be zeroset against the absolute in the usual way. It must not be zeroset without a visual check that the rotator is in the required position.