This refers to a piece of equipment that has been requested to do a certain task but the indications coming back show that it has not performed that task.
It is often used in reference to points, as in points that were requested to be controlled normal but are not detected normal, or controlled reverse but not detected reverse. Each time a point moves there will be a period of a few seconds whilst the point blades move where the point detection and point controls do not match, i.e. correspond.
Last edited by GeoffM on 15/09/2016 at 03:01