Encoder

A sealed encoder module for mounting onto a machine so as to measure relative displacement of first and second parts of the machine, the sealed encoder module comprising, a scale, a readhead comprising a scale signal receiver, and an integral protective housing which encapsulates at least the scale and said scale signal receiver, wherein the sealed encoder module is configured to determine and output diagnostic information regarding a scale signal detected by the readhead.

A sealed encoder module for mounting onto a machine so as to measure relative displacement of first and second parts of the machine, the sealed encoder module comprising, a scale, a readhead comprising a scale signal receiver, and a protective housing which encapsulates at least the scale and said scale signal receiver, in which the scale signal receiver comprises an outer case within which the scale signal receiver's electronics that are located inside the protective housing are contained and protected from contamination that enters the sealed encoder module's protective housing.

A sealed encoder module for mounting onto a machine so as to measure relative displacement of first and second parts of the machine in a first degree of freedom, the sealed encoder module comprising, a scale, a readhead comprising a scale signal receiver, and an integral protective housing which encapsulates at least the scale and said scale signal receiver, wherein the sealed encoder module is configured to determine and output diagnostic information regarding the positional relationship of the scale and the scale signal receiver in at least one degree of freedom other than the first degree of freedom.

A method of setting up a sealed encoder module for measuring the relative position of two relatively moveable parts of a machine in a first degree of freedom, the sealed encoder module comprising, a scale, a readhead comprising a scale signal receiver, and an integral protective housing which encapsulates at least the scale and said scale signal receiver, wherein the sealed encoder module is configured to determine and output diagnostic information, the method comprising using said diagnostic information to determine whether the scale and the scale signal receiver are in a desired relative positional relationship in at least one degree of freedom other than the first degree of freedom.