Fault detection device for encoder wiring

A fault detection device which detects a fault having occurred in encoder wiring in a system including a controlled apparatus having an encoder and a controller controlling the controlled apparatus and, in the system, the encoder and the controller being connected with each other through the encoder wiring,

• in a case that a signal which is transmitted from the encoder to the controller is defined as a first signal, and a signal which is transmitted from the controller to the encoder is defined as a second signal, the fault detection device comprising:
• a first detection circuit which detects a fault in the encoder wiring through which the first signal is transmitted from the encoder to the controller;
• a second detection circuit which detects a fault in the encoder wiring through which the second signal is transmitted from the controller to the encoder, wherein the second detection circuit is provided in the controlled apparatus;
• and
• an interface part provided in the controlled apparatus, wherein the encoder wiring is divided into interface wiring between the controller and the interface part and in-apparatus wiring between the interface part and the encoder, the interface part comprises:
• a first receiver which receives the first signal through the in-apparatus wiring,
• a first driver which transmits the first signal through the interface wiring based on a received result in the first receiver,
• a second receiver which receives the second signal through the interface wiring, and
• a second driver which transmits the second signal through the in-apparatus wiring based on a received result in the second receiver,
• the first detection circuit is provided on an input side of the first receiver in the interface part, and
• the second detection circuit is provided on an input side of the second receiver in the interface part.