Method of locating fault of communication system

A communication system, comprising:

• a loop data transmission channel for transmitting frames;
• a plurality of stations connected to said loop data transmission channel;
• at least one control station connected to said loop data transmission channel;
• and
• a plurality of host apparatuses connected to said plurality of stations and said control station;
• wherein each of said stations and said control station comprises:
• means for detecting lack of a reception signal received from said loop data transmission channel, and
• first reconfiguration means for estimating a fault location according to a position where said reception signal is lacking and reconfiguring said loop data transmission channel so as to avoid said fault location, and
• wherein said control station further comprises:
• means for transmitting a confirmation frame to said loop data transmission channel after said loop data transmission channel has been reconfigured by said first reconfiguration means,
• determining means for determining whether or not said fault location has been eliminated based on a response frame in response to said confirmation frame, and
• second reconfiguration means for giving the stations instructions to reconfigure the loop data transmission channel which has been reconfigured by said first reconfiguration means, when said determining means has determined that said fault location has not yet been eliminated,
• wherein said second reconfiguration means transmits a confirmation frame to the reconfigured loop data transmission channel and determining whether or not a normal response frame of each of said stations is present in response to said confirmation frame to determine whether said fault location has been eliminated, and provides instructions to the stations to reconfigure the loop data transmission channel until the fault location is eliminated when it is determined that the fault location has not yet been eliminated, and
• wherein each of said plurality of stations further comprise:
• means for confirming the normality of said confirmation frame received from said loop data transmission channel,
• means for transmitting the response frame in response to said confirmation frame to said loop data transmission channel when said received confirmation frame is normal, and
• means for changing said loop data transmission channel configuration according to the reconfiguration instructions from said second reconfiguration means, received via said loop data transmission channel,
• wherein said host apparatuses connected to said control station comprises:
• means for determining whether or not the fault location has been eliminated by exchanging messages between said host apparatuses by using frames after the configuration of said loop data transmission channel has been changed in accordance with the reconfiguration instructions from said second reconfiguration means, and
• third reconfiguration means for exchanging messages between the host apparatuses by using frames to determine the fault location and providing the reconfiguring instructions to the other host apparatuses so as to reconfigure the loop data transmission channel to avoid the detected fault location when it is determined that said fault location has not yet been eliminated.