Patent SG-174690-A1 (SG)
Title: Communication control method, communication control program and master communication system
Inventor: YOHEI FUKUMOTO
Filed: 2011-03-09
Abstract: OF THE DISCLOSUREA communica on control method of a master-slavecommunication s tern which is configured in such a manner that5 a plurality of sl e communication devices are connected to a master communicatio system through a communication network, in which the master co unication system repeatedly executes: communication device as Ignment processing that the master communication system assl ns one slave communication devicelo among the plurality of the save communication devices; query transmission processing that ansmits a query to the assigned slave communication device; and esponse reception processing that receives a response from the slave communication device to which the query is transmitted, s a series of a15 communication processing unit. The ster communicationsystem comprises: a timeout error monito ng timer that detects whether or not the response to the trans itted query isreceived; and a timeout error counter that unts a number of detections of successive timeout errors for e h of the slave20 communication devices. In the response recepti processing,when the response is received from the slave co nication device assigned in the communication device assign entprocessing, the master communication system executes a tep of resetting a count value of the timeout error counter25 corresponding to the slave communication device to zero, n when a timeout error is detected based on a notification fr the t meout error monitoring timer, the master communication system xecutes steps of: increasing the count value of the timeout e ror counter corresponding to the slave communication device by o e; terminating the communication processing unit5 immediately; tetermining whether or not a count value of the error counter rr.ached a predetermined count value, while terminating the ci unication processing unit; and outputting error information i dicating that the slave communication device is in failure •f the count value of the error counter COMMUNICATION CONTROL METHOD, COMMUNICATION CONTROL PROGRAM AND MASTER COMMUNICATION SYSTEM OF THE DISCLOSUREA master communication system 2 repeatedly executes assigning one of slave communication devices 4, transmittinga query to the assigned slave communication device 4 and10 receiving a response to the query, as a series of acommunication processing unit. The master communication system 2 includes a timeout error counter 24 for counting a number of times that failed to receive the response for each of the slave communication devices, and when the response to15 the transmitted query is received, resets a count value of the timeout error counter, and when failed to receive the response within a predetermined time, increases the count value of the timeout error counter 24, while terminating the communication processing unit, and if the count value of the timeout error20 counter 24 reached the predetermined count vale, the master communication system 2 determines that the slave communication device is in failure (permanent error).Fig. 1