| 摘要 |
PURPOSE:To reduce the waste of time and to shorten the data collection time by variably setting a maximum monitor time of wait for response to polling in accordance with the communication error rate of the system. CONSTITUTION:The communication error rate is used as a system parameter, and the polling response monitor time of a main station M or sub-main stations SM1 to SM3 is made proportional to the communication error rate, or a maximum frequency in retry for error of communication between two stations is made proportional to the communication error rate, or the main station totalizes the frequency in communication and the frequency in communication error of the system at intervals of a prescribed period to obtain the latest communication error rate and updates the communication error rate set in each station. Thus, the no-response monitor time is omitted when polling is performed by the main station M or sub-main stations SM1 to SM3 while being repeated by plural stations, and the total time required to collect data by systematic retry is shortened in the case of a failure of data collection due to no response. |
