Data collection device, data collection system, data server, data collection method, and non-transitory computer readable storage medium

A data collection method for controlling a data collection system which comprising a data server and a plurality of data collection devices which are communicably connected via a first network to the data server, the data collection method comprising:

• collecting data from a data input device that generates data indicating a physical quantity;
• adding a time stamp to the collected data;
• storing the data to which the time stamp is added;
• generating a timing at which the stored data is transmitted to the data server;
• acquiring request information for requesting transmission of the data, the request information being transmitted from the data server;
• and
• transmitting the stored data to the data server based on the generated timing and according to the acquired request information,
• wherein time servers, which are different from each other and each of which provides time information, are respectively provided for the data collection devices,
• wherein the data collection devices are directly connected to the time servers respectively without passing through any network,
• wherein the data collection method further comprises:
• adding the time stamp to the data based on the time information provided by one of the time servers before the data is transmitted via the first network to the data server;
• in response to determining that the request information from the data server has been acquired, monitoring a communication status indicating whether or not a communication with the data server is possible, and in response to the communication status indicating that the communication is possible, transmitting the stored data to the data server,
• in response to determining that the request information from the data server has not been acquired, monitoring the communication status, and in response to the communication status indicating that the communication is possible, transmitting the stored data to the data server,
• in response to determining that a change which is larger than a predetermined value does not occur in the data, transmitting the data at a low transmission frequency, and in response to determining that the change which is larger than the predetermined value occurs in the data, transmitting the data at a high transmission frequency, and
• in response to the communication status indicating that the communication is not possible, waiting for the communication status to indicate that the communication is possible.

A non-transitory computer readable storage medium storing one or more data collection programs configured for execution by a computer of a data collection system which comprising a data server and a plurality of data collection devices which are communicably connected via a first network to the data server, the one or more data collection programs comprising instructions for:

• collecting data from a data input device that generates data indicating a physical quantity;
• adding a time stamp to the collected data;
• storing the data to which the time stamp is added;
• generating a timing at which the stored data is transmitted to the data server;
• acquiring request information for requesting transmission of the data, the request information being transmitted from the data server;
• and
• transmitting the stored data to the data server based on the generated timing and according to the acquired request information,
• wherein time serves, which are different from each other and each of which provides time information, are respectively provided for the data collection devices,
• wherein the data collection devices are directly connected to the time servers respectively without passing through any network,
• wherein the one or more data collection programs further comprises instructions for:
• adding the time stamp to the data based on the time information provided by one of the time servers before the data is transmitted via the first network to the data server;
• when the request information from the data server has been acquired, monitoring a communication status indicating whether or not a communication with the data server is possible, and when the communication status indicates that the communication is possible, transmitting the stored data to the data server,
• when the request information from the data server has not been acquired, monitoring the communication status, and when the communication status indicates that the communication is possible, transmitting the stored data to the data server,
• when a change which is larger than a predetermined value does not occur in the data, transmitting the data at a low transmission frequency, and when the change which is larger than the predetermined value occurs in the data, transmitting the data at a high transmission frequency, and
• when the communication status indicates that the communication is not possible, waiting for the communication status to indicate that the communication is possible.