A communication system comprising a data collection apparatus, a first industrial machine and a second industrial machine, wherein the first industrial machine and the second industrial machine are configured to communicate to/from each other, the data collection apparatus is configured to transmit a logging start request that is a request for starting an acquisition of state data to be stored in a logging file, the first industrial machine includes a synchronization module configured to use synchronous communication to synchronize first time information updated by the first industrial machine and second time information updated by the second industrial machine with each other, after the first industrial machine receives the logging start request from the data collection apparatus, the first industrial machine includes an acquisition start request module configured to use asynchronous communication to request the second industrial machine to start the acquisition of the state data on the second industrial machine; and the second industrial machine includes: an acquisition module configured to acquire the state data when the acquisition start request is received from the first industrial machine through use of the asynchronous communication; and a transmission module configured to transmit to the first industrial machine the second time information indicating a time when the state data is acquired and the state data, the second industrial machine further includes a determination module configured to determine whether a predetermined trigger condition is satisfied, wherein the acquisition module is configured to acquire the state data when the predetermined trigger condition is satisfied, the first industrial machine is configured to create and store the logging file that includes the second time information and the state data, after the first industrial machine receives the second time information and the state data from the second industrial machine, the first industrial machine is configured to transmit the logging file to the data collection apparatus, and the data collection apparatus is configured to receive the logging file from the first industrial machine. a data collection apparatus, a first industrial machine and a second industrial machine, wherein the first industrial machine and the second industrial machine are configured to communicate to/from each other, the data collection apparatus is configured to transmit a logging start request that is a request for starting an acquisition of state data to be stored in a logging file, the first industrial machine includes a synchronization module configured to use synchronous communication to synchronize first time information updated by the first industrial machine and second time information updated by the second industrial machine with each other, after the first industrial machine receives the logging start request from the data collection apparatus, the first industrial machine includes an acquisition start request module configured to use asynchronous communication to request the second industrial machine to start the acquisition of the state data on the second industrial machine; and the second industrial machine includes: an acquisition module configured to acquire the state data when the acquisition start request is received from the first industrial machine through use of the asynchronous communication; and a transmission module configured to transmit to the first industrial machine the second time information indicating a time when the state data is acquired and the state data, an acquisition module configured to acquire the state data when the acquisition start request is received from the first industrial machine through use of the asynchronous communication; and a transmission module configured to transmit to the first industrial machine the second time information indicating a time when the state data is acquired and the state data, the second industrial machine further includes a determination module configured to determine whether a predetermined trigger condition is satisfied, wherein the acquisition module is configured to acquire the state data when the predetermined trigger condition is satisfied, the first industrial machine is configured to create and store the logging file that includes the second time information and the state data, after the first industrial machine receives the second time information and the state data from the second industrial machine, the first industrial machine is configured to transmit the logging file to the data collection apparatus, and the data collection apparatus is configured to receive the logging file from the first industrial machine.