Time synchronization system, master device, slave device, and program

A master device connected to a slave device via a data communication line and a signal line dedicated to transmission of a fixed-period signal, the master device comprising:

• a master timekeeper to measure a time;
• a fixed-period signal transmitter to, regularly at a transmission period, generate the fixed-period signal and transmit the fixed-period signal to the slave device through the signal line;
• a start time transmitter to transmit, to the slave device through the data communication line, start time information indicating a transmission start time at which transmission of the fixed-period signal is started;
• and
• a transmission period transmitter to transmit, to the slave device through the data communication line, the transmission period information indicating the transmission period for the fixed-period signal.

A slave device connected to a master device via a data communication line and a signal line dedicated to transmission of a fixed-period signal, the slave device comprising:

• a slave timekeeper to measure a time;
• a fixed-period signal receiver to receive the fixed-period signal transmitted regularly at a transmission period from the master device through the signal line;
• a start time receiver to receive, from the master device through the data communication line, start time information indicating a transmission start time at which transmission of the fixed-period signal is started;
• a transmission period receiver to receive, from the master device through the data communication line, transmission period information indicating the transmission period for the fixed-period signal;
• a counter to count a number of times the fixed-period signal is received by the fixed-period signal receiver;
• a time calculator to calculate, as a current time in the master device, a transmission time at which the master device transmits the fixed-period signal, based on the transmission start time indicated by the start time information, the transmission period indicated by the transmission period information, and the number of times the fixed-period signal is received;
• and
• a time corrector to correct the time measured by the slave timekeeper to the current time in the master device calculated by the time calculator.

A non-transitory computer readable recording medium storing a program for causing a computer connected to a slave device via a data communication line and a signal line dedicated to transmission of a fixed-period signal to function as:

• a master timekeeper to measure a time;
• a fixed-period signal transmitter to generate, regularly at a transmission period, the fixed-period signal and transmit the fixed-period signal to the slave device through the signal line;
• a start time transmitter to transmit, to the slave device through the data communication line, start time information indicating a transmission start time at which transmission of the fixed-period signal is started;
• and
• a transmission period transmitter to transmit, to the slave device through the data communication line, transmission period information indicating the transmission period for the fixed-period signal.

A non-transitory computer readable recording medium storing a program for causing a computer connected to a master device via a data communication line and a signal line dedicated to transmission of a fixed-period signal to function as:

• a slave timekeeper to measure a time;
• a fixed-period signal receiver to receive the fixed-period signal transmitted regularly at a transmission period from the master device through the signal line;
• a start time receiver to receive, from the master device through the data communication line, start time information indicating a transmission start time at which transmission of the fixed-period signal is started;
• a transmission period receiver to receive, from the master device through the data communication line, transmission period information indicating the transmission period for the fixed-period signal;
• a counter to count a number of times the fixed-period signal is received by the fixed-period signal receiver;
• a time calculator to calculate, as a current time in the master device, a transmission time at which the master device transmits the fixed-period signal, based on the transmission start time indicated by the start time information, the transmission period indicated by the transmission period information, and the number of times the fixed-period signal is received;
• and
• a time corrector to correct the time measured by the slave timekeeper to the current time in the master device calculated by the time calculator.