# US 9,438,363 B2 · Communication device, communication system, and synchronous control method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,438,363 B2 - Document ID: US9438363B2 - Status: Granted - Kind: B2 - Application number: 14/406,574 - Filed: 2012-08-01 - Published: 2015-06-25 - Granted: 2016-09-06 - Earliest claimed: 2012-08-01 - Assignees: Mitsubishi Electric Corporation - Applicants: Satoshi Arakawa - Inventors: Satoshi Arakawa - Web page: https://patentgrep.com/patent/US9438363B2 ## CPC - H04J 3/0602: {Systems characterised by the synchronising information used} - G05B 15/02: electric - H04J 3/0658: {Clock or time synchronisation among packet nodes} - H04L 7/0008: {Synchronisation information channels, e.g. clock distribution lines} - H04L 7/04: Speed or phase control by synchronisation signals {(H04L7/0075 takes precedence)} - H04L 12/40: Bus networks - H04J 3/0682: {by delay compensation, e.g. by compensation of propagation delay or variations thereof, by ranging} - H04L 2012/4026: {Bus for use in automation systems} - H04J: MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L5/00; systems for the simultaneous or sequential transmission of more than one television signal H04N7/08; in exchanges H04Q11/00; stereophonic systems H04S) - G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A communication device includes a transmission port and a reception port communicating with other network units, a system bus I/F unit communicating with a synchronous target, n (n is an integer of 2 or more) delay counters counting a predetermined period of time, a delay-counter control unit that, upon receiving a synchronous packet input with a predetermined cycle from the reception port, causes the delay counters to count a cycle that is n times as long as the predetermined cycle and controls the delay counters such that counts of the delay counters are cleared at different timings, and a synchronous-pulse output unit outputting a synchronous pulse to the synchronous target through the system bus I/F unit when there is the counter whose count value after being cleared becomes equal to a synchronous-pulse output value. ## Claims ### Claim 1 A communication device comprising: a first communication unit that communicates with another communication device; a second communication unit that communicates with a synchronous target; n (n is an integer of 2 or more) counters that count a predetermined period of time; a counter control unit that, upon receiving a synchronous packet input with a predetermined cycle from the first communication unit, causes the counters to count a cycle that is n times as long as the predetermined cycle and controls the counters such that counts of the counters are cleared at different timings; and a synchronous-pulse output unit that outputs a synchronous pulse to the synchronous target through the second communication unit when there is a counter whose count value after being cleared becomes equal to a synchronous-pulse output value. ### Claim 2 (depends on 1) The communication device according to claim 1, further comprising a filter unit that restricts a timing of clearing a count of the counter within a predetermined time range with reference to a time when the cycle that is n times as long as the predetermined cycle has elapsed since the counter starts counting, wherein the filter unit is provided to each of the counters. ### Claim 3 (depends on 1) The control device according to claim 1, further comprising: a synchronous-packet transmission unit that causes clear-counter designation information to be included in the synchronous packet, where the clear-counter designation information designates a counter whose count is to be cleared among the n counters; and a synchronous-packet reception unit that, upon receiving the synchronous packet, notifies the counter control unit of a counter designated by the clear-counter designation information in the synchronous packet having been received, wherein the counter control unit clears a count of the counter, the counter control unit being notified of the counter from the synchronous-packet reception unit. ### Claim 4 A communication system in which a first communication device connected to a synchronous master that outputs a synchronous pulse regularly and a plurality of second communication devices connected to a synchronous target are connected through a network, wherein the synchronous master includes a synchronous-signal transmission unit that outputs a synchronous pulse with a predetermined cycle, and a communication-delay-time measurement unit that measures a communication delay time from the synchronous master to the second communication devices connected to the synchronous target and that sets a synchronous-pulse output value calculated on a basis of the communication delay time for each of the second communication devices, the first communication device includes a synchronous-packet transmission unit that transmits a synchronous packet to all the second communication devices connected to the network upon receiving the synchronous pulse from the synchronous master, and the second communication device includes a first communication unit that communicates with the first communication device or another second communication device, a second communication unit that communicates with the synchronous target, n (n is an integer of 2 or more) counters that count a predetermined period of time, a counter control unit that, upon receiving the synchronous packet from the first communication unit with a predetermined cycle, causes the counters to count a cycle that is n times as long as the predetermined cycle and controls the counters such that counts of the counters are cleared at different timings, and a synchronous-pulse output unit that outputs a synchronous pulse to the synchronous target through the second communication unit when there is a counter whose count value after being cleared becomes equal to the synchronous-pulse output value. ### Claim 5 (depends on 4) The communication system according to claim 4, wherein the second communication device further includes, for each of the counters, a filter unit that restricts a timing of clearing a count of the counter within a predetermined time range with reference to a time when the cycle that is n times as long as the predetermined cycle has elapsed since the counter starts counting. ### Claim 6 (depends on 4) The communication system according to claim 4, wherein the second communication device further includes a synchronous-packet transmission unit that causes clear-counter designation information to be included in the synchronous packet, where the clear-counter designation information designates a counter whose count is to be cleared among the n counters in the second communication device, and a synchronous-packet reception unit that, upon receiving the synchronous packet, notifies the counter control unit of a counter designated by the clear-counter designation information in the synchronous packet having been received, and the counter control unit clears a count of the counter, the counter control unit being notified of the counter from the synchronous-packet reception unit. ### Claim 7 (depends on 4) The communication system according to claim 4, wherein the synchronous master and the first communication device are connected through a system bus, and the synchronous target and the second communication devices are connected through a system bus. ### Claim 8 (depends on 4) The communication system according to claim 4, wherein a cycle of the synchronous pulse is shorter than a delay time in the second communication device that is located such that a length from the first communication device connected through the network is longest relative to the second communication device that is located such that a length from the first communication device connected through the network is shortest. ### Claim 9 A synchronous control method in a communication system in which a first communication device connected to a synchronous master that outputs a synchronous pulse regularly and a plurality of second communication devices connected to a synchronous target are connected through a network, the method comprising: a first step of, by the first communication device, transmitting a synchronous packet to all the second communication devices connected through the network upon receiving the synchronous pulse from the synchronous master; a second step of, by the second communication device, clearing, among n (n is an integer of 2 or more) counters, a counter that has counted the number equal to a synchronous-pulse output value and starting counting anew upon receiving the synchronous packet; and a third step of, by the second communication device, outputting a synchronous pulse to the synchronous target connected to the second communication device when, among the n counters, there is the counter that has counted a value equal to a synchronous-pulse output value that is set according to a length from the synchronous master connected through the network.