# US 12,009,914 B2 · Control system, communication control method of control system, and control device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,009,914 B2 - Document ID: US12009914B2 - Status: Granted - Kind: B2 - Application number: 17/771,710 - Filed: 2020-03-03 - Published: 2022-11-24 - Granted: 2024-06-11 - Earliest claimed: 2019-11-01 - Assignees: OMRON Corporation - Applicants: Omron Corporation - Inventors: Takamasa Ueda - Web page: https://patentgrep.com/patent/US12009914B2 ## CPC - H04J 3/0638: {Clock or time synchronisation among nodes; Internode synchronisation (synchronization for ring networks H04L12/422; data switching networks with synchronous transmission H04L12/43)} - H04J 3/14: Monitoring arrangements {(for SDH/SONET rings H04J3/085)} - G05B 19/05: Programmable logic controllers, e.g. simulating logic interconnections of signals according to ladder diagrams or function charts - H04J 3/0667: {Bidirectional timestamps, e.g. NTP or PTP for compensation of clock drift and for compensation of propagation delays (arrangements for monitoring round trip delays in packet switching networks H04L43/0864)} - H04L 67/1095: Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes - H04L 67/55: Push-based network services - H04L 69/28: Timers or timing mechanisms used in protocols - G05B 2219/13063: Synchronization between modules - Y02P 90/02: Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS] - 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) - Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS ## Abstract The communication master repeats transmission of first information indicating a counter value of a synchronization counter of the communication master to the one or more communication slaves through a network. Each of the one or more communication slaves updates the counter value of the synchronization counter of each of the one or more communication slaves based on the received first information upon receiving the first information from the communication master. The communication master manages a total number of pieces of the first information transmitted for each of the one or more communication slaves, and estimates synchronization accuracy with respect to the communication master for each communication slave based on a number of transmissions of the first information for each communication slave. ## Claims ### Claim 1 A control system comprising: a communication master; and one or more communication slaves connected to the communication master by a network, wherein each of the communication master and the one or more communication slaves comprises a synchronization counter, the communication master is configured to repeat transmission of a control frame including a counter value of the synchronization counter of the communication master to the one or more communication slaves through the network, each of the one or more communication slaves is configured to receive the control frame and update the counter value of the synchronization counter of the communication slave based on the received control frame, and the communication master is configured to manage a total number of the control frames transmitted for each of the one or more communication slaves, and estimate a synchronization accuracy with respect to the communication master for each communication slave based on a number of transmissions of the control frames for each communication slave. ### Claim 2 (depends on 1) The control system according to claim 1, wherein: the communication master is a control device configured to execute a user program, and the user program refers to the synchronization accuracy estimated for each communication slave. ### Claim 3 (depends on 2) The control system according to claim 2, wherein the synchronization accuracy estimated for each communication slave is indicated in a structure variable. ### Claim 4 (depends on 2) The control system according to claim 2, wherein the one or more communication slaves comprises a plurality of communication slaves, and wherein in the user program, the synchronization accuracy for each of a plurality of predetermined communication slaves of the plurality of communication slaves are combined together as a combined synchronization accuracy. ### Claim 5 (depends on 4) The control system according to claim 4, wherein the combined synchronization accuracy is output from a function block command. ### Claim 6 (depends on 1) The control system according to claim 1, wherein the communication master is configured to determine the synchronization accuracy of one of the one or more communication slaves based on the number of transmissions of the control frame for the one of the one or more communication slaves with respect to a threshold number of transmissions. ### Claim 7 (depends on 1) The control system according to claim 1, wherein when an additional communication slave is newly connected to the network, the communication master is configured to reset the number of transmissions of the control frames for the additional communication slave. ### Claim 8 (depends on 1) The control system according to claim 1, wherein each of the one or more communication slaves is configured to update the counter value of the synchronization counter of the communication slave based on the control frame received from the communication master and a propagation delay time acquired in advance. ### Claim 9 A communication control method of a control system comprising a communication master and one or more communication slaves connected to the communication master by a network, each of the communication master and the one or more communication slaves comprising a synchronization counter, the communication control method comprising: repeating, by the communication master, transmission of a control frame including a counter value of the synchronization counter of the communication master to the one or more communication slaves through the network; receiving, by each of the one or more communication slaves, the control frame and updating, by each of the one or more communication slaves, the counter value of the synchronization counter of the communication slaves based on the received control frame; managing, by the communication master, a total number of the control frames transmitted for each of the one or more communication slaves; and estimating, by the communication master, a synchronization accuracy with respect to the communication master for each communication slave based on a number of transmissions of the control frame for the communication slave. ### Claim 10 (depends on 9) The communication control method according to claim 9, wherein: the communication master is a control device configured to execute a user program, and the user program refers to the synchronization accuracy estimated for each communication slave. ### Claim 11 (depends on 10) The communication control method according to claim 10, wherein the synchronization accuracy estimated for each communication slave is indicated in a structure variable. ### Claim 12 (depends on 10) The communication control method according to claim 10, wherein the one or more communication slaves comprises a plurality of communication slaves, and wherein in the user program, the synchronization accuracy for each of a plurality of predetermined communication slaves of the plurality of communication slaves are combined together as a combined synchronization accuracy. ### Claim 13 (depends on 12) The communication control method according to claim 12, wherein the combined synchronization accuracy is output from a function block command. ### Claim 14 (depends on 9) The communication control method according to claim 9, wherein the estimating comprises determining the synchronization accuracy of one of the one or more communication slaves based on the number of transmissions of the control frame for the one of the one or more communication slaves with respect to a threshold number of transmissions. ### Claim 15 A control device that functions as a communication master connected to one or more communication slaves by a network, the control device comprising: a synchronization counter, wherein the communication master is configured to: repeat transmission of a control frame including a counter value of the synchronization counter of the control device to the one or more communication slaves through the network, each of the one or more communication slaves receiving the control frame and updating the counter value of the synchronization counter of the communication slave based on the received control frame, and manage a total number of the control frames transmitted for each of the one or more communication slaves and estimate a synchronization accuracy with respect to the communication master for each communication slave based on the number of transmissions of the control frame for the communication slave. ### Claim 16 (depends on 15) The control device according to claim 15, wherein: the control device is configured to execute a user program, and the user program refers to the synchronization accuracy estimated for each communication slave. ### Claim 17 (depends on 16) The control device according to claim 16, wherein the synchronization accuracy estimated for each communication slave is indicated in a structure variable. ### Claim 18 (depends on 16) The control device according to claim 16, wherein the one or more communication slaves comprises a plurality of communication slaves, and wherein in the user program, the synchronization accuracy for each of a plurality of predetermined communication slaves of the plurality of communication slaves are combined together as a combined synchronization accuracy. ### Claim 19 (depends on 18) The control device according to claim 18, wherein the combined synchronization accuracy is output from a function block command. ### Claim 20 (depends on 15) The control device according to claim 15, wherein the control device is configured to determine the synchronization accuracy of one of the one or more communication slaves based on the number of transmissions of the control frame for the one of the one or more communication slaves with respect to a threshold number of transmissions.