Method for the automatic time synchronisation of devices in network-based systems

• US 8,838,776 B2
• Filed: 08/19/2008
• Issued: 09/16/2014
• Est. Priority Date: 09/26/2007
• Status: Active Grant

• Current Assignee: VEGA Grieshaber KG (Grieshaber Verwaltungsgesellschaft mbH)
• Original Assignee: VEGA Grieshaber KG (Grieshaber Verwaltungsgesellschaft mbH)
• Inventors: Faist, Fridolin
• Primary Examiner(s): Baturay, Alicia
• Application Number:
  US12/194,057
• Publication Number:
  US 20090083444A1
• Time in Patent Office: 2,219 Days
• Field of Search: 709/224
• US Class Current: 709/224
• CPC Class Codes: G05B 19/042 using digital processors G05B19/05 takes precedence
• CPC Class Codes: G05B 2219/25478 Synchronize several controllers using syncline
• CPC Class Codes: G05B 2219/25479 Synchronize controllers using messages, add transmission time afterwards
• CPC Class Codes: G06F 1/14 Time supervision arrangements, e.g. real time clock
• CPC Class Codes: 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

Abstract

A method is based on a communication- and data network for the automatic time synchronization of field devices, namely fill-level measuring devices and pressure measuring devices as well as field-device control units. The method comprises the steps of: determining a current time value by the field device or by the field-device control unit, and providing a desired value in a central server. Furthermore, the method comprises the following steps: comparing the current time value with the desired value, and setting the current time value to the desired value when the desired value differs from the current time value by more than a predetermined threshold value.

Claims

1. A method based on a communication and data network for automatic time synchronization of fill-level measuring devices, pressure measuring devices, and field control units by a central server, comprising:

determining a current time value by at least one of the fill-level measuring devices, the pressure measuring devices, and the field control units;

transmitting the current time value to the server;

providing a desired value in the central server;

comparing the current time value with the desired value by the central server, the comparing being performed at the server;

wherein the server ensures that a correct conversion of the current time of day of the at least one of the fill-level measuring devices, the pressure measuring devices and the field control units is carried out,

when the desired value differs from the current time value by more than a predetermined threshold value, requesting, by the server, the at least one fill-level measuring device, pressure measuring device, and field control unit to carry out the time synchronization, after which that at least one fill-level measuring device, pressure measuring device, and field control unit sets the current time value to the desired value.

wherein the server takes over data from at least one of the fill-level measuring devices, the pressure measuring devices, or the field control units into a database only when the desired value differs from the current time value at most by the predetermined threshold value.

2. The method according to claim 1, wherein the fill-level measuring devices including at least two of pressure measuring devices and fill-level measuring device control units.

3. The method according to claim 1, further comprising:

transmitting the current time value by the fill-level measuring device to the server; and

determining a time difference between the current time value and the desired value.

4. The method according to claim 1, further comprising:

sending a reply by the server to the fill-level measuring device, the reply being indicative that the system time of the fill-level measuring device is acceptable if the desired value differs from the current time value at most by the predetermined threshold value;

transmitting all the data to be stored from the fill-level measuring device to the server; and

acknowledging receipt of the data by the server.

5. The method according to claim 1, further comprising:

transmitting a server time to the fill-level measuring device;

issuing a request for time synchronization of the fill-level measuring device with the server; and

storing the process of “

Time synchronization in the field device”

in a message buffer on the server.

6. The method according to claim 1, wherein the method is implemented in an acquisition system WEB-VV.

7. The method according to claim 1, further comprising:

requesting, by the server, the fill-level measuring device to carry out a comparison of clocks.

8. The method according to claim 1, further comprising:

only if the time in the server and the time in the fill-level measuring device are identical, permitting the server to take over the data.

9. The method according to claim 1, wherein at least one of the data groups of “

Time comparison data” and

“

Data to be stored”

is used in an XML-file format.

10. The method according to claim 1, wherein the fill-level measuring devices obtain the time information centrally using the server.

11. The method according to claim 1, wherein http communication is used between the server and the fill-level measuring devices.

12. The method according to claim 1, wherein the communication- and data network includes the Internet.

13. The method according to claim 1, wherein setting the current time value comprises time synchronization of the fill-level measuring device with correction of a real-time clock of the fill-level measuring device, and with correction of time stamps relating to data that is produced at that time in the fill-level measuring device.

14. The method according to claim 1, further comprising:

collecting various data records with associated time stamps in the fill-level measuring device; and

changing all the time stamps in the case of time synchronization.

15. The method according to claim 1, wherein the fill-level measuring device establishes contact with the server at predefined times using the communication- and data network.

16. A data and communication-network-based measuring system for measuring one of a fill level and a pressure and for the automatic time synchronization, comprising:

a server;

at least one of a fill-level measuring device, a pressure measuring device, and a field control unit determining a current time value;

a communication connection between the server and the at least one fill-level measuring device, pressure measuring device, and field control unit for mutual data transmission;

wherein the server provides a desired value in the server, compares the current time value with the desired time value at the server, and sets the current time value to the desired value when the desired value differs from the current time value by more than a predetermined threshold value,

wherein the server ensures that a correct conversion of the current time of day of the at least one of the fill-level measuring devices, the pressure measuring devices and the field control units is carried out,

wherein the server takes over data from at least one of the fill-level measuring devices, the pressure measuring devices, or the field control units into a database only when the desired value differs from the current time value at most by the predetermined threshold value.

17. The measuring system according to claim 16, wherein the at least one fill-level measuring device includes a fill-level measuring device control unit.

18. The measuring system according to claim 16, wherein the at least one fill-level measuring device generates and transmits time comparison data to the server, the server providing a threshold value relating to an allowed time difference and determining a time difference between the current time value and the desired value;

the server comparing the time difference with the threshold value and determining if the time difference is one of greater than and smaller than the threshold value, the server sending a reply to the at least one fill-level measuring device, the at least one fill-level measuring device transmitting a reply to the server, the reply being indicative if the time of the at least one fill-level measuring device is acceptable, the at least one fill-level measuring device carrying out time synchronization with a correction of time stamps of data produced at that moment being carried out in the at least one fill-level measuring device, the at least one fill-level measuring device transmitting to the server the data which is to be stored completely, the server taking over the data into a database, the server acknowledging data receipt via the communication and data network to the at least one fill-level measuring device, the server sending a server time to the at least one fill-level measuring device and requesting time synchronization of the at least one fill-level measuring device with the server and the server comprising a message buffer in which the server stores the process of “

Time synchronization in the field device”

.

19. A computer readable storage device including a set of instructions executable by a processor for automatic time synchronization of fill-level measuring devices, pressure measuring devices, and field control units by a central server in a communication and data network is stored, the set of instructions operable to:

determine a current time value by at least one of the fill-level measuring devices, the pressure measuring devices, and the field control units;

provide a desired value in the central server;

compare the current time value with the desired value by the central server, the comparison being performed at the server;

request, by the server, the at least one fill-level measuring device, pressure measuring device, and field control unit to carry out the time synchronization;

set, by the fill-level measuring devices, the pressure measuring devices, and the field control units, the current time value to the desired value when the desired value differs from the current time value by more than a predetermined threshold value,

wherein the server ensures that a correct conversion of the current time of day of the at least one of the fill-level measuring devices, the pressure measuring devices and the field control units is carried out,

wherein the server takes over data from at least one of the fill-level measuring devices, the pressure measuring devices, or the field control units into a database only when the desired value differs from the current time value at most by the predetermined threshold value.

20. The computer readable storage device according to claim 19, wherein the fill-level measuring devices includes one of at least one pressure measuring device and at least one fill-level measuring device control unit.

21. A microprocessor device for the automatic time synchronization of fill-level measuring devices, pressure measuring devices, and field control units by a central server in a communication and data network, and for carrying out the following steps:

determining a current time value by at least one of the fill-level measuring devices, the pressure measuring devices, and the field control units;

providing a desired value in the central server;

comparing the current time value with the desired value by the central server, the comparing being performed at the server;

requesting, by the server, the at least one fill-level measuring device, pressure measuring device, and field control unit to carry out the time synchronization;

setting, by the fill-level measuring devices, the pressure measuring devices, and the field control units, the current time value to the desired value when the desired value differs from the current time value by more than a predetermined threshold value,

wherein the server ensures that a correct conversion of the current time of day of the at least one of the fill-level measuring devices, the pressure measuring devices and the field control units is carried out,

wherein the server takes over data from at least one of the fill-level measuring devices, the pressure measuring devices, or the field control units into a database only when the desired value differs from the current time value at most by the predetermined threshold value.

22. The microprocessor device according to claim 21, wherein the fill-level measuring devices includes one of at least one pressure measuring device and at least one fill-level measuring device control unit.