TIMESTONE SYNC THROUGH SERIAL CONNECTION

Description

[0001] The invention relates to the field of electricity meters, and in particular industrial meters. BACKGROUND OF THE INVENTION

[0002] Some modern industrial electricity meters are designed to measure, in addition to the electrical energy consumption of the installation to which they are connected, parameters of the quality of the power supplied by the electrical energy distribution network.

[0003] Power quality parameters include, among other things, the frequency and amplitude of the supply voltage, dips, surges, voltage cuts, voltage imbalance, etc.

[0004] The International Electrotechnical Commission (IEC) has produced the IEC 61000-4-30 quality measurement standard which defines how to measure these parameters.

[0005] To comply with the IEC 61000-4-30 class A standard, electricity meters must have a very precise clock that allows them to time-stamp the occurrence of different events on the network very precisely.

[0006] The very precise timestamping of events makes it possible, in particular by analyzing the data from several counters, to know where in the network the event occurred.

[0007] This clock must not deviate by more than one network period from UTC time (for Coordinated Universal Time, which is translated as Coordinated Universal Time), which corresponds, for a supply voltage frequency of 60 Hz, to + / - 16.67 ms.

[0008] However, the internal clocks of the meters have a natural drift, mainly due to the oscillators. It is therefore necessary to regularly resynchronize the meters to UTC time.

[0009] In order to achieve time synchronization, some current meters are equipped with a signal hardware (On / Off input) often called a "TOP SYNCHRO signal," allowing a reference clock (with access to UTC time) to synchronize the meter's internal clock. This solution therefore requires a dedicated port, which increases the cost of the meter.

[0010] US patent 11,662,475 B2 describes a method for timestamping one or more asynchronous sensor measurements in a global satellite navigation system. Sensor measurement data is received at a first port. A signal pulse, representing a measurement time, is received at a second port.

[0011] Other meters include an NTP server (for Network Time Protocol, which is translated as network time protocol) allowing this synchronization, either through a radio link (GPS), or via a wired link with the IEEE 1588 protocol (Ethernet link).

[0012] These solutions are increasingly being rejected by energy distributors and even subscribers because they are easily hacked. Furthermore, these solutions are relatively expensive. SUBJECT OF THE INVENTION

[0013] The invention aims to resynchronize the internal clock of an electric meter in a simple, inexpensive and secure manner. SUMMARY OF THE INVENTION

[0014] To achieve this goal, a method for synchronizing the internal clock of an electricity meter is proposed, comprising a first processing unit including a first port arranged to be connected to external equipment. The synchronization method includes the first steps, implemented successively by the first processing unit and repeated at predefined intervals, of: • Receive via the first port a first frame transmitted by the external equipment using a serial link, and containing a reference time; • Configure the first port to operate in an interrupt trigger mode; • Receive via the first port a pulse, transmitted by the external equipment and defining a synchronization time, and trigger an interrupt leading to the recording of the reference time as the current time at the synchronization time; • Reconfigure the first port to communicate via the first port using the serial link.

[0015] The synchronization of the electricity meter's internal clock is therefore performed by equipment external to the meter, such as a modem, via a serial connection. A pre-existing serial connection can thus be used, so implementing the synchronization process does not require an additional connection and is simple and inexpensive. This serial connection is also difficult to hack.

[0016] We also propose a synchronization process as previously described, in which the first steps further include the step, following the reception of the first frame, of transmitting via the first port, to the external equipment and using the serial link, a second frame containing an acknowledgment message.

[0017] We also propose a synchronization method as previously described, in which the time between the transmission of the first frame and the transmission of the second frame is a predefined time between 1 s and 3 s.

[0018] We also propose a synchronization process as previously described, in which the first steps further include the step, following the reconfiguration of the first port, of transmitting via the first port, to the external equipment and using the serial link, a third frame containing information indicating the end of the time setting.

[0019] We also propose a synchronization method as previously described, in which the interrupt is a rising edge interrupt.

[0020] We also propose a synchronization method as previously described, in which the serial link is an RS-232 link.

[0021] We also propose an electric meter comprising a first processing unit including a first port, in which the first steps of the synchronization process as previously described are implemented.

[0022] We also propose an electric meter as previously described, the electric meter being further arranged to monitor an electric power distribution network to which it is connected, to time-stamp events occurring on the electric power distribution network using the current time, and to transmit network monitoring information to external equipment using the serial link.

[0023] We also propose a computer program comprising instructions which lead the first processing unit of the electric meter as previously described to execute the first steps of the synchronization process as previously described.

[0024] In addition, a computer-readable recording medium is proposed, on which the computer program as previously described is recorded.

[0025] We further propose a method for synchronizing the internal clock of an electricity meter arranged to be connected to external equipment comprising a second processing unit having a second port arranged to be connected to the electricity meter, the synchronization method comprising the second steps, implemented successively by the second processing unit and repeated at predefined intervals, of: • transmit via the second port, to the electricity meter and using a serial link, a first frame containing a reference time; • configure the second port to operate in a pulse generation mode; • transmit via the second port, to the electricity meter, a pulse defining a synchronization time; • reconfigure the second port to communicate via the second port using the serial link.

[0026] We also propose a synchronization method as previously described, in which the pulse has a defined duration with an accuracy of + / - 1 ms.

[0027] We also propose a synchronization method as previously described, in which the second steps further include the step, following the transmission of the first frame, of waiting, before configuring the second port to operate in pulse generation mode, to receive via the second port a second frame containing an acknowledgment message.

[0028] We also propose a modem comprising a second processing unit with a second port, in which the second stages of the synchronization process as previously described are implemented.

[0029] We also propose a computer program comprising instructions which lead the second processing unit of the modem as previously described to execute the second stages of the synchronization process as previously described.

[0030] In addition, a computer-readable recording medium is proposed, on which the computer program as previously described is recorded.

[0031] We also propose a system comprising an electricity meter as previously described, and a modem as previously described.

[0032] The invention will be better understood in light of the following description of a particular, non-limiting embodiment of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Reference will be made to the attached drawings, among which: [ Fig. 1 ] there figure 1 represents a system comprising an electricity meter and a modem; [ Fig. 2 ] there figure 2 illustrates a clock synchronization phase of the meter; [ Fig. 3 ] there figure 3 represents the steps of a synchronization phase. DETAILED DESCRIPTION OF THE INVENTION

[0034] With reference to the figure 1 , system 0 includes a meter 1 and equipment external to meter 1, in this case a modem 2.

[0035] Meter 1 is an industrial electric meter which is here connected to an electrical power distribution network 3 which is a three-phase network and which includes a first phase L1, a second phase L2, a third phase L3 and a neutral N.

[0036] Electric meter 1 is connected to an industrial electrical installation, to which network 3 supplies electrical energy.

[0037] Meter 1 is also connected to modem 2.

[0038] Counter 1 includes a first processing unit 5.

[0039] The first processing unit 5 is here designed, classically, to acquire and process current and voltage measurements taken by the sensors of the meter 1, in order to measure the electrical energy consumed by the installation.

[0040] The first processing unit 5 is also designed to measure power quality parameters supplied by network 3, and to time-stamp events occurring on network 3.

[0041] The first processing unit 5 comprises at least one first processing component 6.

[0042] The first processing component 6 is, for example, a "general-purpose" processor, a microcontroller, a processor specialized in signal processing (or DSP, for Digital Signal Processor), or a programmable logic circuit such as an FPGA (for Field Programmable Gate Arrays) or an ASIC (for Application Specific Integrated Circuit ) .

[0043] The first processing component 6 here is a microcontroller.

[0044] The first processing unit 5 further includes one or more memories 7, connected to or integrated into the first processing component 6. At least one of these memories 7 forms a computer-readable recording medium, on which is recorded at least one computer program comprising instructions which lead the first processing component 6 to execute the first steps of the synchronization phases which will be described.

[0045] The first processing unit 5 has at least one first port 8, which can be configured in a serial communication mode, in which the first port 8 can be used to implement a serial link (here RS-232), and in an interrupt triggering mode.

[0046] The first port 8 is a port of the first processing component 6 and includes two pins (pins) of the first processing component 6.

[0047] The first port 8 is a UART-configurable port (for Universal Asynchronous Receiver Transmitter) or in GPIO mode (for General Purpose Input / Output, which can be translated as General Purpose Input-Output).

[0048] Thus, here, the serial communication mode corresponds to the UART mode, and the interrupt triggering mode corresponds to the GPIO mode.

[0049] The first processing unit 5 also includes an internal clock 9, which is used in particular to timestamp the events mentioned earlier occurring on the distribution network 3.

[0050] Modem 2 is designed to form a communication interface between meter 1 (and possibly other meters) and a communication network 10 (the internet, for example). Meter 1 therefore communicates with network 10 via modem 2.

[0051] Modem 2 has access to UTC time through its connection to network 10.

[0052] Modem 2 includes a second processing unit 11 comprising at least a second processing component 12.

[0053] The second processing component 12 is, for example, a "general-purpose" processor, a microcontroller, a processor specialized in signal processing (or DSP, for Digital Signal Processor), or a programmable logic circuit such as an FPGA (for Field Programmable Gate Arrays) or an ASIC (for Application Specific Integrated Circuit ) .

[0054] The second processing component 12 is here a microcontroller.

[0055] The second processing unit 11 further includes one or more memories 14, connected to or integrated into the second processing component 12. At least one of these memories 14 forms a computer-readable recording medium, on which is recorded at least one computer program comprising instructions which lead the second processing component 12 to execute the second steps of the synchronization phases which will be described.

[0056] The second processing unit 11 has at least one second port 15, which can be configured in a serial communication mode, in which the second port 15 can be used to implement the serial link (here RS-232), and a pulse generation mode, allowing interrupts to be generated in the first processing unit 5 from outside the counter 1.

[0057] The second port 15 is a port of the second processing component 12 and includes two pins (pins) of the second processing component 12.

[0058] The second port 15 is a port that can be configured in UART mode or GPIO mode.

[0059] Thus, here, the serial communication mode corresponds to the UART mode, and the pulse generation mode corresponds to the GPIO mode.

[0060] The first port 8 of the meter 1 and the second port 15 of the modem 2 are connected by a cable 16 comprising two wires 17, 18 each connecting one leg of the first port 8 to one leg of the second port 15.

[0061] When the first port 8 and the second port 15 are configured in serial communication mode, the meter 1 and the modem 2 exchange data using the RS-232 serial link, via the first port 8, the second port 15 and wires 17, 18. The modem 2 transmits data to the meter 1 via wire 17, and the meter 1 transmits data to the modem 2 via wire 18.

[0062] Regularly, in reference to figures 2 And 3 , modem 2 triggers the synchronization of the internal clock 9 of counter 1 to UTC time.

[0063] The synchronization phase is repeated at predefined intervals (fixed or variable), for example every day or every week.

[0064] Each synchronization phase includes first steps E1, implemented successively by the first processing unit 5 of the electric meter 1, and second steps E2, implemented successively by the second processing unit 11 of the modem 2.

[0065] The first steps E1 and the second steps E2 are therefore repeated at predefined intervals.

[0066] Each synchronization phase begins when the first port 8 and the second port 15 are in serial communication mode.

[0067] Modem 2 acquires UTC time from network 10 and produces from UTC time a reference time corresponding to the current time at a synchronization time Tsync.

[0068] Then, at a predefined time preceding the Tsync time, for example at Tsync - 3 s, the second processing unit 11 of modem 2 transmits via the second port 15, to the counter 1 and using the serial link, a first frame 21 containing the reference time: step E2a.

[0069] The reference time is expressed, for example, in hours, minutes, seconds, and milliseconds, and for example in the format: hh.mm.ss.ms with h for hour, m for minute, s for second, ms for millisecond.

[0070] The first processing unit 5 of counter 1 then receives the first frame 21 via the first port 8.

[0071] Following the reception of the first frame 21, the counter 1 transmits via the first port 8, to modem 2 and using the serial link, a second frame 22 containing an acknowledgment message: step E1a.

[0072] The duration between the transmission of the first frame 21 and the transmission of the second frame 22 is equal to a predefined duration, which is for example between 1 s and 3 s.

[0073] Here, this predefined duration is less than a maximum duration of, for example, 2 seconds.

[0074] The second frame 22 is transmitted at a time preceding Tsync with a duration of, for example, 1 s.

[0075] This " timeout » of 2s (for example) is added so as not to block RS-232 communication.

[0076] As long as this acknowledgment frame 22 is not transmitted, modem 2 retransmits the first frame 21 containing the reference time.

[0077] After emitting the second frame 22, the first processing unit 5 of counter 1 configures the first port 8 to operate in interrupt mode: step E1b.

[0078] The second processing unit 11 of modem 2 configures the second port 15 to operate in pulse generation mode: step E2b.

[0079] The second processing unit 11 then sends via the second port 15, to the counter 1, a pulse 23: step E2c.

[0080] This pulse 23 begins with a falling edge and ends with a rising edge. The pulse is calibrated very precisely. It has a defined duration with an accuracy of + / - 1 ms. This duration is 10 ms.

[0081] Pulse 23 defines the synchronization time, which here corresponds to the rising edge. Pulse 23 is therefore emitted at time: Tsync - 10 ms.

[0082] The first processing unit 5 then receives this pulse 23 via the first port 8, and triggers an interrupt leading to the recording of the reference time as the current time at the synchronization time: step E1c.

[0083] The interruption here is a rising edge interrupt.

[0084] The first processing unit 5 reconfigures the first port 8 to communicate via the first port 8 using the serial link (serial communication mode). The modem 2 reconfigures the second port 15 to communicate via the second port 15 using the serial link (serial communication mode).

[0085] The first processing unit 5 then transmits via the first port 8, to modem 2 and using the serial link, a third frame 24 containing information for the end of time setting: step E1d.

[0086] Synchronization is complete.

[0087] The clock 9 of counter 1 is resynchronized. The current time is extremely precise. Its precision depends mainly on the precision of the time definition Tsync and therefore on the precision of the pulse duration 23 which, as we have seen, has been calibrated very precisely.

[0088] Meter 1 monitors the electrical power distribution network 3 to which it is connected, and, in particular, precisely timestamps events occurring on the distribution network 3 using the current time. From this monitoring, meter 1 generates network 3 monitoring information (including the time-stamped events) and transmits this network 3 monitoring information to modem 2 via cable 16 using the serial link.

[0089] Of course, the invention is not limited to the embodiment described but encompasses any variant falling within the scope of the invention as defined by the claims.

[0090] The serial link is not necessarily an RS-232 link; it could be another type of serial link, for example RS-485.

[0091] The synchronization time is defined by the interrupt (and therefore the impulse), but it could be a time other than that of a rising edge (and for example that of a falling edge, or a time defined by a predetermined duration following the interrupt).

[0092] The durations mentioned here (2 s, 10 ms, etc.) could be different.

[0093] The equipment connected to the meter is not necessarily a modem; it can be any equipment that can be connected to a meter via a serial link and has access to UTC time (for example, a data concentrator).

[0094] The transmission of the second frame is not mandatory: the modem could send the pulse that generates the interrupt without waiting for an acknowledgment. Similarly, the transmission of the third frame is not mandatory.

[0095] The invention can be implemented with a single-phase or polyphase meter (regardless of the number of phases).

Claims

1. Method for synchronising an internal clock (9) of an electricity meter (1) which comprises a first processing unit (5) comprising a first port (8) arranged to be connected to an external apparatus (2), the synchronisation method comprising the first steps (E1), carried out successively by the first processing unit (5) and repeated at predefined intervals: ∘ receiving, via the first port (8), a first frame (21) that is transmitted by the external apparatus using a serial link and contains a reference time; ∘ configuring the first port to operate in an interrupt-triggering mode; ∘ receiving, via the first port, a pulse (23) that is transmitted by the external apparatus and specifies a synchronisation time, and triggering an interrupt that leads to the reference time being recorded as a current time at the synchronisation time; ∘ reconfiguring the first port so as to communicate via the first port using the serial link.

2. Synchronisation method according to claim 1, wherein the first steps further comprise the step, following the receipt of the first frame (21), of transmitting a second frame (22), which contains an acknowledgement message, to the external apparatus via the first port (8) using the serial link.

3. Synchronisation method according to claim 2, wherein a length of time between the transmission of the first frame (21) and the transmission of the second frame (22) is a predefined length of time between 1 s and 3 s.

4. Synchronisation method according to any of the preceding claims, wherein the first steps further comprise the step, following the reconfiguration of the first port (8), of transmitting a third frame (24), which contains end of time-setting information, to the external apparatus (2) via the first port (8) using the serial link.

5. Synchronisation method according to any of the preceding claims, wherein the interrupt is a rising-edge interrupt.

6. Synchronisation method according to any of the preceding claims, wherein the serial link is an RS-232 link.

7. Electricity meter (1) comprising a first processing unit (8) which comprises a first port (8) and in which the first steps of the synchronisation method according to any of the preceding claims are carried out.

8. Electricity meter (1) according to claim 7, the electricity meter furthermore being arranged to monitor an electric power distribution network (3) to which it is connected, to timestamp events occurring on the electric power distribution network using the current time, and to send network monitoring information to the external apparatus (2) using the serial link.

9. Computer program comprising instructions that cause the first processing unit (5) of the electricity meter (1) according to any of claims 7 or 8 to execute the first steps of the synchronisation method according to any of claims 1 to 6.

10. Computer-readable storage medium on which the computer program according to claim 9 is stored.

11. Method for synchronising an internal clock (9) of an electricity meter (1) arranged to be connected to an external apparatus (2) which comprises a second processing unit (11) comprising a second port (15) arranged to be connected to the electricity meter, the synchronisation method comprising the following second steps (E2), carried out successively by the second processing unit (11) and repeated at predefined intervals: ∘ transmitting a first frame (21), which contains a reference time, to the electricity meter via the second port (15) using a serial link; ∘ configuring the second port (15) to operate in a pulse-generation mode; ∘ transmitting a pulse (23), which specifies a synchronisation time, to the electricity meter via the second port (15); ∘ reconfiguring the second port so as to communicate via the second port using the serial link.

12. Synchronisation method according to claim 11, wherein the pulse (23) has a defined duration with an accuracy of + / - 1 ms.

13. Synchronisation method according to any of claims 11 or 12, wherein the second steps further comprise the step, following the transmission of the first frame (21), of waiting to receive a second frame (22), which contains an acknowledgement message, via the second port (15) before configuring the second port (15) to operate in the pulse-generation mode.

14. Modem (2) comprising a second processing unit (11) which comprises a second port (15) and in which the second steps of the synchronisation method according to any of claims 11 to 13 are carried out.

15. Computer program comprising instructions that cause the second processing unit (11) of the modem (2) according to claim 14 to execute the second steps of the synchronisation method according to any of claims 11 to 13.

16. Computer-readable storage medium on which the computer program according to claim 15 is stored.

17. System (0) comprising an electricity meter (1) according to any of claims 7 or 8 and a modem (2) according to claim 14.