Looseness monitoring device and method for borehole sensor, terminal and storage medium

By integrating a loose monitoring device of a three-axis accelerometer and main control module on the drilling sensor, the acceleration data is monitored and analyzed in real time, the loosening problem caused by the collapse of the drilling sensor is solved, real-time early warning and data stability are achieved, and the reliability and real-time nature of the monitoring system are improved.

CN120119971APending Publication Date: 2025-06-10SHANDONG ENERGY GRP CO LTD +1
View PDF 0 Cites 0 Cited by

Patent Information

Application Number
CN202510434267.X
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2025-04-08
Publication Date
2025-06-10

AI Technical Summary

Technical Problem

Drilling sensors are prone to collapse of holes under long-term geological stress, causing the sensor to detach from the hole wall, thereby causing interruption or distortion of monitoring signals. The existing technology lacks effective monitoring methods.

Method used

Design a loose monitoring device for drilling sensors, including a three-axis accelerometer, a main control module, a voltage stabilization conversion circuit, a warning light and a power supply module. The three-axis accelerometer is used to monitor the acceleration changes of the sensor in real time. The main control module analyzes the data and judges the looseness, and lights up the warning light for early warning.

Benefits of technology

Real-time monitoring of the looseness of the drilling sensor, timely warning is issued, avoiding interruption or distortion of monitoring data, and improving the reliability and real-timeness of the monitoring system.

✦ Generated by Eureka AI based on patent content.

Smart Images

  • Figure CN120119971A_ABST
    Figure CN120119971A_ABST
Patent Text Reader

Abstract

The invention belongs to the technical field of drilling monitoring equipment, and particularly relates to a drilling sensor looseness monitoring device and method, a terminal and a storage medium, and the drilling sensor looseness monitoring device comprises a triaxial accelerometer, a main control module, a voltage stabilization conversion circuit, a warning lamp and a power supply module for supplying power to the whole device; the three-axis accelerometer is installed on the drilling sensor, the output end of the three-axis accelerometer is connected to the input end of the main control module, the warning lamp is connected to the output end of the main control module, the main control module is in communication connection with the upper computer, and the power module supplies power to the three-axis accelerometer and the main control module through the voltage stabilization conversion circuit. By integrating the three-axis accelerometer, the loosening condition of the drilling sensor can be monitored in real time. Once the sensor is loosened, the triaxial accelerometer can quickly capture the abnormal change of the acceleration, data analysis is carried out through the main control module, and an early warning signal is sent out in time, so that the problem of monitoring data interruption or distortion caused by the loosening of the sensor is effectively avoided.
Need to check novelty before this filing date? Find Prior Art

Description

Technical Field

[0001] The present invention belongs to the technical field of borehole monitoring equipment, and particularly relates to a loosening monitoring device, method, terminal and storage medium for a borehole sensor. Background Art

[0002] In the fields of geological exploration, mining and civil engineering, borehole sensors, as an important monitoring tool, are widely used in aspects such as the stability of underground structures, the dynamics of groundwater and the early warning of geological disasters. However, the long-term underground working environment poses severe challenges to borehole sensors. In particular, the problem of borehole collapse has become a key factor affecting the stability of sensors and the accuracy of monitoring data.

[0003] Borehole collapse means that the borehole collapses or deforms under the action of long-term geological stress, which may cause the sensor originally closely attached to the hole wall to gradually become detached, resulting in the interruption or distortion of the monitoring signal. Since the borehole is usually located deep underground with a complex environment and is difficult to directly observe, once the sensor becomes detached from the hole wall, it is often difficult to detect in time, thus missing the best opportunity to take remedial measures. This will not only lead to the loss of monitoring data, but also may cause misjudgment of the stability assessment of underground structures, posing a serious threat to engineering safety.

[0004] At present, although there are various borehole sensors on the market, most of them lack effective monitoring means for the loosening of sensors caused by borehole collapse. Once the sensor becomes loose, it is often necessary to wait until the monitoring data shows obvious anomalies or completely fails before the problem can be detected indirectly through an indirect method. This not only increases the maintenance cost, but also greatly reduces the reliability and real-time performance of the monitoring system. Summary of the Invention

[0005] In view of the above deficiencies of the prior art, the present invention provides a loosening monitoring device, method, terminal and storage medium for a borehole sensor to solve the above technical problems.

[0006] In a first aspect, the present invention provides a loosening monitoring device for a borehole sensor, including a triaxial accelerometer, a main control module, a voltage stabilization conversion circuit, a warning light and a power supply module for supplying power to the entire device; The triaxial accelerometer is installed on the borehole sensor, the output end of the triaxial accelerometer is connected to the input end of the main control module, the warning light is connected to the output end of the main control module, the main control module is communicatively connected to the host computer, and the power supply module supplies power to the triaxial accelerometer and the main control module through the voltage stabilization conversion circuit.

[0007] A further improvement of this technical solution is that the triaxial accelerometer adopts a triaxial accelerometer with the model SNJ-6000.

[0008] A further improvement of this technical solution is that the main control module uses a single-chip microcomputer with the model of STM32F103C8T6.

[0009] A further improvement of this technical solution is that the voltage stabilization conversion circuit includes a 12V-to-5V circuit and a 5V-to-3.3V circuit. The input end of the 12V-to-5V circuit is connected to the power supply module, the output end of the 12V-to-5V circuit is connected to the input end of the 5V-to-3.3V circuit, and the output end of the 5V-to-3.3V circuit is connected to the power supply end of the three-axis accelerometer and the power supply end of the main control module.

[0010] A further improvement of this technical solution is that the 12V-to-5V circuit includes a zener diode D1, a capacitor C1, a voltage regulator chip U1, a zener diode D2, an inductor L1, a capacitor C2, and a capacitor C3; The positive pole of the zener diode D1 is connected to the 12V power supply in the power supply module, the negative pole of the zener diode D1 is connected to the input pin of the voltage regulator chip U1 and the first end of the capacitor C1, the second end of the capacitor C1 is grounded, the voltage feedback pin of the voltage regulator chip U1 is connected to the 5.5V output end of the circuit, the output pin of the voltage regulator chip U1 is connected to the negative pole of the zener diode D2 and the first end of the inductor L1, the second end of the inductor L1 is connected to the first end of the capacitor C2, the first end of the capacitor C3, and the 5.5V output end of the circuit, and the positive pole of the zener diode D2, the second end of the capacitor C2, and the second end of the capacitor C3 are all grounded.

[0011] A further improvement of this technical solution is that the 5V-to-3.3V circuit includes a capacitor C4, a voltage regulator chip U2, a light-emitting diode D3, a capacitor C5, and a resistor R1; The first end of the capacitor C4 and the input end of the voltage regulator chip U2 are both connected to the voltage feedback pin of the voltage regulator chip U1, the second end of the capacitor C4 is grounded, the output pin of the voltage regulator chip U2 is connected to the 3.3V output end of the circuit, the positive pole of the light-emitting diode D3, and the first end of the capacitor C5, the second end of the capacitor C5 is grounded, and the negative pole of the light-emitting diode D3 is grounded through the resistor R1.

[0012] A further improvement of this technical solution is that it further includes a signal converter and an RS485 communication line, and the main control module is sequentially connected to the upper computer through the signal converter and the RS485 communication line.

[0013] In a second aspect, the present invention provides a monitoring method for a loosening monitoring device of a drilling sensor based on any one of the above, including: The three-axis accelerometer monitors the loosening of the drilling sensor and uploads the monitored data to the main control module; The main control module analyzes the received monitoring data, determines whether the drilling sensor has an acceleration greater than the preset acceleration, and makes a statistic; If so, increment the number of times the drilling sensor has an acceleration greater than the preset acceleration by one, and record the corresponding occurrence time; The main control module determines whether the drilling sensor has a preset number of cases of acceleration greater than the preset acceleration within one hour; If so, the main control module determines that the drilling sensor is loose and lights up the warning light.

[0014] In a third aspect, a terminal is provided, including: A processor and a memory, wherein, The memory is used to store a computer program, The processor is used to call and run the computer program from the memory, so that the terminal executes the method of the above terminal.

[0015] In a fourth aspect, a computer storage medium is provided. Instructions are stored in the computer-readable storage medium, and when it runs on a computer, the computer is made to execute the methods described in the above aspects.

[0016] The beneficial effects of the present invention are as follows: Real-time monitoring and early warning: By integrating a three-axis accelerometer, the present invention can monitor the loosening of the drilling sensor in real time. Once the sensor becomes loose, the three-axis accelerometer can quickly capture the abnormal change in acceleration, and through data analysis by the main control module, an early warning signal is sent in time to light up the warning light, thus effectively avoiding the problem of interruption or distortion of monitoring data caused by sensor loosening.

[0017] Improve the reliability and real-time performance of the monitoring system: The monitoring device of the present invention can issue an early warning at the initial stage of sensor loosening by intelligently judging and analyzing acceleration data, greatly advancing the time of problem discovery, providing a sufficient time window for taking remedial measures. This not only reduces the maintenance cost but also significantly improves the reliability and real-time performance of the monitoring system.

[0018] Flexible power management: Through the voltage stabilization conversion circuit, the present invention can ensure the stable operation of the three-axis accelerometer and the main control module under different voltage requirements. At the same time, the design of the power module also takes into account the particularity of the underground environment to ensure the continuous power supply of the entire device.

[0019] Convenient remote monitoring: The present invention also includes a signal converter and an RS485 communication line, enabling the main control module to communicate remotely with the upper computer. In this way, users can monitor the status of the drilling sensor in real time through the upper computer, greatly improving the convenience and efficiency of the monitoring work.

[0020] In addition, the design principle of the present invention is reliable, the structure is simple, and it has a very wide application prospect. Description of the Drawings

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 It is a schematic block diagram of a device according to an embodiment of the present invention.

[0023] Figure 2 It is a schematic diagram of the installation position of the monitoring device of the present invention.

[0024] Figure 3 It is a schematic diagram of the voltage stabilization conversion circuit.

[0025] Figure 4 It is a schematic flowchart of a method according to an embodiment of the present invention.

[0026] Figure 5 It is a schematic diagram of the structure of a terminal provided by an embodiment of the present invention.

[0027] 110 is a three-axis accelerometer, 120 is a main control module, 130 is a voltage stabilization conversion circuit, 140 is a power supply module, and 150 is a host computer. Specific embodiments

[0028] To make the objectives, features, and advantages of the present invention more obvious and understandable, the following will clearly and completely describe the technical solutions in the present invention in conjunction with the accompanying drawings in the specific embodiments of the present invention. Obviously, the embodiments described below are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in this patent, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of this patent.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs. The terms used in the description of the present invention in this specification are only for the purpose of describing specific embodiments, and are not intended to limit the present invention.

[0030] The following explains the key terms that appear in the present invention.

[0031] RS485, the full name of which is Electronic Industry Association (EIA) Standard RS-485, means Electronic Industry Association (EIA) Standard RS-485 in Chinese. It is a standard that defines the electrical characteristics of drivers and receivers in balanced digital multi-point systems. It was published by the Electronic Industry Association (EIA) in 1983 and later revised by the Telecommunications Industry Association (TIA) and named TIA / EIA-485-A, also known as TIA-485-A, ANSI / TIA / EIA-485 or TIA / EIA-485. Among them, "RS" is the abbreviation of "Recommended Standard", which means "recommended standard", and "485" is an identification number used to distinguish it from other interface standards. RS485 is widely used in industries such as industrial control, power communication, and intelligent instruments. It has the characteristics of long-distance transmission, strong anti-noise ability, and support for multi-point data communication.

[0032] like Figure 1 As shown, the present invention provides a looseness monitoring device for a drilling sensor, comprising a three-axis accelerometer, a main control module, a voltage stabilizing conversion circuit, a warning light and a power module for supplying power to the entire device; the three-axis accelerometer is installed on the drilling sensor, the output end of the three-axis accelerometer is connected to the input end of the main control module, the warning light is connected to the output end of the main control module, the main control module is communicatively connected to a host computer, and the power module supplies power to the three-axis accelerometer and the main control module through the voltage stabilizing conversion circuit.

[0033] Among them, the three-axis accelerometer adopts the SNJ-6000 three-axis accelerometer; the main control module adopts the STM32F103C8T6 single-chip microcomputer, and the host computer adjusts the sensitivity parameters of the three-axis accelerometer through the single-chip microcomputer so that the three-axis accelerometer can only detect the loose switch trigger and avoid normal seismic wave triggering.

[0034] like Figure 2 As shown in the figure, since the wall of the oil filling pipeline where the drilling sensor is installed is made of metal, the power supply line of the monitoring circuit (including the three-axis accelerometer, the main control module and the voltage stabilization conversion circuit) can use the wall of the oil filling pipeline as a loop, and a single-core communication cable can be built into the pipeline. In addition, the device also includes a signal converter and an RS485 communication line, and the main control module is connected to the host computer through the signal converter and the RS485 communication line in turn.

[0035] Specifically, the voltage stabilization conversion circuit includes a 12V-to-5V circuit and a 5V-to-3.3V circuit. The input terminal of the 12V-to-5V circuit is connected to the power supply module, the output terminal of the 12V-to-5V circuit is connected to the input terminal of the 5V-to-3.3V circuit, and the output terminal of the 5V-to-3.3V circuit is connected to the power supply terminal of the triaxial accelerometer and the power supply terminal of the main control module.

[0036] As Figure 3 shown, the 12V-to-5V circuit includes a voltage stabilizing diode D1, a capacitor C1, a voltage stabilizing chip U1, a voltage stabilizing diode D2, an inductor L1, a capacitor C2, and a capacitor C3; the positive electrode of the voltage stabilizing diode D1 is connected to the 12V power supply in the power supply module, the negative electrode of the voltage stabilizing diode D1 is connected to the input pin of the voltage stabilizing chip U1 and the first end of the capacitor C1, the second end of the capacitor C1 is grounded, the voltage feedback pin of the voltage stabilizing chip U1 is connected to the 5.5V output terminal of the circuit, the output pin of the voltage stabilizing chip U1 is connected to the negative electrode of the voltage stabilizing diode D2 and the first end of the inductor L1, the second end of the inductor L1 is connected to the first end of the capacitor C2, the first end of the capacitor C3, and the 5.5V output terminal of the circuit, and the positive electrode of the voltage stabilizing diode D2, the second end of the capacitor C2, and the second end of the capacitor C3 are all grounded.

[0037] Furthermore, the 5V-to-3.3V circuit includes a capacitor C4, a voltage stabilizing chip U2, a light emitting diode D3, a capacitor C5, and a resistor R1; the first end of the capacitor C4 and the input terminal of the voltage stabilizing chip U2 are both connected to the voltage feedback pin of the voltage stabilizing chip U1, the second end of the capacitor C4 is grounded, the output pin of the voltage stabilizing chip U2 is connected to the 3.3V output terminal of the circuit, the positive electrode of the light emitting diode D3, and the first end of the capacitor C5, the second end of the capacitor C5 is grounded, and the negative electrode of the light emitting diode D3 is grounded through the resistor R1.

[0038] As Figure 4 shown, the present invention provides a method for monitoring the looseness of a drilling sensor, including: Step 410, the triaxial accelerometer monitors the looseness of the drilling sensor and uploads the monitored data to the main control module; Step 420, the main control module analyzes the received monitoring data, determines whether the drilling sensor has a situation where the acceleration is greater than the preset acceleration, and makes a statistic; if so, go to step 430; Step 430, increment the number of times the drilling sensor has an acceleration greater than the preset acceleration by one, and record the corresponding occurrence time; Step 440, the main control module determines whether the drilling sensor has a preset number of situations where the acceleration is greater than the preset acceleration within one hour; if so, go to step 450; Step 450, the main control module determines that the drilling sensor is loose and lights up the warning light.

[0039] Specifically, if the situation where the acceleration is greater than the preset acceleration occurs three times within one hour, the main control module determines that the drilling sensor is loose and lights up the warning light to remind the maintenance personnel to conduct further inspections.

[0040] Figure 5 FIG. 500 is a schematic structural diagram of a terminal 500 provided by an embodiment of the present invention, and the terminal 500 can be used to execute the method for monitoring the looseness of a drilling sensor provided by the embodiment of the present invention.

[0041] Among them, the terminal 500 may include: a processor 510, a memory 520, and a communication module 530. These components communicate through one or more buses. Those skilled in the art can understand that the structure of the server shown in the figure does not constitute a limitation to the present invention. It can be a bus structure, a star structure, and may also include more or fewer components than shown in the figure, or combine certain components, or have different component arrangements.

[0042] Among them, the memory 520 can be used to store the execution instructions of the processor 510. The memory 520 can be implemented by any type of volatile or non-volatile storage terminal or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, a magnetic disk, or an optical disk. When the execution instructions in the memory 520 are executed by the processor 510, the terminal 500 can execute some or all of the steps in the above method embodiments.

[0043] The processor 510 is the control center of the storage terminal, connects various parts of the entire electronic terminal through various interfaces and lines, and executes various functions and / or processes data of the electronic terminal by running or executing software programs and / or modules stored in the memory 520, and calling the data stored in the memory. The processor can be composed of an integrated circuit (IC). For example, it can be composed of a single packaged IC, or can be composed of connecting multiple packaged ICs with the same or different functions. For example, the processor 510 may only include a central processing unit (CPU). In the embodiment of the present invention, the CPU can be a single operation core or can include multiple operation cores.

[0044] The communication module 530 is used to establish a communication channel so that the storage terminal can communicate with other terminals. Receive user data sent by other terminals or send user data to other terminals.

[0045] The present invention also provides a computer storage medium. The computer storage medium can store a program which, when executed, can include some or all of the steps in the various embodiments provided by the present invention. The storage medium can be a magnetic disk, an optical disk, a read-only memory (ROM), a random access memory (RAM), or the like.

[0046] Those skilled in the art can clearly understand that the technology in the embodiments of the present invention can be implemented by means of software plus a necessary general hardware platform. Based on such an understanding, the technical solutions in the embodiments of the present invention, in essence, or the part that contributes to the prior art can be embodied in the form of a software product. The computer software product is stored in a storage medium such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, etc., which can store program codes, and includes several instructions for causing a computer terminal (which can be a personal computer, a server, or a second terminal, a network terminal, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention.

[0047] For the same or similar parts among the various embodiments in this specification, reference can be made to each other. In particular, for the terminal embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and reference can be made to the descriptions in the method embodiments for the relevant parts.

[0048] In the several embodiments provided by the present invention, it should be understood that the disclosed systems and methods can be implemented in other ways. For example, the system embodiments described above are merely illustrative. For example, the division of the modules is only a logical function division. In actual implementation, there can be other division methods. For example, multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces. The indirect couplings or communication connections of the systems or modules can be in electrical, mechanical, or other forms.

[0049] The modules described as separate components may or may not be physically separated. The components shown as modules may or may not be physical modules, that is, they can be located in one place or distributed to multiple network modules. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0050] In addition, in each embodiment of the present invention, each functional module may be integrated into one processing module, may exist separately physically for each module, or two or more modules may be integrated into one module.

[0051] Although the present invention has been described in detail by referring to the accompanying drawings and in combination with the preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, those of ordinary skill in the art can make various equivalent modifications or substitutions to the embodiments of the present invention, and these modifications or substitutions should all be within the scope of the present invention. / Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention.

Claims

1. A looseness monitoring device for a drilling sensor, characterized in that: It includes a three-axis accelerometer, a main control module, a voltage stabilization conversion circuit, a warning light, and a power module for supplying power to the entire device; The triaxial accelerometer is installed on the drilling sensor, the output end of the triaxial accelerometer is connected to the input end of the main control module, the warning light is connected to the output end of the main control module, the main control module is connected to the host computer for communication, and the power supply module supplies power to the triaxial accelerometer and the main control module through a voltage stabilizing conversion circuit.

2. The looseness monitoring device of a drilling sensor according to claim 1, characterized in that: The three-axis accelerometer adopts the SNJ-6000 three-axis accelerometer.

3. The looseness monitoring device of a drilling sensor according to claim 1, characterized in that: The main control module uses a single-chip microcomputer model STM32F103C8T6.

4. The looseness monitoring device of a drilling sensor according to claim 1, characterized in that: The voltage stabilizing conversion circuit includes a 12V to 5V circuit and a 5V to 3.3V circuit. The input end of the 12V to 5V circuit is connected to the power module, the output end of the 12V to 5V circuit is connected to the input end of the 5V to 3.3V circuit, and the output end of the 5V to 3.3V circuit is connected to the power end of the three-axis accelerometer and the power end of the main control module.

5. The looseness monitoring device of a drilling sensor according to claim 4, characterized in that: The 12V to 5V circuit includes a voltage stabilizing diode D1, a capacitor C1, a voltage stabilizing chip U1, a voltage stabilizing diode D2, an inductor L1, a capacitor C2 and a capacitor C3; The positive electrode of the voltage regulator diode D1 is connected to the 12V power supply in the power module, the negative electrode of the voltage regulator diode D1 is connected to the input pin of the voltage regulator chip U1 and the first end of the capacitor C1, the second end of the capacitor C1 is grounded, the voltage feedback pin of the voltage regulator chip U1 is connected to the 5.5V output end of the circuit, the output pin of the voltage regulator chip U1 is connected to the negative electrode of the voltage regulator diode D2 and the first end of the inductor L1, the second end of the inductor L1 is connected to the first end of the capacitor C2, the first end of the capacitor C3 and the 5.5V output end of the circuit, and the positive electrode of the voltage regulator diode D2, the second end of the capacitor C2 and the second end of the capacitor C3 are all grounded.

6. The looseness monitoring device of a drilling sensor according to claim 5, characterized in that: The 5V to 3.3V circuit includes capacitor C4, voltage regulator chip U2, light emitting diode D3, capacitor C5 and resistor R1; The first end of capacitor C4 and the input end of voltage stabilizing chip U2 are both connected to the voltage feedback pin of voltage stabilizing chip U1, the second end of capacitor C4 is grounded, the output pin of voltage stabilizing chip U2 is connected to the 3.3V output end of the circuit, the positive electrode of light-emitting diode D3 and the first end of capacitor C5, the second end of capacitor C5 is grounded, and the negative electrode of light-emitting diode D3 is grounded through resistor R1.

7. The looseness monitoring device of a drilling sensor according to claim 1, characterized in that: It also includes a signal converter and an RS485 communication line. The main control module is connected to the host computer through the signal converter and the RS485 communication line in turn.

8. A monitoring method for a looseness monitoring device of a drilling sensor according to any one of claims 1 to 7, characterized in that: include: The three-axis accelerometer monitors the looseness of the drilling sensor and uploads the monitored data to the main control module; The main control module analyzes the received monitoring data, determines whether the drilling sensor has a situation where the acceleration is greater than the preset acceleration, and makes statistics; If yes, then the number of times the drilling sensor appears to have an acceleration greater than the preset value is increased by one, and the corresponding occurrence time is recorded; The main control module determines whether the drilling sensor has a preset acceleration greater than a preset number of times within one hour; If so, the main control module determines that the drilling sensor is loose and turns on the warning light.

9. A terminal, characterized in that: include: processor; A memory for storing execution instructions of the processor; Wherein, the processor is configured to execute the method of claim 8.

10. A computer-readable storage medium storing a computer program, characterized in that: When the program is executed by a processor, the method according to claim 8 is implemented.