CN100492024C - Full-automatic hook type ammeter - Google Patents

Abstract

A full-automatic hook type ammeter comprises a measuring main body, a display and a single control key are arranged on the measuring main body, a test probe is inserted into the measuring main body, and a current clamp is arranged at the upper end of the measuring main body and used for containing a current carrier; the full-automatic hook-type ammeter is characterized by further comprising an automatic judging and switching mode, wherein the measuring main body judges and selects the external input condition when the ammeter is started, and the measuring main body has the measurement of an alternating current mode and a direct current mode.

Description

Automatic hook meter

technical field

The invention relates to a fully automatic hook-type electric meter, in particular to a full-automatic hook-type electric meter which can be hooked to any online at will. In addition to AC and DC voltage, resistance or diode measurement modes, it can also measure AC and DC current modes.

Background technique

Existing electricity meters can be roughly divided into two types: electronic LCD liquid crystal display and mechanical meter. In addition to the difference in the display of the meter on the common models, they are all equipped with an operation knob for multi-segment function switching, and there is a switch next to it. The function mark allows users to manually adjust and switch according to the items they want to test, and select the relevant measurement properties and symbols in the gears of the size range to be measured. Appropriate judgment ability can be used. If beginners or unfamiliar with the operation, the value of the measured value will be wrong due to inaccurate gear selection, or even seriously used in high voltage or high current selection, the wrong position will damage the meter body and cause damage. endanger the operator's own safety.

Although there are automatic meters on the market, which can solve the above-mentioned shortcomings of unfamiliarity with the adjustment and measurement of electricity, their basic functions only have three automatic measurement modes for AC voltage, DC voltage or resistance measurement, and cannot be used for hook-type switching, The application of automatic measurement of DC current greatly limits the available measurement range.

Contents of the invention

The main purpose of the present invention is to provide a device that can be hooked to any line at will, has automatic detection and switching options, and can be used for AC and DC voltage, resistance or diode measurement modes, as well as AC and DC current mode measurement. Fully automatic hook meter.

The secondary purpose of the present invention is to provide a safe, accurate and suitable measurement priority and electricity measurement property judgment mode for the aforementioned automatic hook-type electric meter. The user only needs to turn on the power of the electric meter without performing other operations. Get accurate power readings from the display.

Another object of the present invention is to provide a single-key operation that can simultaneously have a freeze-frame instantaneous mode, an automatic freeze-frame instantaneous mode, and a maximum value/minimum value recording mode, so as to facilitate the measurement of electric power values and be easy to interpret. The electric meter, and press the button and include actions such as the DC current remanence zero mode and the cancellation of the automatic shutdown mode.

Another object of the present invention is to provide an instantaneous mode that can automatically freeze the frame when measuring the current, so that the user can freeze the stable current reading and display it on the display without pressing the control key when measuring the current. superior.

Another object of the present invention is to provide an automatic display backlight mode that automatically turns on and off the display backlight according to the ambient brightness, so that users can easily see the readings on the display even in an environment with poor brightness.

Another object of the present invention is to provide a safety warning mode, which provides the user with a dangerous voltage or current measured when using the freeze frame instantaneous mode and the maximum/minimum value recording mode, and the danger When the signal is different from the signal displayed on the display, it can automatically issue a warning to warn the user that such an operation action is dangerous, making the operation safer.

In order to achieve the above-mentioned purpose, a fully automatic hook-type electric meter provided by the present invention includes a measuring main body, which is provided with a display and a single control key, the main body is used for inserting test probes, and the upper end of the main body is provided There is a current clip for accommodating a carrier fluid; it is characterized in that the fully automatic hook-type meter also includes:

An automatic judgment switching mode, which is selected by the measurement subject according to the external input conditions when starting up, and has the measurement of DC voltage mode, AC voltage mode, resistance mode, diode mode, and AC and DC current modes; and

A priority detection mode, in the automatic judgment switching mode, the input of the test probe is the priority, and the input of the current clamp is secondary;

Among them, when the automatic hook-type meter is turned on, it enters the initial setting and after detecting the battery power, first measures the DC voltage, then measures the AC voltage, and then performs the following series of judgment actions:

a: If the measured DC voltage is greater than 999.9V and the AC voltage is also greater than 999.9V, the AC/DC voltage overflow signal will be displayed; if the AC measurement value is not greater than 999.9V, only the DC voltage overflow OL signal will be displayed;

b: Assuming that the DC measurement result is between 2.1V～999.9V or between -0.5V～-999.9V, the AC voltage judgment will be performed. If the DC measurement result is greater than 999.9V, the AC voltage overflow signal will be displayed. When the AC voltage is greater than the DC voltage whose absolute value is taken, it will display the measured AC voltage and display its value, if the above judgment is otherwise, it will display the measured DC voltage and display its value;

c: If the measured DC voltage is lower than 2.1V and greater than -0.5V, and the AC voltage is between 1.0V and 999.9V, the AC voltage will be displayed. If the AC voltage is greater than 999.9V, the AC voltage overflow OL signal will be displayed. If The AC voltage is not greater than 0.9V, and if the absolute value of the DC voltage measurement result is less than or equal to 1.1V, it will automatically switch to the resistance measurement mode, and if the AC voltage is greater than 0.2V, it will automatically switch to the diode measurement mode :

d: Enter the resistance measurement mode, and if it is judged that the resistance is less than 10000 ohms, the measured resistance value will be displayed, and the resistance will be measured continuously, and the AC voltage will be measured once after every two resistance measurements. If the AC voltage measurement result is greater than or equal to 1.0V, the AC voltage will be displayed, otherwise, the resistance will be continuously measured, and if it is greater than 9999 ohms, it will jump to the diode measurement mode;

e: Enter the measurement diode mode, judge that the voltage value at both ends of the diode is between 0.3V and 0.9V, then display the measured voltage value, and jump to the current measurement mode if it is not within the range;

f: Enter the current measurement mode, measure the DC current, and then measure the AC current. If the measurement result of the DC current is greater than 999.9A and the AC current is also greater than 999.9A, the AC and DC current overflow signal will be displayed. If the AC measurement value is not greater than At 999.9A, only the DC current overflow signal is displayed;

g: Assuming that the absolute value of the DC current measurement result is between 0.6A and 999.9A, the AC current will be judged. If it is greater than 999.9A, the AC current overflow signal will be displayed. If it is not the above situation, when the AC current is greater than the DC current of the absolute value , it shows that the measured AC current is displayed and its value is displayed; otherwise, it is displayed that the measured one is DC current and its value is displayed; and

h: If the measured DC current is lower than 0.6A and greater than -0.6A, and the AC current is between 0.6A and 999.9A, it will display the AC current. If the AC current is greater than 999.9A, it will display the AC current overflow OL signal. When the current is not greater than 0.6A, the status of the resistance file overflow is displayed.

In this way, the electric meter can be controlled by a single button to automatically switch intelligently, saving the action and time of operating the electric meter, hooking the electric meter on any line to facilitate observation of the measured value improves its convenience and efficiency, and prevents the user from operating the wrong adjustment by himself. It can cause damage to the meter body and endanger its own safety, and can greatly improve the industrial safety of large current measurement applications. It also provides measurement maximum/minimum value recording mode, automatic freeze frame instantaneous mode, DC current remanence zero return mode and automatic display backlight. Mode increases the convenience of using the meter.

For the convenience of a deeper understanding of the present invention, hereby describe in detail the following by an embodiment:

Description of drawings

Fig. 1 is the three-dimensional appearance diagram of the embodiment of the automatic hook-type electric meter of the present invention;

Fig. 2 is a flow chart of automatically judging the switching mode collocation priority detection mode in the embodiment of the present invention;

Fig. 3 is a control flow chart of a single control key according to an embodiment of the present invention;

Fig. 4 is the flow chart when measuring the embodiment of the present invention;

FIG. 5 is an internal circuit diagram of an embodiment of the present invention.

Explanation of reference numerals: 1-measurement main body; 11-display; 12-single control key; 13-test probe; 14-current clip; 15-carrier fluid; 16-buzzer; 2-automatic judgment switching mode; 3-priority detection mode; 80-constant voltage circuit; 81-backlight circuit; 82-DC filter circuit; 90-attenuation circuit; 91-protection circuit; 92-constant current circuit; 93-switching circuit; 94-current sensing circuit ; 95-instrument and display controller; 96-resistance detection circuit; 97-AC rectification filter circuit; 98-analog/digital converter.

Detailed ways

Please refer to FIGS. 1 to 5 . The content of the drawings is an embodiment of the automatic hook-type electric meter of the present invention, which mainly includes a measurement body 1 , an automatic judgment switching mode 2 and a priority detection mode 3 .

The measuring main body 1 is provided with a display 11 and a single control key 12 , the measuring main body 1 is used for inserting the test probe 13 , and the upper end of the measuring main body 1 is provided with a current clip 14 for accommodating a carrier fluid 15 .

The automatic judgment switching mode 2 is judged and selected by the measurement main body 1 according to the external input conditions when starting up, and has the measurement of AC, DC current, DC voltage mode, AC voltage mode, resistance mode and diode mode, and the priority In the detection mode 3 and the automatic judgment switching mode 2, the input of the test probe 13 is prioritized, and the input of the current clamp 14 is secondary (as shown in FIG. 2 ).

In this way, the measurement main body 1 can be controlled by a single control key 12 to achieve the function of automatic intelligent switching, saving the action and time of operating the meter, and using the current clip 14 to hook the meter on any line to facilitate observation of the measured value and improve its convenience and It can improve the efficiency and prevent the user from making wrong adjustments by himself, causing damage to the meter body and endangering his own safety. It can also greatly improve the industrial safety of high-current measurement applications.

When the present invention is implemented, a buzzer 16 can be provided in the measuring main body 1 to provide a sound in response to the measured state in a timely manner. When the measuring main body 1 is manufactured, the bottom end can be made narrower than the top end to make the three-purpose electric meter Easy to hold, the optimal design of the size of each part allows the three-purpose electric meter to be operated with one hand, so that the single control key 12 can be started by either hand holding the three-purpose electric meter, and the single control key 12 can also be used as a freeze frame Instantaneous mode, canceling the action of automatic freezing instantaneous mode, measuring the maximum value/minimum value recording mode, the start-up control of the DC current residual magnetism return mode, etc., and canceling the automatic shutdown mode, that is, the single control key 12 is in the shutdown state It is used to start the three-purpose electric meter. If the single control key 12 is pressed and released immediately when shutting down, the automatic shutdown mode will be started and the power will be turned on. The triple function of the magnetic zero mode and shutting down the meter can be used to keep the measurement results on the display when the freeze frame instantaneous mode is executed, and the current can be clamped by 14 when the dc current remanence return mode is used to measure the dc current. To eliminate the residual magnetism effect, press the single control button 12 for more than 3 seconds in the power-on state, it will be turned off, when it exceeds 1 second, it will execute the DC current residual magnetism zero mode, and if it is less than 1 second, it will execute the freeze-frame instantaneous mode, press it again Then the Freeze Momentary mode is cancelled.

In the state of starting the automatic shutdown mode, if the single control key 12 is pressed after the automatic freeze-frame instantaneous mode is activated when measuring current, the automatic freeze-frame instantaneous mode will be converted into the freeze-frame instantaneous mode, and the measurement results displayed on the screen will not change , when it exceeds 1 second, it will execute the DC current remanence zero mode, and when it exceeds 3 seconds, it will shut down. Press again to cancel Freeze Momentary mode.

If the single control key 12 is pressed and pressed continuously for more than 2 seconds when shutting down, the automatic shutdown mode will be canceled and the machine will be turned on. After that, the single control key 12 will also have the functions of measuring the maximum value/minimum value recording mode, DC current zeroing and turning off the electric meter. Triple function, when measuring AC voltage, DC voltage, AC current or DC current mode, press the control key 12 to execute the maximum/minimum value recording mode, which can be used to fix the meter at AC voltage, DC In voltage, AC current or DC current mode, and record the maximum value and minimum value measured after starting the measurement maximum value/minimum value recording mode, and the recording result or real-time measurement result can be switched and displayed on the display. When it is turned on and pressed for more than 3 seconds, it will be turned off. When it is more than 1 second, it will execute the DC current residual magnetism zeroing mode. If it is less than 1 second, it will execute the measurement maximum/minimum value recording mode.

In the maximum/minimum value recording mode, each time the single control key 12 is pressed, the real-time measured value, the maximum measured value and the minimum measured value will be displayed sequentially. When it exceeds 1 second, it is the DC current remanence zero mode, and when it exceeds 3 seconds, it is turned off.

Wherein, the measurement main body 1 will beep once when the freeze frame instantaneous mode is started and the display 11 will display the "HOLD" symbol.

In the state of starting the automatic shutdown mode when starting up, when measuring the current, when a value greater than or equal to a certain set current value is measured, it is called the instant of automatic freeze, and the stability of the minimum current measurement value (such as 3A) It will automatically start when the current is flowing. When starting, it will beep three times continuously and the display 11 will display two symbols "AUTO" and "HOLD". The auto-freeze instantaneous mode will switch to the freeze-frame instantaneous mode and there will be a beep. At this time, the screen remains unchanged. If the current is stable and the current value differs from the value on the display 11 by more than 0.2A, restart the automatic freeze frame instantaneous mode to keep displaying new measurement results; When it is less than the auto-freeze transient minimum current measurement value (such as 3A) or is an unsteady current, the auto-freeze transient mode will be automatically canceled after 5 seconds; after the auto-freeze transient mode is activated, it will still measure whether there is a signal from the test probe 13 , if there is, immediately leave the automatic freeze-frame instantaneous mode and switch to the appropriate mode for measurement and display.

In the state of canceling the automatic power-off mode, and when measuring AC and DC voltage or AC and DC current, if the button is pressed for less than 1 second, the maximum value/minimum value recording mode will be started, and there will be a beep and the display 11 when starting The "RECORD" symbol is displayed, and then the gauge will continue to record the maximum and minimum values measured after entering the maximum value/minimum value recording mode, and the current measurement value will be displayed on the display 11 at the same time; press a single control key After 12, the recorded maximum value and "MAX" symbol will be displayed and one beep will be displayed. Press again and the recorded minimum value and "MIN" symbol will be displayed and one beep will be displayed. Press again to display the current measurement result and "RECORD" symbol It beeps once, and switches in this way; if it is pressed for more than 1 second, it will execute the DC current residual magnetism zeroing mode, which can eliminate the residual magnetism effect generated by the current clamp 14 when measuring DC current, and display "DC" during execution , "0.0", "A", "ZERO" and other symbols for 2 seconds to indicate the execution of this action and leave the measurement maximum/minimum value recording mode, and it will be turned off when it exceeds 3 seconds.

And when the user still does not operate after 20 minutes from the last operation, and the automatic shutdown mode is activated, the meter will automatically shut down.

The present invention can measure six modes: a DC voltage mode, an AC voltage mode, a DC current mode, an AC current mode, a diode mode, and an automatic judgment switching mode 2 of the resistance mode, which is automatically judged and switched by the meter itself , when the three-purpose electric meter automatically judges the switching mode 2, the priority detection mode 3 will take the input signal of the test probe 13 as the main, and the input signal of the current clip 14 as the secondary, that is to say, in the DC voltage mode, AC When the voltage mode, resistance mode or diode mode test probe 13 can measure a signal, it will display the relative value of voltage, resistance or diode, and only display the current value measured by the current clip 14 when there is no signal. When the current clamp 14 can not measure the current, the overflow state of the resistance file is displayed.

According to the above characteristics, when measuring voltage, resistance or diode, the user can hook the ammeter to any line to observe the measured value conveniently. Regardless of whether the line has current passing through it, the measured voltage or voltage can be displayed correctly. When measuring the current, the current can be measured by the current clamp 14 as long as the test probe 13 is open and no signal is input. Therefore, the application of this three-purpose ammeter can provide greater convenience and convenience in use than the conventional ammeter. For safety, there is no need to manually change the file measurement in order to measure different signals.

In the design of the present invention, when the single control key 12 is activated, it is preset to the voltage mode. If there is a voltage input at both ends of the test probe 13, it is judged whether the AC voltage is greater than 0.9V, whether the DC voltage is greater than 2.0V, or whether it is less than or equal to - 0.5V, if it is determined which of the DC component and the AC component is larger, the AC or DC voltage mode with the larger matching component will be displayed on the display 11, if not, then switch to the resistance mode and judge whether the resistance to be measured at both ends of the test probe 13 is less than 10000 Ohm, if it is less than the measured resistance value, it will switch to the diode mode and judge whether the diode voltage to be tested at both ends of the test probe 13 is greater than 0.2V and less than 1.0V, if it is, it will display the measured diode voltage If not, switch to the current mode and judge whether there is current at both ends of the current clamp 14. If there is current, judge whether the AC current C is greater than 0.5A, whether the DC current is greater than 0.5A or whether it is less than -0.5A, and if so, judge the DC component Whichever is greater with the AC component, the AC or DC current pattern with the greater coincident component will be displayed on the display 11, if not, the state of the resistance file overflow will be displayed.

The more specific action mode is shown in Figure 4. When the invention is turned on, it enters the initial action setting, first detects the battery level and displays the battery level percentage, first measures the DC voltage, then measures the AC voltage, and then performs the following series of judgment actions:

a. If the measured DC voltage is greater than 999.9V and the AC voltage is also greater than 999.9V, the AC/DC voltage overflow OL signal will be displayed. If the AC measurement value is not greater than 999.9V, only the DC voltage overflow OL signal will be displayed.

b. Assuming that the DC voltage measurement result is between 2.1 ~ 999.9V or between -0.5V ~ -999.9V, the AC voltage judgment will be carried out. If it is greater than 999.9V, the AC voltage overflow OL signal will be displayed. If it is not the above situation, its AC voltage When it is greater than the DC voltage whose absolute value is taken, it will display the measured AC voltage and display its value; otherwise, it will display the measured DC voltage and display its value.

c. If the measured DC voltage is lower than 2.1V and greater than -0.5V, and the AC voltage is between 1.0V and 999.9V, the AC voltage will be displayed. If the AC voltage is greater than 999.9VAC, the AC voltage overflow OL signal will be displayed. If the AC voltage is not greater than 0.9V, and if the absolute value of the DC voltage measurement result is less than or equal to 1.1V, it will automatically switch to the resistance measurement mode, and if it is greater than 0.2V, it will automatically switch to the diode measurement mode. model.

d. Enter the resistance measurement mode, and if it is judged that the resistance is less than 10000 ohms, the measured resistance value will be displayed, and the resistance will be measured continuously, and the AC voltage will be measured once after every two resistance measurements. If the AC voltage measurement result is greater than or equal to 1.0V, the AC voltage will be displayed, otherwise, the resistance will be continuously measured, and if it is greater than 9999 ohms, it will jump to the diode measurement mode.

e. Enter the diode measurement mode, judge that the voltage value at both ends of the diode is between 0.3 ~ 0.9V, then display the measured voltage value, if not within the range, jump to the current measurement mode.

f. Enter the current measurement mode, measure the DC current, and then measure the AC current. If the measurement result shows that the DC current is greater than 999.9A and the AC current is also greater than 999.9A, the AC and DC current overflow OL signal will be displayed. If the AC measurement value is not When it is greater than 999.9A, only the DC current overflow OL signal is displayed.

g. Assume that the absolute value of the DC current measurement result is between 0.6 and 999.9A, then judge the AC current. If it is greater than 999.9A, it will display the AC current overflow OL signal. If it is not the above situation, when the AC current is greater than the absolute value of the DC current , it will display the measured AC current and display its value, otherwise it will display the measured DC current and display its value.

h. If the measured DC current is lower than 0.6A and greater than -0.6A, and the AC current is between 0.6A and 999.9A, it will display the AC current. If the AC current is greater than 999.9A, it will display the AC current overflow OL signal. When the current is not greater than 0.6A, it will display the Ω "OL" status of the resistance file overflow.

The present invention is designed to comply with the priority detection mode 3, so it will still measure whether the test probe 13 has a signal in the DC current and AC current modes, and switch to the appropriate mode for measurement and display if there is.

Please refer to Figures 1 and 5, which are the circuit system architecture of the present invention, wherein, in addition to the aforementioned display 11, buzzer 16 and single control key 12, it further includes an attenuation circuit 90 coupled with the test probe 13 and A protection circuit 91, a constant current circuit 92, a switching circuit 93, a current sensing circuit 94, an instrument and display controller 95, a resistance detection circuit 96, two AC rectification and filtering circuits 97, an analog/digital conversion 98, a constant voltage circuit 80, two DC filter circuits 82, and a backlight circuit 81.

The attenuation circuit 90 provides a regulated input voltage to the aforementioned DC filter circuit 82 and AC rectification filter circuit 97 and then outputs to the switching circuit 93, the switching circuit 93 is controlled by the instrument and display controller 95, according to the current measured mode Output the corresponding voltage, current, diode or resistance signal to the analog/digital converter 98 .

The constant current circuit 92 provides a test current to the protection circuit 91 in resistance mode, so that the current passes through the pair of test probes 13 and an unknown resistance RX coupled therebetween, and the voltage drop across the unknown resistance RX can be detected. Measurement, and the resistance can be determined according to the following formula:

RX = voltage drop / test current

The resistance module can also include a continuity test, wherein a resistance between the pair of test probes 13 less than a critical resistance value is regarded as a short circuit and is indicated by the sound of the buzzer 16 .

The switching circuit 93 is used to switch the input signal of the analog/digital converter 98 to the ACA, DCA signal obtained by the current sensing circuit 94 through the AC rectification filter circuit 97 and the DC filter circuit 82 or the attenuation circuit 90 through the AC rectification filter circuit 97 and the AC voltage, DC voltage signal obtained by the DC filter circuit 82 or the resistance signal of the resistance detection circuit 96, and output the DC signal.

The current sensing circuit 94 includes an amplifier, a voltage divider, and the aforementioned current clamp 14, so that the current clamp 14 detects the current to generate a voltage signal coupled to the AC rectification filter circuit 97 and the switching circuit 93 to convert a voltage signal into DC signals suitable for conversion into digital measured values.

The instrument and display controller 95 processes the formatting of the digital measurement value and converts it into the format required by the display 11 according to the selected measurement mode, and controls the backlight circuit 81 to turn on and off and the buzzer 16 to sound.

The resistance detection circuit 96 detects whether the signal being measured is voltage or resistance, so as to provide a control switching circuit 93 to the instrument and display controller 95 for switching judgment and displaying the resistance value.

The analog/digital converter 98 converts the measurement value into a digital measurement value, which is sent to the instrument and display controller 95 as display judgment conditions and displayed.

The constant voltage circuit 80 provides a test voltage to the protection circuit 91 in the diode mode, and the pair of test probes 13 provides a voltage to a diode coupled therebetween, and the voltage drop across the diode can pass through the DC filter circuit 82 was measured.

The backlight circuit 81 is used to detect the current external light intensity and receive control signals from the instrument and display controller 95 to turn on or off the backlight.

And the instrument display controller 95 controls the mode to be measured according to the nature and size of the input signal, to control the state of the switching circuit 93 and the display 11, and receives the signal sent by the single control key 12, according to the length of the signal time Control the display mode or shutdown of the display 11.

In addition, the automatic hook-type meter of the present invention also includes an automatic display backlight mode and a safety warning mode, so that the display backlight will be automatically activated when operating in a dark place to facilitate users to see the readings on the display. In the automatic display backlight mode, after the ambient brightness meets the conditions for activating the display backlight, it will delay the activation of the display backlight for two seconds to reduce false operations of the backlight. And the safety warning mode provides users with the ability to measure an AC voltage, DC voltage, AC current or DC current with the test probe or current clip when using the two modes of freeze-frame instant and maximum/minimum value recording. And when the signal is different from the signal displayed on the display, it can automatically issue a warning to warn the user that such an operation is dangerous. If the above two signals are both AC voltage, DC voltage, AC current or DC current, When operating in the freeze-frame instantaneous mode, the two signals will be compared in size. If the two signals are voltage and the signal of the test probe is greater than 5.0V than the signal displayed on the display or the two signals are current and the current clamp When the signal is 5.0A greater than the signal displayed on the display, it will also automatically issue a warning. And after the safety warning mode is activated, the measured value can be designed to maintain the original locked signal or change to a new value of the signal measured later.

In addition, the measuring main body of the present invention will check the remaining power of the battery when it is turned on. 7V is 0%, 9V is 100%, and the percentage is displayed according to the actual battery power. If it is less than 7V, the battery symbol is displayed at the same time to indicate insufficient power. Check the battery level every 3 minutes after power on.

Based on the aforementioned hardware and firmware combined with the actual finished product, it can provide the following functions in measurement, making the operation of the meter more user-friendly and easy to use:

The above description is only used to reveal the practicable aspect of the present invention, and cannot be used to limit the scope of the claims of the present invention, and all those who are familiar with the ordinary skill in the art can obviously make changes and modifications, and all should be regarded as not contradictory away from the essence of the present invention.

According to the content disclosed above, the present invention can clearly achieve the expected purpose of the invention, and provide a fully automatic hook-type electric meter, which has the value of industrial application.

Claims (18)

1. A fully automatic hook-type electric meter, comprising a measuring main body, on which a display and a single control key are arranged, a test probe is inserted into the main body, and a current clip is provided on the upper end of the main body for receiving a carrier fluid; It is characterized in that the fully automatic hook meter additionally includes: An automatic judgment switching mode, which is selected by the measurement subject according to the external input conditions when starting up, and has the measurement of DC voltage mode, AC voltage mode, resistance mode, diode mode, and AC and DC current modes; and A priority detection mode, in the automatic judgment switching mode, the input of the test probe is the priority, and the input of the current clamp is secondary; Among them, when the automatic hook-type meter is turned on, it enters the initial setting and after detecting the battery power, first measures the DC voltage, then measures the AC voltage, and then performs the following series of judgment actions: a: If the measured DC voltage is greater than 999.9V and the AC voltage is also greater than 999.9V, the AC/DC voltage overflow signal will be displayed; if the AC measurement value is not greater than 999.9V, only the DC voltage overflow OL signal will be displayed; b: Assuming that the DC measurement result is between 2.1V～999.9V or between -0.5V～-999.9V, the AC voltage judgment will be performed. If the DC measurement result is greater than 999.9V, the AC voltage overflow signal will be displayed. When the AC voltage is greater than the DC voltage whose absolute value is taken, it will display the measured AC voltage and display its value, if the above judgment is otherwise, it will display the measured DC voltage and display its value; c: If the measured DC voltage is lower than 2.1V and greater than -0.5V, and the AC voltage is between 1.0V and 999.9V, the AC voltage will be displayed. If the AC voltage is greater than 999.9V, the AC voltage overflow OL signal will be displayed. If The AC voltage is not greater than 0.9V, and if the absolute value of the DC voltage measurement result is less than or equal to 1.1V, it will automatically switch to the resistance measurement mode, and if the AC voltage is greater than 0.2V, it will automatically switch to the diode measurement mode : d: Enter the resistance measurement mode, and if it is judged that the resistance is less than 10000 ohms, the measured resistance value will be displayed, and the resistance will be measured continuously, and the AC voltage will be measured once after every two resistance measurements. If the AC voltage measurement result is greater than or equal to 1.0V, the AC voltage will be displayed, otherwise, the resistance will be continuously measured, and if it is greater than 9999 ohms, it will jump to the diode measurement mode; e: Enter the measurement diode mode, judge that the voltage value at both ends of the diode is between 0.3V and 0.9V, then display the measured voltage value, and jump to the current measurement mode if it is not within the range; f: Enter the current measurement mode, measure the DC current, and then measure the AC current. If the measurement result of the DC current is greater than 999.9A and the AC current is also greater than 999.9A, the AC and DC current overflow signal will be displayed. If the AC measurement value is not greater than At 999.9A, only the DC current overflow signal is displayed; g: Assuming that the absolute value of the DC current measurement result is between 0.6A and 999.9A, the AC current will be judged. If it is greater than 999.9A, the AC current overflow signal will be displayed. If it is not the above situation, when the AC current is greater than the DC current of the absolute value , it shows that the measured AC current is displayed and its value is displayed; otherwise, it is displayed that the measured one is DC current and its value is displayed; and h: If the measured DC current is lower than 0.6A and greater than -0.6A, and the AC current is between 0.6A and 999.9A, it will display the AC current. If the AC current is greater than 999.9A, it will display the AC current overflow OL signal. When the current is not greater than 0.6A, the status of the resistance file overflow is displayed. 2. The fully automatic hook-type electric meter as claimed in claim 1, characterized in that, when there is a voltage input at both ends of the test probe in DC voltage mode, AC voltage mode, diode mode or resistance mode and a signal can be measured, it will display For the relative value of voltage, diode or resistance, the current value measured by the current clamp will be displayed only when the test probe is open and no signal is input. If the current clamp cannot measure the current, it will display the resistance file overflow (OL )state. 3. The fully automatic hook-type electric meter as claimed in claim 2, wherein the resistance mode can also include a continuity test, wherein the resistance between the pair of test probes to a resistance less than a critical resistance value is regarded as a short circuit, And be indicated through the display and a buzzer. 4. The fully automatic hook-type electric meter as claimed in claim 1, characterized in that, the single control key of the measuring main body can start and shut down the power supply meter, and after turning on the power meter, start a certain frame instantaneous mode, a measurement maximum value/ Minimum value recording mode, a DC current residual magnetism zeroing mode, a canceling automatic freeze instantaneous mode and a canceling automatic power-off mode; among them, it is used to start the meter in the power-off state, and it will power on if pressed for more than 2 seconds when the power is off And cancel the automatic shutdown mode, if it is less than 2 seconds, it will only do the power-on action; if it is turned on and has the automatic shutdown mode, if it is pressed for more than 3 seconds, it will be shut down, and if it is more than 1 second, it will perform the DC current residual magnetism reset action. 1 second is to start the freeze-frame instantaneous mode, press it again to cancel the freeze-frame instantaneous mode; in the state of turning on and canceling the automatic shutdown mode, press for more than 3 seconds to shut down, and more than 1 second to perform DC current residual magnetism return Zero action, when it is less than 1 second, it starts to measure the maximum value/minimum value recording mode; in the power-on state, if the automatic freeze-frame instantaneous mode is activated, press once to switch the automatic freeze-frame instantaneous mode into the freeze-frame instantaneous mode, press more than 3 If it is over 1 second, it will perform the DC current remanence return to zero action; in the power-on state, if the maximum value/minimum value recording mode is activated, press it to display the recorded maximum value. Press it again to display the recorded minimum value, press it again to display the currently measured signal value, press it again to display the recorded maximum value, and switch in this way, when pressed for more than 3 seconds, it will shut down , more than 1 second is to do DC current remanence zero action. 5. The fully automatic hook-type electric meter as claimed in claim 4, characterized in that, when the measuring body freezes the instantaneous mode to start, there will be a beep and the display will display the "HOLD" symbol. At this time, the screen does not change, and the freeze-frame instantaneous mode is turned off It rang again. 6. The fully automatic hook-type electric meter as claimed in claim 4, characterized in that, in the state of starting the automatic shutdown mode when starting up, when measuring the current, when a value greater than or equal to a certain set current value is measured , which is called the instant of automatic freeze frame. It will automatically start when the minimum current measurement value is stable. When starting, it will beep three times continuously and the display will display two symbols of "AUTO" and "HOLD". At this time, the screen does not change but continues to monitor Test the signal of the probe and the current clip, press the button to automatically freeze the instantaneous mode and it will switch to the freeze instantaneous mode and there will be a beep. At this time, the screen remains unchanged. Freeze the stable current of the instantaneous minimum current measurement value and the difference between the current value and the value on the display exceeds 0.2A, restart the automatic freeze instantaneous mode to keep displaying new measurement results; after the automatic freeze instantaneous mode is started, if the current When the current measured by the clip measurement is less than the minimum instantaneous current measurement value of the automatic freeze frame or is an unsteady current, the automatic freeze frame instantaneous mode will be automatically canceled after 5 seconds; after the automatic freeze frame instantaneous mode is activated, it will still measure whether the probe has a signal , if there is, immediately leave the automatic freeze-frame instantaneous mode and switch to the appropriate mode for measurement and display. 7. The fully automatic hook-type electric meter as claimed in claim 4, characterized in that, when the automatic power-off mode is canceled and the AC and DC voltages or AC and DC currents are measured, if the button is pressed for less than 1 second, it will Start the measurement maximum value/minimum value recording mode, there will be a beep and the display will display the "RECORD" symbol when starting up, and then the meter will continue to record the measured maximum value and minimum value after entering the measurement maximum value/minimum value recording mode. The minimum value, the current measurement value is displayed on the display at the same time; after pressing the control button, the recorded maximum value and the "MAX" symbol will be displayed and a beep will be heard, and pressing it again will be displayed and the recorded minimum value and "MIN" symbol will be beeped , press it again, it will display the current measurement result and the "RECORD" symbol and make a beep, and switch in this way; if pressed for more than 1 second, it will execute the DC current remanence zero mode, and leave the measurement maximum/minimum value record mode, it will be turned off when it exceeds 3 seconds. 8. The fully automatic hook-type ammeter as claimed in claim 4, which further includes an automatic display backlight mode, which will automatically activate the display backlight to facilitate the user to see the reading on the display when operating in a dark place; the automatic display In backlight mode, after the ambient brightness meets the conditions for starting the display backlight, it will delay the start of the display backlight for 2 seconds to reduce backlight misoperation. 9. The fully automatic hook-type electric meter as claimed in claim 4, which further includes a safety warning mode, which provides users with the ability to test probes when using the two modes of freezing instant and measuring maximum/minimum value recording. Or when the current clip measures an AC voltage, DC voltage, AC current or DC current, and the signal is different from the signal displayed on the display, it can automatically issue a warning to warn the user that such an operation is dangerous. When the above two signals are AC voltage, DC voltage, AC current or DC current, when the operation is in the freeze-frame instantaneous mode, the two signals will be compared in size. If the two signals are voltage and the test probe When the signal is greater than 5.0V than the signal displayed on the display or when the two signals are current and the signal of the current clamp is 5.0A greater than the signal displayed on the display, an automatic warning will also be issued. 10 . The fully automatic hook-type electricity meter as claimed in claim 9 , wherein after the safety warning mode is activated, the measured value will be changed to a new value of the signal measured later. 11 . 11. The fully automatic hook-type electric meter as claimed in claim 4, characterized in that, in the automatic power-off mode, when the user still does not operate 20 minutes after the last operation, the power will be automatically turned off. 12. The fully automatic hook-type electric meter according to claim 4, characterized in that, when the measuring body presses the control key for more than 1 second, the DC current residual magnetism reset mode can be executed, and the current can be clamped to measure the DC current The remanence effect generated during the operation is eliminated, and the symbols "DC", "0.0", "A", and "ZERO" are displayed for 2 seconds to indicate the execution of this action. 13. The fully automatic hook-type electric meter as claimed in claim 1, its internal composition circuit comprises: an attenuation circuit and a protection circuit coupled to the test probe; A constant current circuit that provides a test current to the protection circuit in resistance mode; A constant voltage circuit that provides a test voltage to the protection circuit in diode mode; A switch circuit, used to switch the source of the input signal is the AC current obtained by the current sensing circuit through an AC rectification filter circuit and a DC filter circuit, the DC current signal, and the attenuation circuit obtained by the AC rectification filter circuit and the DC filter circuit The AC voltage, DC voltage signal or signal of the resistance detection circuit, and output the DC signal; An instrument and display controller, according to the selected measurement mode, convert the format of the digital measurement value into the format required by the display, and control the backlight circuit on and off and the sound of the buzzer; A resistance detection circuit, which detects that the type of the signal being measured is voltage or resistance, so as to provide a control switching circuit to the instrument and display controller for switching judgment and displaying the resistance value; A current sensing circuit, including an amplifier, a voltage divider, and an aforementioned current clamp, the current clamp detects the current to generate an AC signal and a DC signal, and the AC signal is coupled and sent to the AC rectification and filtering circuit to convert an AC signal into an appropriate To convert the DC signal into a digital measurement value, the DC signal is coupled and sent to the DC filter circuit; An analog/digital converter, which converts the measurement value into a digital measurement value, sends it to the instrument and the display controller, and displays it as the judgment condition of the display; and A backlight circuit detects the current external light intensity and receives control signals from the instrument and display controller to turn on or off the backlight. 14. The fully automatic hook-type electric meter as claimed in claim 13, characterized in that, the attenuation circuit provides a regulated input voltage to the aforementioned switching circuit and the AC rectification and filtering circuit, the switching circuit is controlled by the instrument and the display controller, Output the corresponding voltage, current, diode or resistance signal to the analog/digital converter according to the current measured mode. 15. The fully automatic hook-type electric meter as claimed in claim 13, characterized in that, the instrument and the display controller determine the measurement mode based on the nature and size of the input signal to control the state of the switching circuit and the display, and receive the input signal from The signal sent by a single control key changes the state of the display according to the length of the signal time. 16. The fully automatic hook-type electricity meter as claimed in claim 13, wherein the backlight circuit can activate the display backlight when the meter is operated in a dark place and sends a signal to the instrument and the display controller. 17. The fully automatic hook-type electric meter as claimed in claim 1, characterized in that, when the measuring body is turned on, it will check the remaining power of the battery, with 7V as 0% and 9V as 100%, and it will be determined according to the actual power of the battery. Percentage display, if it is less than 7V, the battery symbol will be displayed at the same time to indicate insufficient power. Check the battery level every 3 minutes after power on. 18. The fully automatic hook-type electric meter as claimed in claim 1, characterized in that, the measuring body is a long shell, the bottom of which is narrower than the top and bottom, making it easy to hold, and there is another buzzer inside it .

Images