CN212258913U

CN212258913U - Differential amplifier module circuit in short-circuit fault warning device of ammeter

Info

Publication number: CN212258913U
Application number: CN202020921463.2U
Authority: CN
Inventors: 刘长辉
Original assignee: Guangzhou Huaming Electric Power Technology Co ltd
Current assignee: Guangzhou Huaming Electric Power Technology Co ltd
Priority date: 2020-05-27
Filing date: 2020-05-27
Publication date: 2020-12-29
Anticipated expiration: 2030-05-27

Abstract

The utility model discloses a differential amplifier module circuit among ammeter short circuit fault warning device, including differential amplification processing unit, single-ended signal isolation output unit and output single-ended signal zero setting circuit, differential amplification processing unit includes the third chip, mainly comprises operational amplifier, and the third chip is equipped with second pin and third pin and constitutes the input differential signal foot, is equipped with the sixth pin and constitutes the output signal foot, is equipped with first pin and eighth pin and constitutes the amplified signal pin, is equipped with the fifth pin and constitutes the input reference voltage pin, makes the output of sixth pin more accurate; the single-ended signal isolation output unit comprises a fifth second chip which is a voltage follower, and the output end of the voltage follower is connected with the negative electrode input end to form an isolated signal output end. The utility model discloses carry out the accuracy to real-time supervision's signal and enlarge, when the short circuit appears, for the disconnection main line to the warning provides reliable control signal, the safety of effectual protection main line.

Description

Differential amplifier module circuit in short-circuit fault warning device of ammeter

Technical Field

The utility model relates to an ammeter short circuit trouble warning device's technical field, concretely relates to differential amplifier module circuit's among ammeter short circuit trouble warning device technique.

Background

With the rapid development of the social and economic level, the continuously rising power demand promotes the development of the power industry and promotes the comprehensive upgrade of the power grid system. In order to improve the service quality of the power industry and bring better electricity consumption experience for residents, the construction of the smart power grid is also carried out rapidly. At present, in the construction of a smart power grid, a low-voltage centralized meter reading system is more and more mature, and is applied to a plurality of places, so that intelligent remote meter reading is realized, and the meter reading efficiency and the electronization settlement rate are effectively improved. However, the low-voltage meter reading system still has some problems, and RS485 short circuit faults sometimes occur in the meter reading system. When the short circuit fault occurs at the port of the RS485, the communication paralysis of the RS485 area can be caused, no reliable tool can be used for quickly positioning a fault point at present, the fault detection can be carried out only by a binary breakpoint method, the troubleshooting and the processing are required to be carried out for one day or even longer, and the electronic settlement rate and the online rate are seriously influenced. And the RS485 is the name of a cable.

Therefore, the electric meter short-circuit fault warning device is emphasized by people, when a short-circuit fault occurs on a line connected with an electric meter, a monitored signal is weak generally, and the control is needed, so that the electric meter short-circuit fault warning device is difficult to process and cannot process well, and functions of the electric meter short-circuit fault warning device can be influenced, such as disconnection of a main line, fault indication on a short-circuit position and the like.

SUMMERY OF THE UTILITY MODEL

In order to overcome the defects of the prior art, the utility model aims to provide a differential amplifier module circuit among ammeter short circuit fault warning device carries out the accuracy to the signal of connecting the branch circuit condition real-time supervision of household ammeter and enlargies, when the short circuit appears, for the disconnection main line to the safety that the warning provides reliable control signal, effectual protection main line.

To achieve the purpose, the utility model adopts the following technical proposal:

the utility model provides a differential amplifier module circuit among ammeter short circuit fault warning device which characterized in that: the differential amplifier module circuit in the electric meter short-circuit fault warning device comprises a differential amplification processing unit, a single-ended signal isolation output unit and an output single-ended signal zero setting circuit, wherein the output single-ended signal zero setting circuit is in circuit connection with the differential amplification processing unit and is used for outputting direct current signals for zero setting, the differential amplification processing unit comprises a third chip, the third chip mainly comprises an operational amplifier, the third chip is provided with a second pin and a third pin to form an input differential signal pin, a sixth pin to form an output signal pin, a first pin and an eighth pin to form an amplification signal pin, a seventh resistor is connected between the first pin and the eighth pin and used for amplifying output voltage, the seventh resistor is used for adjusting amplification factor, and a fifth pin to form an input reference voltage pin, so that the sixth pin is more accurately output; the single-ended signal isolation output unit comprises a fifth second chip, the fifth second chip is a voltage follower and is used for enhancing the output voltage driving capability of a sixth pin of the third chip and reducing interference, the sixth pin of the third chip is connected with a first and a second resistors and is a single-ended signal isolation output resistor, the first and the second resistors are connected with a positive electrode input end of the fifth second chip, and an output end of the fifth second chip is connected with a negative electrode input end of the fifth second chip to form an isolated signal output end.

The output single-ended signal zero setting circuit comprises a fifth chip, wherein the fifth chip is a voltage follower and is used for connecting a fifth pin of the third chip, the positive input end of the fifth chip is connected with an eighth resistor and a ninth resistor, one end of the eighth resistor is connected with a positive voltage, the other end of the eighth resistor is connected with one end of the ninth resistor and is connected with the positive input end of the fifth chip together, one end of the ninth resistor is connected with a negative voltage, a series node of the eighth resistor and the ninth resistor is 0V to form the zero setting device, and the voltage of the fifth pin of the third chip is 0V.

The resistance values of the eighth resistor and the ninth resistor are both 1K omega, the voltage connected to one end of the ninth resistor is-5V, and the voltage connected to one end of the eighth resistor is + 5V; the seventh resistance value is 49.9K Ω with an accuracy of ± 1%.

The utility model discloses following beneficial effect has:

the utility model discloses because differential amplifier module circuit includes difference amplification processing unit, single-ended signal isolation output unit and output single-ended signal zero setting circuit, the third chip in the difference amplification processing unit is equipped with seventh resistance and is used for the magnification to adjust, and the third chip is equipped with the fifth pin and constitutes input reference voltage pin, makes the output of sixth pin more accurate; the differential amplification processing unit also carries out single-ended signal isolation on the signal through the single-ended signal isolation output unit, and finally obtains an isolated signal output for a starting signal of a subsequent triode; and the design of the output single-ended signal zero setting circuit enables the voltage of a fifth pin of the third chip to be 0V. It is thus clear, through the technical scheme of the utility model, realized carrying out the accuracy to the signal of the branch circuit condition real-time supervision who connects the household ammeter and enlargies, when the short circuit appears, for the disconnection main line to the warning provides reliable control signal, the safety of effectual protection main line.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required to be used in the embodiments of the present invention will be briefly described below. It is obvious that the drawings described below are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be obtained from these drawings without inventive effort.

Fig. 1 is a schematic block diagram of a circuit of a differential amplifier module circuit in the short-circuit fault warning device of the utility model;

fig. 2 is a schematic circuit diagram of a differential amplifier module circuit in the short-circuit fault warning device of the utility model;

fig. 3 is the utility model is a circuit schematic diagram for ammeter RS485 branch line short circuit fault warning device.

Detailed Description

The technical solution of the present invention is further explained by the following embodiments with reference to the accompanying drawings.

Wherein the showings are for the purpose of illustration only and are shown by way of illustration only and not in actual form, and are not to be construed as limiting the present patent; for a better understanding of the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.

The same or similar reference numerals in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "inner", "outer", etc. are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, it is only for convenience of description and simplification of description, but it is not indicated or implied that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and therefore, the terms describing the positional relationship in the drawings are used only for illustrative purposes and are not to be construed as limiting the present patent, and the specific meaning of the terms will be understood by those skilled in the art according to the specific circumstances.

The differential amplifier module circuit in the short-circuit fault warning device of the utility model comprises a differential amplification processing unit, a single-ended signal isolation output unit and an output single-ended signal zero setting circuit, wherein the output single-ended signal zero setting circuit is in circuit connection with the differential amplification processing unit and is used for outputting direct current signal zero setting, the differential amplification processing unit comprises a third chip, the third chip mainly comprises an operational amplifier, the third chip is provided with a second pin and a third pin to form an input differential signal pin, a sixth pin to form an output signal pin, a first pin and an eighth pin to form an amplification signal pin, a seventh resistor is connected between the first pin and the eighth pin and used for amplifying output voltage, the seventh resistor is used for adjusting amplification factor, and a fifth pin to form an input reference voltage pin, so that the sixth pin is more accurately output; the single-ended signal isolation output unit comprises a fifth second chip, the fifth second chip is a voltage follower and is used for enhancing the output voltage driving capability of a sixth pin of the third chip and reducing interference, the sixth pin of the third chip is connected with a first and a second resistors and is a single-ended signal isolation output resistor, the first and the second resistors are connected with a positive electrode input end of the fifth second chip, and an output end of the fifth second chip is connected with a negative electrode input end of the fifth second chip to form an isolated signal output end. The output single-ended signal zero setting circuit comprises a fifth chip, wherein the fifth chip is a voltage follower and is used for connecting a fifth pin of a third chip, the positive electrode input end of the fifth chip is connected with an eighth resistor and a ninth resistor, one end of the eighth resistor is connected with a positive voltage, the other end of the eighth resistor is connected with one end of the ninth resistor and is connected with the positive electrode input end of the fifth chip together, one end of the ninth resistor is connected with a negative voltage, a series node of the eighth resistor and the ninth resistor is 0V to form the zero setting device, and the voltage of the fifth pin of the third chip is 0V. The resistance values of the eighth resistor and the ninth resistor are both 1K omega, the voltage connected with one end of the ninth resistor is-5V, and the voltage connected with one end of the eighth resistor is + 5V; the seventh resistance value is 49.9K Ω with an accuracy of ± 1%.

As shown in the schematic circuit diagrams of fig. 2 and 3: +5V represents supply + 5V; -5V represents power-5V; GND represents power ground.

The pin numbers in fig. 2 and 3 are described according to the conventional language in the industry, such as pin 1 being the first pin and pin 2 being the second pin, for space saving, not to be listed; the chip numbers are also described in accordance with the languages customary in the industry, such as U3, i.e., the third chip, and U5.1, i.e., the fifth chip. The user meter interface in the figure is the user meter interface. The user meter is short for the user electric meter.

Fig. 1 corresponds to fig. 2, and the components of fig. 3 illustrate:

differential input: the user electric meters a and B are respectively input to U3, pin 2 of the third chip, i.e., the second pin, and pin 3, i.e., the third pin.

Difference amplification processing: u3, the third chip, is mainly composed of an operational amplifier.

Adjusting the magnification: r7, a seventh resistor, is connected in series at pin 1 and pin 2 of U3.

Single-ended signal output: pin 6 of U3, the sixth pin, outputs a single-ended signal to the series R12, the first diode.

Output single-ended signal zeroing: the series node of the R8, i.e. the eighth resistor, and the R9, i.e. the ninth resistor, is connected to the operational amplifier U5.1, i.e. the pin 5 of the fifth chip, and the pin 6 and the pin 7 of the U5.1 are connected to form a voltage follower and to the pin 5 of the U3.

Single-ended signal isolation output: u5.2 is the fifth chip, and operational amplifier constitutes the voltage follower, and pin 3 connects single-ended signal output line, and pin 1 and pin 2 connect and single-ended signal isolation output.

Basic principle in fig. 1: the voltage across the differential input is in millivolts, so it needs to be amplified by tens of times to become in volts and become a single-ended signal output. The differential input is subjected to differential amplification processing to become single-ended signal output, and then the signal is isolated and output.

Components illustrated in fig. 2:

u3 third chip: the instrument operational amplifier is used for amplifying input differential signals; wherein pin 2, i.e., the second pin, and pin 3, i.e., the third pin, are input differential signal pins, and pin 6, i.e., the sixth pin, is an output signal pin; the pin 1, namely the first pin, and the pin 8, namely the eighth pin, are amplification pins, and the series resistor can amplify output voltage; the pin 5, i.e., the fifth pin, is the input reference voltage pin, so that the pin 6, i.e., the sixth pin, outputs more accurately.

R7 is seventh resistance: the value is 49.9 K.OMEGA./1%, and is connected in series with pin 1 and pin 3 of U3, so that U3 amplifies the output voltage.

R12 is the first diode: a value of 1K omega reduces the signal current output at pin 6 of U3 and reduces interference.

U5 is referred to as the fifth chip: a dual operational amplifier (U5.1, i.e., a fifth first chip, and U5.2, i.e., a fifth second chip); u5.2, namely the fifth chip, forms a voltage follower, the driving capability of the output voltage of the pin 6 of U3 is enhanced, and the interference is reduced; u5.1, the fifth chip, constitutes pin 5 of the voltage follower connection U3.

R8 eighth resistor, R9 ninth resistor: the value is 1K omega, the serial node of R8 and R9 is 0V, and the pin 5 of U5.1 is connected to form a zero regulator, so that the voltage of the pin 5 of U3 is 0V.

Fig. 3 is the utility model is a circuit schematic diagram for ammeter RS485 branch line short circuit fault warning device. Ammeter RS485 branch line short circuit fault warning device is except including differential amplifier module circuit also for short differential amplifier module still including setting up two way relay drive module, voltage comparator module, warning light module and the power module in the shell, power module truns commercial power 220V into 5V constant voltage power supply.

In fig. 3, the two relay driving modules include a triode, a relay coil and a relay two-way switch, the relay coil and the relay two-way switch form two relays, the triode is a PNP triode and is used for controlling the conduction of a 5V power supply so as to control the power switch of the relay two-way switch, the relay coil is used for controlling the opening and closing of the relay two-way switch, the two relays are provided with a first pin and an eighth pin to form a relay coil pin, an emitter of the triode is electrically connected with an eighth pin of the two relays, the first pin is connected with a power ground, the two relays are further provided with a second pin, a third pin, a fourth pin, a fifth pin, a sixth pin and a seventh pin, the fourth pin, the fifth pin and the sixth pin form a first relay, and the second pin, the third pin and the fourth pin form a second relay, the fourth pin and the fifth pin of the two relays are disconnected and are not used, the sixth pin and the seventh pin are closed by default, the second pin and the third pin are closed by default, the second pin and the sixth pin are used for connecting an RS485 trunk line interface, the third pin and the seventh pin are used for connecting an RS485 branch line interface, the output end of the differential amplifier module is connected with the input end of the voltage comparator module, the output end of the voltage comparator module is divided into two paths, one path is connected with the base electrode of the triode, the other path is connected with the warning lamp module, the collector of the triode is connected with a 5V power supply, the input differential signal end of the differential amplifier module is connected with an RS485 branch line interface, the differential amplifier module and the voltage comparator module are used for monitoring the RS485 branch line condition of the electric meter in real time, when a short circuit occurs, the two relays are driven to disconnect the RS485 trunk line, and the LED warning lamp is turned on to warn.

In fig. 3, the voltage comparator module includes a sixth chip, and a first fourth resistor and a first third resistor connected in series, the sixth chip is a voltage comparator, the sixth chip has a third pin as a positive-phase input end, a second pin as a negative-phase input end, and a first pin as an output end, a series node of the first fourth resistor and the first third resistor is connected to the second pin of the sixth chip, a node voltage of a series node of the first fourth resistor and the first third resistor is 1V, an input differential signal pin of the third chip of the differential amplification processing unit is connected to an RS485 branch line interface, an output signal pin of the third chip of the differential amplification processing unit is connected to a positive-phase input end of a fifth second chip of the single-ended signal isolation output unit through a first and a second resistor, an isolated signal output end of the fifth chip of the single-ended signal isolation output unit is connected to the positive-phase input end of the sixth chip of the voltage comparator module, the output end of the sixth chip is in circuit connection with a PNP triode, an emitting electrode of the PNP triode is connected with a warning lamp module, the differential amplification processing unit detects two ends of a user electric meter, when no short circuit exists at the two ends of the user electric meter, voltage is generated, the differential amplification processing unit amplifies the voltage at the two ends of the user electric meter to the maximum 3.7V and provides the voltage to the voltage comparator module, when the voltage comparator module detects that the input voltage is larger than 1V of a threshold value, a high level is output, the PNP triode is not driven, and the warning lamp module is not driven; when the two ends of the user electric meter are short-circuited, the differential amplification processing unit detects the short circuit of the two ends of the user electric meter, the two ends of the differential amplification processing unit are also short-circuited, the differential amplification processing unit directly outputs a low level to the voltage comparator module at the moment, the voltage comparator module outputs a high level when an input voltage threshold value is larger than 1V, and outputs a low level when the input voltage threshold value is smaller than 1V, the voltage comparator module outputs a low level, and the PNP triode drives the warning lamp module to enable the LED warning lamp to light. The third chip is provided with a second pin and a third pin to form the input differential signal pin, a sixth pin to form the output signal pin, a first pin and an eighth pin to form an amplification signal pin, a seventh resistor is connected in series between the first pin and the eighth pin to amplify output voltage, the seventh resistor is used for adjusting amplification factor, and a fifth pin to form an input reference voltage pin, so that the output of the sixth pin is more accurate.

As shown in fig. 3, when the two ends of the user electric meter AB are short-circuited and the differential amplifier module detects the short circuit of the two ends of the user electric meter AB, the two ends of the differential amplifier are also short-circuited, at this time, the differential amplifier directly outputs a low level (-1V-0.5V) to the voltage comparator module, the voltage comparator module outputs a high level when setting an input voltage threshold value greater than 1V and outputs a low level when setting an input voltage threshold value less than 1V, so that the voltage comparator outputs a low level, the voltage comparator outputs a low level and directly enables the PNP triode to drive the two relay contacts, wherein the two relays are closed by default and are opened, thereby achieving the purpose of protecting the trunk line RS485 and simultaneously driving the warning lamp to flash by the PNP triode. The power module gets electricity from the alternating current 220V end of the ammeter and converts the electricity into a direct current 5V power supply, namely the 220V is converted into 5V voltage stabilization as shown in the figure, and the voltage stabilization is used by each module power supply. The figure shows the abbreviation used for the user meter AB, i.e. the user meter AB typeface.

In fig. 3, R14 is a first four-resistor, R13 is a first three-resistor: the node voltage of the series connection of R14 and R13 is 1V with the values of 39K omega and 10K omega.

U6 is referred to as the sixth chip: the voltage comparator only uses one voltage comparator U6.1, namely a sixth chip, a pin 3 of the U6.1, namely a third pin of the sixth chip, is a positive phase input end, a pin 2, namely a second pin of the sixth chip, is an inverted phase input end, and the output voltages of the

pins

1 and 2 of the U5.2 are compared; pin 1 of U6.1 is the output terminal; the node voltage of the series connection of R14 and R13 is connected with the inverting input/output end of the pin 2 of U6.1, so that the inverting input end of the pin 2 of U6.1 is 1V; when the voltage of the pin 3 of the U6.1 is greater than the voltage of the pin 2 of the U6.1, the pin 1 of the U6.1 outputs a high level (not less than 1.5V and not more than 3.9V); when the voltage of pin 3 of U6.1 is less than the voltage of pin 2 of U6.1, pin 1 of U6.1 outputs a low level (not more than 3.9V).

R16 is the first sixth resistor; with a value of 4.7K omega, a voltage of 5V is pulled up, keeping transistor Q2 in an off state.

R15 is the first five resistances: a value of 3.6K omega, reduces the effect of the current.

Q2 is PNP triode with model number of 2N3904, and is manufactured by Anson; the function is to control the RELAY2, i.e. the power switch of the two-way RELAY.

RELAY 2: two-way relay, model HFD4/5-S, factory building door macro-switch equipment; pin 1 and pin 8 are relay coils; the pin 4, the pin 5 and the pin 6 are one path of relay, and the pin 2, the pin 3 and the pin 4 are a second path of relay; pins 4 and 5 of the principle diagram are not used; default pins 6 and 7 are closed, and pins 2 and 3 are closed. According to the working principle, when the Q2 triode is switched on, the pin 1 and the pin 8 of the RELAY2 are powered on, then the pin 6 and the pin 7 are disconnected, and the pin 2 and the pin 3 are disconnected, so that the disconnection between the main line and the user electric meter is achieved.

The LED indicates a red light, and the transistor Q2 lights when turned on.

R17 first seventh resistance: the value is 1K Ω, reducing the current.

It should be noted that the above embodiments are only preferred embodiments of the present invention and the technical principles applied, and any changes or substitutions which can be easily conceived by those skilled in the art within the technical scope of the present invention are also included in the protection scope of the present invention.

Claims

1. The utility model provides a differential amplifier module circuit among ammeter short circuit fault warning device which characterized in that: the differential amplifier module circuit in the electric meter short-circuit fault warning device comprises a differential amplification processing unit, a single-ended signal isolation output unit and an output single-ended signal zero setting circuit, wherein the output single-ended signal zero setting circuit is in circuit connection with the differential amplification processing unit and is used for outputting direct current signals for zero setting, the differential amplification processing unit comprises a third chip, the third chip mainly comprises an operational amplifier, the third chip is provided with a second pin and a third pin to form an input differential signal pin, a sixth pin to form an output signal pin, a first pin and an eighth pin to form an amplification signal pin, a seventh resistor is connected between the first pin and the eighth pin and used for amplifying output voltage, the seventh resistor is used for adjusting amplification factor, and a fifth pin to form an input reference voltage pin, so that the sixth pin is more accurately output; the single-ended signal isolation output unit comprises a fifth second chip, the fifth second chip is a voltage follower and is used for enhancing the output voltage driving capability of a sixth pin of the third chip and reducing interference, the sixth pin of the third chip is connected with a first and a second resistors and is a single-ended signal isolation output resistor, the first and the second resistors are connected with a positive electrode input end of the fifth second chip, and an output end of the fifth second chip is connected with a negative electrode input end of the fifth second chip to form an isolated signal output end.

2. The differential amplifier module circuit in the electric meter short-circuit fault warning device according to claim 1, characterized in that: the output single-ended signal zero setting circuit comprises a fifth chip, wherein the fifth chip is a voltage follower and is used for connecting a fifth pin of the third chip, the positive input end of the fifth chip is connected with an eighth resistor and a ninth resistor, one end of the eighth resistor is connected with a positive voltage, the other end of the eighth resistor is connected with one end of the ninth resistor and is connected with the positive input end of the fifth chip together, one end of the ninth resistor is connected with a negative voltage, a series node of the eighth resistor and the ninth resistor is 0V to form the zero setting device, and the voltage of the fifth pin of the third chip is 0V.

3. The differential amplifier module circuit in the electric meter short-circuit fault warning device according to claim 2, characterized in that: the resistance values of the eighth resistor and the ninth resistor are both 1K omega, the voltage connected to one end of the ninth resistor is-5V, and the voltage connected to one end of the eighth resistor is + 5V; the seventh resistance value is 49.9K Ω with an accuracy of ± 1%.