CN218976328U - Remote communication water meter based on NB-iot communication - Google Patents

Abstract

The application discloses remote communication water gauge based on NB-iot communication, it includes water gauge body, power module and thing networking communication module, power module install in the water gauge body, thing networking communication module install in the water gauge body, power module be used for to thing networking communication module with the water gauge body power supply, remote communication water gauge still includes power protection module, power protection module includes voltage detection unit, signal comparison unit, switch unit and suggestion unit. The utility model has the advantages of when power module appears the short circuit, the power module stop power supply is controlled to the switch unit output second switching signal, and the suggestion unit output audible and visual suggestion signal is in order to point out the staff this moment voltage detection signal in order to detect the condition that power module exists the short circuit, need in time maintain or change power module, be convenient for carry out the effect of protection to the remote communication water gauge when the remote communication water gauge takes place the short circuit.

Description

Remote communication water meter based on NB-iot communication

Technical Field

The application relates to the technical field of intelligent water meters, in particular to a remote communication water meter based on NB-iot communication.

Background

The narrowband Internet of things (namely NB-iot) is an important branch of the Internet of everything, and NB-iot has the advantages of low power consumption, wide coverage, low cost and the like, and is widely applied to the field of remote meter reading.

The traditional remote communication water meter based on NB-iot communication, wherein the NB communication module mainly comprises a power supply module, a main control module and an interaction module, the main control module is used for receiving and processing data, and the interaction module is used for interacting the data of the water meter with the data of the main control module; the power supply module is used for supplying power to the main control module, and the radio frequency end of the main control module is used for outputting data to an external cloud platform; people can directly extract the water meter data of the cloud platform, and the efficiency of people for reading the water meter data is improved.

However, most of the existing outdoor water meters lack protection measures, and the water meters are easy to be short-circuited in long-time rain and insolation, so that the water meters are damaged, and therefore, a certain improvement space exists

Disclosure of Invention

In order to protect the remote communication water meter when the remote communication water meter is short-circuited, the application provides the remote communication water meter based on NB-iot communication.

The application provides a remote communication water gauge based on NB-iot communication adopts following technical scheme:

a telecommunications water meter based on NB-iot communications, comprising: the water meter body, power module and thing networking communication module, power module install in the water meter body, thing networking communication module install in the water meter body, power module be used for to thing networking communication module with the water meter body power supply, its characterized in that, power module includes: the remote communication water meter further comprises a power protection module, wherein the power protection module comprises:

the voltage detection unit is used for detecting the voltage of a main power supply loop of the power supply module and sending out a voltage detection signal;

a signal comparison unit coupled to the voltage detection unit to receive the voltage detection signal and provided with a threshold voltage signal VREF, the signal comparison unit comparing the voltage detection signal with the threshold voltage signal VREF and outputting a comparison signal, the comparison signal including a first type level signal and a second type level signal;

the switch unit is coupled to the signal comparison unit and is sequentially connected in series in the main power supply loop and the standby power supply loop of the power supply module, so as to output a switch signal after receiving the comparison signal, wherein the switch signal comprises: the switching unit outputs a first switching signal when receiving the first level signal, the switching unit outputs a second switching signal when receiving the second level signal, a main power supply loop of the power supply module is conducted when receiving the first switching signal, and a standby power supply loop of the power supply module is cut off when receiving the first switching signal; the main power supply loop of the power supply module is cut off when the second switch signal is received, and the standby power supply loop of the power supply module is conducted when the second switch signal is received;

the prompting unit is coupled with the switch unit and sends out an acousto-optic prompting signal when receiving the second switch signal.

By adopting the technical scheme, the power supply module is provided with a main power supply loop and a standby power supply loop for supplying power; the voltage detection unit is used for detecting the power supply voltage of the power supply module in real time and outputting a voltage detection signal, when the main power supply loop of the power supply module normally works and no short circuit occurs, the voltage detection signal output by the voltage detection module is larger than a threshold voltage signal VREF, the signal comparison unit outputs a first level signal, the switching unit receives the first level signal and then outputs a first switching signal to control the main power supply loop of the power supply module to be conducted, the standby power supply loop is cut off, and the power supply module normally operates to supply power to the Internet of things communication module and the water meter body; when the main power supply loop of the power supply module is short-circuited, the voltage of the power supply module is zero, the voltage detection signal output by the voltage detection module is smaller than the threshold voltage signal VREF, the signal comparison unit outputs a second level signal, the switch unit outputs a second switch signal after receiving the second level signal to control the main power supply loop of the power supply module to cut off, the standby power supply loop is conducted, namely the main power supply loop stops supplying power, and the standby power supply loop is started to supply power; the prompting unit outputs an acousto-optic prompting signal to prompt a worker that the voltage of the main power supply loop of the power supply module is zero by the voltage detection signal, and the power supply module needs to be maintained or replaced in time, so that the power supply module is effectively prevented from running continuously under the condition of short circuit so as to damage the water meter or overlarge current under the condition of short circuit, the temperature is raised to the condition of fire, and the remote communication water meter is convenient to protect when the remote communication water meter is short-circuited.

Preferably, the power supply module comprises a main power supply and a standby power supply, wherein the main power supply is coupled to the water meter body, the main power supply and the water meter body are positioned in an independent power supply loop, the standby power supply is coupled to the water meter body, the standby power supply and the water meter body are positioned in an independent power supply loop, the power supply loop of the main power supply is conducted when the first switch signal is received, and the power supply loop of the main power supply is cut off when the second switch signal is received; the power supply loop of the standby power supply is cut off when the first switch signal is received, and the power supply loop of the standby power supply is turned on when the second switch signal is received.

By adopting the technical scheme, the power supply loop of the main power supply is the main power supply loop of the power supply module, and the power supply loop of the standby power supply is the standby power supply loop of the power supply module; the switching unit is used for controlling the on and off functions of the power supply loops of the main power supply and the standby power supply simultaneously, when the main power supply normally operates to supply power to the water meter body and the Internet of things communication module, the voltage detection signal output by the voltage detection module is greater than the threshold voltage signal VREF, the signal comparison unit outputs a first level signal, and the switching unit outputs the first switching signal to control the power supply loops of the standby power supply to be off after receiving the first level signal, namely the standby power supply does not supply power at the moment; when the main power supply is short-circuited, the voltage detection signal output by the voltage detection module is smaller than the threshold voltage signal VREF, the signal comparison unit outputs a second level signal, the switching unit outputs a second switching signal after receiving the second level signal to control the power supply loop of the main power supply to be cut off, the power supply loop of the standby power supply is communicated, namely, the standby power supply supplies power to the water meter body and the Internet of things communication module, and the prompting unit prompts workers that the main power supply is short-circuited at the moment after receiving the second switching signal, so that the workers can maintain the water meter in time, and the maintenance of the water meter is facilitated.

Preferably, the voltage detection unit includes: the voltage detector is electrically connected to the power supply loop of the main power supply.

By adopting the technical scheme, the voltage detector is used for detecting whether the power supply loop of the main power supply is short-circuited, and when the main power supply is normally supplied and the short circuit is not generated, the voltage detector detects that the voltage value of the main power supply is greater than the threshold voltage signal VREF, namely the voltage detection signal is greater than the threshold voltage signal VREF; when the main power supply is short-circuited, the voltage detector detects that the voltage value of the main power supply is smaller than the threshold voltage signal VREF, namely the voltage detection signal is smaller than the threshold voltage signal VREF, so that the voltage detector achieves the functions of detecting the voltage of the main power supply and outputting a voltage detection signal.

Preferably, the signal comparison unit includes: the first signal input end of the comparator N1 is coupled to the voltage detection unit, the second signal input end of the comparator N1 is coupled to the threshold voltage signal VREF, and the signal output end of the comparator N1 is coupled to the switch unit.

By adopting the technical scheme, the first signal input end of the comparator N1 is a positive-phase voltage input end, and the second signal input end of the comparator N1 is an inverse-phase voltage input end; the comparator N1 compares the voltage detection signal received by the first signal input terminal with the threshold voltage signal VREF, and feeds back the result of comparing the voltage detection signal with the threshold voltage signal VREF at the first time: when the voltage detection signal is greater than the threshold voltage signal VREF, the comparator N1 outputs a first type of high-level signal, and when the voltage detection signal is less than the threshold voltage signal VREF, the comparator N1 outputs a second type of low-level signal, so that the comparator N1 realizes the function of comparing the magnitudes of the voltage detection signals.

Preferably, the switching unit includes a first triode Q1 and a relay KM, wherein a base electrode of the first triode Q1 is coupled to a signal output end of the comparator N1, a collector electrode of the first triode Q1 is coupled to a power supply voltage VCC after being connected in series with a coil of the relay KM, an emitter electrode of the first triode Q1 is grounded, and the relay KM includes: the normally open contact switch KM-1 and the normally closed contact switch KM-2 are connected in series in a power supply loop of the main power supply, and the normally closed contact switch KM-2 is connected in series in the power supply loop of the standby power supply.

By adopting the technical scheme, the first triode Q1 is an NPN triode, the first level signal is a high level signal, and the second level signal is a low level signal; when the main power supply does not have a short circuit condition, the base electrode of the first triode Q1 is conducted when receiving a high-level first level signal, the normally open contact switch KM-1 is closed, the main power supply works normally, the normally closed contact switch KM-2 is opened, and the standby power supply does not work; when the main power supply is in a short circuit condition, the base electrode of the first triode Q1 is cut off when receiving a low-level second-class level signal, the normally open contact switch KM-1 is kept in an open state, namely a power supply loop of the main power supply is opened, and at the moment, the normally closed contact switch KM-2 is closed, and the standby power supply works.

Preferably, the prompting unit includes: the base electrode of the second triode Q2 is coupled to the signal output end of the comparator N1, the emitter electrode of the second triode Q2 and the prompter HA are connected in series and then coupled to the power supply voltage VCC, and the collector electrode of the second triode Q2 is grounded.

By adopting the technical scheme, the second triode Q2 is a PNP triode, the base electrode of the second triode Q2 is cut off when receiving a high-level first-class level signal, and the prompter HA is powered off and does not work; the base electrode of the second triode Q2 is conducted when receiving a low-level second-class level signal, and the prompter HA is conducted and emits an acousto-optic prompting signal.

Preferably, the power supply module includes a synchronous rectification buck converter, the synchronous rectification buck converter is coupled to the water meter body, and the synchronous rectification buck converter is coupled to the internet of things communication module.

Through adopting above-mentioned technical scheme, synchronous rectification buck converter is used for turning into the low-voltage current that water gauge body and thing networking communication module used with high-voltage current.

Preferably, the power supply module is electrically connected with a fuse FU, and the fuse FU is coupled in a power supply loop of the main power supply.

Through adopting above-mentioned technical scheme, fuse FU is used for when the power supply return circuit of main power supply takes place the short circuit, and the electric current is too big and fuse, can cut off the power supply return circuit of main power supply promptly, plays the guard action.

In summary, the present application includes at least one of the following beneficial technical effects:

1. when the power supply module is short-circuited, the voltage of the power supply module is zero, the voltage detection signal output by the voltage detection module is smaller than the threshold voltage signal VREF, the signal comparison unit outputs a second level signal, the switching unit outputs a second switching signal to control the power supply loop of the power supply module to be cut off after receiving the second level signal, namely the power supply module stops supplying power, the prompting unit outputs an acousto-optic prompting signal to prompt a worker to detect that the voltage of the power supply module is zero at the moment, and the power supply module needs to be maintained or replaced in time, so that the situation that the power supply module continues to operate under the condition of short circuit to damage a water meter is effectively prevented, and the remote communication water meter is protected conveniently when the remote communication water meter is short-circuited;

2. when the main power supply is short-circuited, the switch unit receives the second-class level signal and then outputs a second switch signal to control the power supply loop of the main power supply to cut off, and the power supply loop of the standby power supply is communicated, namely, the standby power supply supplies power to the water meter body and the communication module of the Internet of things at the moment, and the prompt unit prompts workers that the main power supply is short-circuited at the moment after receiving the second switch signal so as to facilitate the workers to maintain in time;

3. the fuse FU is used for fusing when the power supply loop of the main power supply is short-circuited, namely, the power supply loop of the main power supply can be cut off, and the protection function is achieved.

Drawings

Fig. 1 is a schematic diagram of an overall mounting structure of an embodiment of the present application.

Fig. 2 is a circuit diagram of a power protection module in an embodiment of the present application.

Reference numerals illustrate:

1. a water meter body; 2. a power supply module; 21. a synchronous rectification buck converter; 22. a main power supply; 23. a standby power supply; 3. the communication module of the Internet of things; 4. a voltage detection unit; 5. a signal comparison unit; 6. a switching unit; 7. and a prompting unit.

Detailed Description

The present application is described in further detail below in conjunction with figures 1-2.

The embodiment of the application discloses a remote communication water meter based on NB-iot communication. Referring to fig. 1 and 2, a remote communication water meter based on NB-iot communication includes awater meter body 1, apower supply module 2 and an internet ofthings communication module 3, wherein thepower supply module 2 is installed on thewater meter body 1, the internet ofthings communication module 3 is installed on thewater meter body 1, and thepower supply module 2 is used for supplying power to the internet ofthings communication module 3 and thewater meter body 1; thepower supply module 2 comprises a synchronousrectification buck converter 21, and the synchronousrectification buck converter 21 is a synchronous rectification buck converter CE8510; thecommunication module 3 of the Internet of things comprises an M5311 chip; the current of the power supply module enters from the VIN pin of the synchronousrectification buck converter 21, the synchronousrectification buck converter 21 converts 12V current into 3V current for an M5311 chip, and the synchronousrectification buck converter 21 outputs the piezoelectric power to thewater meter body 1 and the Internet ofthings communication module 3 through the SW pin; the remote communication water meter also comprises a power supply protection module, wherein the power supply protection module comprises avoltage detection unit 4, asignal comparison unit 5, aswitch unit 6 and aprompt unit 7.

Referring to fig. 1 and 2, thepower supply module 2 includes amain power supply 22 and astandby power supply 23, a power supply loop of themain power supply 22 forms a main power supply loop of thepower supply module 2, and a power supply loop of thestandby power supply 23 forms a standby power supply loop of thepower supply module 2, so that thepower supply module 2 includes two power supply loops of the main power supply loop and the standby power supply loop; the synchronousrectification buck converter 21 is provided with two, wherein one synchronousrectification buck converter 21 is electrically connected with themain power supply 22; the other synchronousrectification buck converter 21 is electrically connected to abackup power supply 23; themain power supply 22 is coupled to thewater meter body 1, themain power supply 22 and thewater meter body 1 are positioned in an independent power supply loop, thestandby power supply 23 is coupled to thewater meter body 1, thestandby power supply 23 and thewater meter body 1 are positioned in an independent power supply loop, and themain power supply 22 and thestandby power supply 23 are connected in parallel; the fuse FU is electrically connected in the power supply loop of themain power supply 22, the fuse FU is coupled in the power supply loop of themain power supply 22, and the fuse FU is used for fusing when themain power supply 22 is in short circuit so as to cut off the power supply loop of themain power supply 22, thereby playing a role in protecting themain power supply 22; the power supply loop of thepower supply module 2 is electrically connected with a normally closed button SB, and when the normally closed button SB is disconnected, the power supply loops of themain power supply 22 and thestandby power supply 23 are simultaneously disconnected, so that a worker can conveniently press the normally closed button SB during maintenance, and the maintenance work safety is improved.

Referring to fig. 2, thevoltage detection unit 4 is configured to detect a voltage of themain power supply 22 and emit a voltage detection signal; thevoltage detection unit 4 comprises a voltage detector electrically connected in the supply loop of themain power supply 22.

Referring to fig. 2, thesignal comparing unit 5 is coupled to thevoltage detecting unit 4 to receive the voltage detecting signal and is provided with a threshold voltage signal VREF, thesignal comparing unit 5 compares the voltage detecting signal with the threshold voltage signal VREF and outputs a comparison signal, the comparison signal includes a first type of level signal and a second type of level signal, the first type of level signal is a high level signal, and the second type of level signal is a low level signal; thesignal comparison unit 5 comprises a comparator N1, wherein a first signal input end of the comparator N1 is a positive voltage input end, and a second signal input end of the comparator N1 is an inverse voltage input end; the first signal input end of the comparator N1 is coupled to thevoltage detection unit 4, the second signal input end of the comparator N1 is coupled to the threshold voltage signal VREF, and the signal output end of the comparator N1 is coupled to theswitching unit 6.

Referring to fig. 2, theswitching unit 6 is coupled to thesignal comparing unit 5 and is connected in series in the power supply loop of thepower supply module 2, so as to output a switching signal after receiving the comparing signal, wherein the switching signal comprises a first switching signal and a second switching signal, theswitching unit 6 outputs the first switching signal when receiving the first level signal, theswitching unit 6 outputs the second switching signal when receiving the second level signal, the power supply loop of thepower supply module 2 is turned on when receiving the first switching signal, and the power supply loop of thepower supply module 2 is turned off when receiving the second switching signal; theswitch unit 6 comprises a first triode Q1 and a relay KM, wherein the first triode Q1 is an NPN triode; the base of the first triode Q1 is coupled to the signal output end of the comparator N1, the collector of the first triode Q1 is coupled to the power supply voltage VCC after being connected in series with the coil of the relay KM, the emitter of the first triode Q1 is grounded, the relay KM comprises a normally open contact switch KM-1 and a normally closed contact switch KM-2, the normally open contact switch KM-1 is connected in series in a power supply loop of themain power supply 22, and the normally closed contact switch KM-2 is connected in series in the power supply loop of thestandby power supply 23, so that themain power supply 22, the fuse, thewater meter body 1 and the Internet ofthings communication module 3 form an independent main power supply loop, and thestandby power supply 23, thewater meter body 1 and the Internet ofthings communication module 3 form an independent standby power supply loop.

Referring to fig. 2, theprompting unit 7 is coupled to theswitch unit 6 and emits an acousto-optic prompting signal when receiving the second switch signal; theprompting unit 7 comprises a second triode Q2 and a prompting device HA, wherein the second triode Q2 is a PNP triode; the base electrode of the second triode Q2 is coupled to the signal output end of the comparator N1, the emitter electrode of the second triode Q2 is coupled to the power supply voltage VCC after being connected in series with the prompter HA, and the collector electrode of the second triode Q2 is grounded; when themain power supply 22 is short-circuited, the voltage detection signal output by the voltage detector is smaller than the threshold voltage signal VREF, the base of the second triode Q2 receives a low-level second-class level signal, the second triode Q2 is conducted, and the prompter HA is powered on and emits sound to prompt a worker that themain power supply 22 is short-circuited at the moment.

The implementation principle of the remote communication water meter based on NB-iot communication is as follows: when themain power supply 22 in thepower supply module 2 normally operates without short circuit, the voltage value of themain power supply 22 detected by the voltage detector is larger than a threshold voltage signal VREF, namely the voltage detection signal of the positive input end of the comparator N1 is larger than the threshold voltage signal VREF of the negative input end of the comparator N1, the signal output end of the comparator N1 outputs a high-level first level signal to the base electrode of the first triode Q1, the first triode Q1 is conducted, the coil of the relay KM is electrified, the normally open contact switch KM-1 is closed, the normally closed contact switch KM-2 is opened, namely the power supply loop of themain power supply 22 is conducted at the moment, the power supply loop of thestandby power supply 23 is cut off, and thestandby power supply 23 does not work; and at the moment, when the base electrode of the second triode Q2 receives a high-level first-class level signal, the signal is cut off, and the prompter HA does not work; when the power supply loop of themain power supply 22 is short-circuited, the voltage of themain power supply 22 is reduced, the voltage value detected by the voltage detector is smaller than a threshold voltage signal VREF, namely the voltage detection signal of the positive input end of the comparator N1 is smaller than the threshold voltage signal VREF of the negative input end of the comparator N1, the signal output end of the comparator N1 outputs a low-level second-class level signal to the base electrode of the first triode Q1, the first triode Q1 is cut off, the coil of the relay KM is not electrified, the normally open contact switch KM-1 is kept in an open state, the normally closed contact switch KM-2 is kept closed, namely the power supply loop of themain power supply 22 is cut off at the moment, the power supply loop of thestandby power supply 23 is conducted, and thestandby power supply 23 starts to operate so as to continuously supply power for thewater meter body 1 and the Internet ofthings communication module 3; and the base electrode of the second triode Q2 is conducted when receiving a second class level signal of low level, and the prompter HA starts operation to prompt the staff that themain power supply 22 is short-circuited and needs to be maintained in time, so that thepower supply module 2 is protected.

The foregoing are all preferred embodiments of the present application, and are not intended to limit the scope of the present application in any way, therefore: all equivalent changes in structure, shape and principle of this application should be covered in the protection scope of this application.

Claims (8)

1. A telecommunications water meter based on NB-iot communications, comprising: water gauge body (1), power module (2) and thing networking communication module (3), power module (2) install in water gauge body (1), thing networking communication module (3) install in water gauge body (1), power module (2) are used for to thing networking communication module (3) with water gauge body (1) power supply, its characterized in that, power module (2) include: the remote communication water meter further comprises a power protection module, wherein the power protection module comprises:

the voltage detection unit (4) is used for detecting the voltage of the main power supply loop of the power supply module (2) and sending out a voltage detection signal;

a signal comparing unit (5) coupled to the voltage detecting unit (4) to receive the voltage detecting signal and provided with a threshold voltage signal VREF, the signal comparing unit (5) comparing the voltage detecting signal with the threshold voltage signal VREF and outputting a comparison signal, the comparison signal including a first type level signal and a second type level signal;

the switch unit (6) is coupled to the signal comparison unit (5) and is sequentially connected in series in the main power supply loop and the standby power supply loop of the power supply module (2) so as to output a switch signal after receiving the comparison signal, wherein the switch signal comprises: a first switching signal and a second switching signal, wherein the switching unit (6) outputs the first switching signal when receiving the first level signal, the switching unit (6) outputs the second switching signal when receiving the second level signal, the main power supply loop of the power supply module (2) is conducted when receiving the first switching signal, and the standby power supply loop of the power supply module (2) is cut off when receiving the first switching signal; the main power supply loop of the power supply module (2) is cut off when the second switch signal is received, and the standby power supply loop of the power supply module (2) is turned on when the second switch signal is received;

and the prompting unit (7) is coupled with the switch unit (6) and sends out an acousto-optic prompting signal when receiving the second switch signal.

2. The NB-iot communication based remote communication water meter of claim 1, wherein the power supply module (2) comprises a main power supply (22) and a standby power supply (23), the main power supply (22) is coupled to the water meter body (1), the main power supply (22) and the water meter body (1) are located in a separate power supply circuit, the standby power supply (23) is coupled to the water meter body (1), the standby power supply (23) and the water meter body (1) are located in a separate power supply circuit, the power supply circuit of the main power supply (22) is turned on when the first switch signal is received, and the power supply circuit of the main power supply (22) is turned off when the second switch signal is received; the power supply loop of the standby power supply (23) is turned off when the first switching signal is received, and the power supply loop of the standby power supply (23) is turned on when the second switching signal is received.

3. The NB-iot communication based remote communication water meter according to claim 2, wherein the voltage detection unit (4) comprises: and the voltage detector is electrically connected to the power supply loop of the main power supply (22).

4. The NB-iot communication based remote water meter as claimed in claim 2, wherein the signal comparison unit (5) comprises: the first signal input end of the comparator N1 is coupled to the voltage detection unit (4), the second signal input end of the comparator N1 is coupled to the threshold voltage signal VREF, and the signal output end of the comparator N1 is coupled to the switching unit (6).

5. The NB-iot communication based remote communication water meter of claim 4, wherein the switching unit (6) comprises a first transistor Q1 and a relay KM, a base of the first transistor Q1 is coupled to the signal output terminal of the comparator N1, a collector of the first transistor Q1 is coupled to a power supply voltage VCC after being connected in series with a coil of the relay KM, an emitter of the first transistor Q1 is grounded, and the relay KM comprises: the normally open contact switch KM-1 and the normally closed contact switch KM-2 are connected in series in a power supply loop of the main power supply (22), and the normally closed contact switch KM-2 is connected in series in a power supply loop of the standby power supply (23).

6. The NB-iot communication based remote water meter according to claim 5, wherein the prompt unit (7) comprises: the base electrode of the second triode Q2 is coupled to the signal output end of the comparator N1, the emitter electrode of the second triode Q2 and the prompter HA are connected in series and then coupled to the power supply voltage VCC, and the collector electrode of the second triode Q2 is grounded.

7. The NB-iot communication based remote communication water meter of claim 2, wherein the power supply module (2) comprises a synchronous rectification buck converter (21), the synchronous rectification buck converter (21) being coupled to the water meter body (1), the synchronous rectification buck converter (21) being coupled to the internet of things communication module (3).

8. The NB-iot communication based remote water meter of claim 7, wherein the power module (2) is electrically connected to a fuse FU, the fuse FU being coupled in a power loop of the main power supply (22).

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