Transmission device capable of adjusting transmitted signal strength

Abstract

A transmission device 2 for testing electrical wiring is capable of adjusting a transmitted signal strength using a phase control method. The device comprises: a power supply 24, a microcontroller 20,

Description

BACKGROUND OF THE INVENTION a) Field of the Invention The invention relates to a transmission device, and more particularly to a transmission device capable of adjusting a transmitted signal strength. b) Description of the Prior Art In the power distribution design of a building, the electric power provided by a power company is introduced into the distribution box for distribution. The circuit breaker finder device is used for single-phase 3-wire 110V detection. The signal input device connected to the outlet produces changes in a current signal, it can also be used alone to detect whether the wiring status of the outlet is correct; the signal receiving device searches or compares the circuit breaker finder devices one by one through the sensing part to find out the circuit breaker finder device to which a loop of the outlet connected to the signal input device is connected. The circuit breaker finder device is provided with a signal transmission device (transmitter) and a receiving device (receiver). The transmitter is a signal transmission device, which is connected to the socket where the line loop is to be found, and uses the power source of the socket as the power supply. The transmitter is used to send line hunting signals in the mains power circuit. The receiver is a signal receiving device, mainly used for non-contact search of a signal strength transmitted by the transmitter to the no fuse breaker (NFB) via the socket in order to find the correct loop between the socket and the no fuse breaker. The receiver line hunting function can include other functions, for example, the line hunting function includes comparison mode, which can find the correct loop among loops with very close signals to improve detection of the correct loop, and can also include non-contact voltage detection (similar to the function of a tester pen). The conventional transmitter of circuit breaker finder generally uses a capacitor as a load, for example, the circuit identification device disclosed in the U.S. Patent No. 8,599,029. Also referring to FIG. 1, a periodic power-off module 19 is connected to two wires 12, 13 of a halfsine pulse generation module 18. The periodic power-off module 19 comprises a silicon controlled rectifier (SCR) 193, which a silicon diode for controlling current; after the periodic power-off module 19, a signal transmission module 110 having a capacitor 112 and a resistor 114 is provided. A voltage trigger switch (SIDAC) 192 and a capacitor 191 are connected in series through a wire. When the silicon controlled rectifier 193 is charged by part of the current and reaches a certain voltage, the voltage trigger switch (SIDAC) 192 is conducted, and the current immediately flows into the silicon controlled rectifier 193. Therefore, the silicon controlled rectifier 193 is characterized by periodic short power outages. That is, power on immediately after a short power outage. It can be known from the above that the existing method is to use a voltage trigger switch (SIDAC) or a silicon controlled rectifier (SCR) for signal transmission. The advantage is that the strength of signal transmission is very high. The reason why the signal strength is high mainly lies in the voltage phase range of the voltage trigger switch 192 being fixed, so the trigger point of the current cannot be changed. Therefore, when the silicon controlled rectifier 193 completes charging and discharging, it will be charged and discharged again immediately, resulting in multiple charges and discharges occurring in the voltage phase range again. Since the control mode of this type of line hunter is fixed with the signal frequency and phase synchronized with AC, it is inconvenient to adjust the signal strength. The signal may be too strong, which is a big challenge in terms of EMI, or the signal may be too weak, making it difficult to use. According to the above method, the circuit breaker finder device will send a strong signal, and the EMI interference of this signal will not be able to pass the electromagnetic compatibility certification and the Federal Communications Commission certification, resulting in being unable to be exported to countries that require the relevant certifications. The detailed features and advantages of the invention will be described in detail in the following embodiments. The content is sufficient to enable any person having ordinary skill in the art to understand the technical content of the invention and implement it accordingly, and in accordance with the content, the claims and the drawings disclosed in this specification, any person having ordinary skill in the art can easily understand the related objects and advantages of the invention. SUMMARY OF THE INVENTION A main object of the invention lies in: a transmitter is connected to a socket where a line loop is to be found, and uses a power source of the socket as a power supply; the transmitter is used to send a line hunting signal in a mains power circuit, and the signal transmitter is capable of controlling a transmitted signal strength, thereby a transmission device still has enough energy for a receiver to find a signal in a condition of generating low EMI signals. In order to achieve the above object, the invention is a transmission device capable of adjusting a transmitted signal strength, and comprising: a microcontroller unit comprising a zero crossing detector electrically connected to a mains power and capable of detecting a phase with a positive half cycle and a negative half cycle based on an alternating current of the mains power, a frequency counter coupled to the zero crossing detector and capable of detecting a frequency range of the alternating current, an angular timer capable of defining a phase angle range based on a phase of the positive half cycle, and setting a preset trigger point located in the phase angle range, and a thyristor phase controller coupled to the angular timer and capable of generating a current driving signal based on the preset trigger point; a thyristor (TRIAC OR SCR) coupled to the thyristor phase controller and capable of generating a current conduction start signal through receiving the current driving signal; a voltage trigger switch (SIDAC) coupled to the thyristor and capable of defining a voltage phase range and a current stop point located in the voltage phase range, and the voltage phase range between the phase angle range of the alternating current can be triggered by the current conduction start signal to define a current trigger point; and a load capacitor coupled to the voltage trigger switch, the voltage trigger switch determines a position of the current stop point located in the phase angle range, and then the thyristor determines a position of the current trigger point located in the voltage phase range for adjusting a position of a one-time current charging of the load capacitor located in the phase angle range and generating a pulse wave. According to one embodiment of the invention, further comprising a variable resistor coupled to the angular timer and capable of adjusting a position of the preset trigger point in the phase angle range. According to one embodiment of the invention, wherein the phase angle range defines an ascending zone and a descending zone, and an interval from the current trigger point to the current stop point is located in the ascending zone or the descending zone. According to one embodiment of the invention, further comprising a discharge resistor coupled to the load capacitor and capable of releasing electric energy simultaneously when the load capacitor stores electric energy, and a released electric energy is lower than a stored electric energy. According to one embodiment of the invention, further comprising a diode coupled to the load capacitor and capable of generating the pulse wave in the positive half cycle. According to one embodiment of the invention, further comprising a power source supply connected to the mains power to convert the alternating current into a direct current to drive the microcontroller unit. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic circuit diagram of a transmitter of a conventional circuit breaker finder device. FIG. 2 is a schematic circuit diagram of a preferred embodiment of the invention. FIG. 3 is a block diagram of the circuit. FIG. 4 is a schematic operation diagram of waveform of a voltage trigger switch in a positive half cycle. FIG. 5 is a schematic operation diagram of waveform of a thyristor triggering the voltage trigger switch. FIG. 6 is a schematic diagram of application of a transmission device of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following specific embodiments illustrate the implementation mode of the invention. Any person having ordinary skill in the art can easily understand the other advantages and efficacies of the invention from the content disclosed in this specification. The structures, proportions and sizes depicted in the accompanied drawings in this specification are only used to match with the content disclosed in the specification for understanding and reading by those skilled in the art, and are not intended to limit the conditions that can be implemented by the invention, and therefore are not technically significant. Any structural modifications, changes in proportional relationship or adjustment of sizes without affecting the efficacies generated and the objects achieved by the invention, should still fall within the scope covered by the technical content disclosed by the invention. At the same time, the terms such as "one", "two", "above", etc. cited in this specification are only for clarity of description, and are not used to limit the scope of the invention, changes or adjustments in their relative relationships, without substantial changes to the technical content, should also be regarded as the scope of the invention that can be implemented. Please refer to FIG. 2 and FIG. 3 for a schematic circuit diagram of a preferred embodiment of the invention and a block diagram of the circuit respectively. The invention is a transmission device capable of adjusting a transmitted signal strength. A transmission device 2 mainly comprises a microcontroller unit 20, a thyristor (TRIAC OR SCR) 21, a voltage trigger switch (SIDAC) 22 and a load capacitor 23. The transmission device 2 is additionally provided with a power source supply 24. The power source supply 24 is connected to a mains power and converts an alternating current into a direct current to drive the microcontroller unit 20. In addition, the alternating current of the mains power is used to drive the thyristor (TRIAC OR SCR) 21 and the voltage trigger switch (SIDAC) 22, and a phase and a frequency of the alternating current are detected by the microcontroller unit 20. Please refer to FIGS. 4, 5 and 6 for a schematic operation diagram of waveform of a voltage trigger switch in a positive half cycle, a schematic operation diagram of waveform of a thyristor triggering the voltage trigger switch, and a schematic diagram of application of a transmission device of the invention respectively. The microcontroller unit 20 comprises a zero crossing detector 200, a frequency counter 201, an angular timer 202 and a thyristor phase controller 203. The zero crossing detector 200 is electrically connected to the mains power and capable of detecting a phase 3 with a positive half cycle 30 and a negative half cycle 32 (a starting position of the positive and negative half cycles of the alternating current) based on the alternating current of the mains power. The frequency counter 201 is coupled to the zero crossing detector 200 and capable of detecting a frequency range of the alternating current. The angular timer 202 is capable of defining a phase angle range 30a based on a phase of the positive half cycle 30, and setting a preset trigger point 30b (this preset trigger point can be set and triggered by a variable resistor or triggered by a thyristor with a phase preset by a microcontroller program) located in the phase angle range 30a, which is a triggered phase angle position. The thyristor phase controller 203 is coupled to the angular timer 202 and capable of generating a current driving signal based on the preset trigger point 30b. The thyristor (TRIAC OR SCR) 21 is coupled to the thyristor phase controller 203 and capable of generating a current conduction start signal through receiving the current driving signal. The voltage trigger switch (SIDAC) 22 is coupled to the thyristor 21 and capable of defining a voltage phase range 22a and a current stop point 22b (trigger stop point) located in the voltage phase range 22a, and the voltage phase range 22a between the phase angle range 30a of the alternating current can be triggered by the current conduction start signal to define a current trigger point 21a. The load capacitor 23 is coupled to the voltage trigger switch 22, the voltage trigger switch 22 determines a position of the current stop point 22b located in the phase angle range 30a, and then the thyristor 21 determines a position of the current trigger point 21a located in the voltage phase range 22a for adjusting a position of a one-time current charging 23a of the load capacitor 23 located in the phase angle range 30a and generating a pulse wave. Wherein the phase angle range 30a defines an ascending zone 30c and a descending zone 30d (triggering the thyristor 21), and an interval from the current trigger point 21a to the current stop point 22b can be located in the ascending zone 30c or the descending zone 30d. It can be known from the above that the transmission device 2 of the invention uses an electronic switch to control capacitive load operations by a phase control method, and uses charging action of capacitive load to generate a current signal, thereby inducing specific magnetic field changes on an electrical circuit, and then enables a signal receiver to search a line and obtain signal instructions by using magnetic field signals. The transmission device 2 for signals uses a phase control method to provide a signal with a variable signal strength. The transmission device 2 for signals is used to transmit line hunting signals, and a signal transmitter is capable of controlling a strength or a current intensity of a transmitted signal, so that the transmission device 2 is capable of enabling the receiver to find a signal in a condition of generating low EMI signals. It can be known from FIGS. 2 and 3 that the transmission device 2 uses the zero crossing detector 200 (ZCD) built in the microcontroller unit 20 with the software-written frequency counter 201 and the software-written angular timer 202 to detect phase and frequency of an AC voltage to further achieve phase control of a transmitted signal. The variable signal strength method of the transmission device 2 uses the load phase angle range 30a control method, and uses the microcontroller unit 20 to control a load operation time point, so that conducted emissions generated during load operation are reduced to a certain level, which can pass the EMI related tests, but has enough signal strength for the receiver to find a signal. The frequency counter 201 enables a variable signal strength of the transmission device 2 applicable to 50 / 60Hz. The microcontroller unit 20 automatically calculates changes in frequency, automatically synchronizes with an AC input voltage signal and adjusts a phase to the set phase angle range 30a. Then the thyristor (TRIAC OR SCR) 21 is used to control the phase angle range 30a that a load allows to turn on, and the voltage trigger switch (SIDAC) 22 is used to further limit the voltage phase range 22a, which is a conduction angle width. On the other hand, a variable resistor 4 is further comprised, which is coupled to the angular timer 202 and capable of adjusting a position of the preset trigger point 30b in the phase angle range 30a. In addition to triggering a load through a fixed phase angle, the microcontroller unit 20 can also be used to read the variable resistor 4 adjusted by a user on the transmission device 2, and a conversion value of the variable resistor 4 can be used to adjust a triggering angle of the thyristor 21, the angle ranges from 10 degrees to 170 degrees in the positive half cycle 30 and from 190 degrees to 350 degrees in the negative half cycle 32. Since an AC voltage will be different with different phases, a charging current of the load capacitor 23 will be different depending on a voltage. The lower the voltage, the smaller the charging current and the weaker the transmitted signal strength. Therefore, a phase angle can be directly adjusted to adjust a transmitted signal strength. In addition, the load capacitor 23 is connected in parallel with a discharge resistor 5 provided with a function of discharging the load capacitor 23 so that the load capacitor 23 can be recharged after the load capacitor 23 is fully discharged before a next working cycle. When the load capacitor 23 is in the positive half cycle 30 of the phase 3, electric energy is stored and released at the same time. A released electric energy is lower than a stored electric energy, so an accessible electric energy is greater than a released electric energy. When entering the negative half cycle 32, electric energy is fully released to facilitate recharging in a next working cycle. Furthermore, a diode 6 coupled to the load capacitor 23 is capable of generating the pulse wave in the positive half cycle 30. Main switching is controlled by the voltage trigger switch (SIDAC) 22 for charging the load capacitor 23. Charging signals of the load capacitor 23 are used to generate a circuit to induce a large current. Large current signals generate a magnetic field in an AC circuit to enable the receiver to pick up signals with an inductive coil and amplify the signals for search and determination. Through the transmission device 2 of the invention capable of adjusting a transmitted signal strength, program setting can be used to transmit a signal once in each positive half cycle of AC, or a signal can be sent or not sent arbitrarily in an AC cycle. Through program setting, a receiving device 7 (as shown in FIG. 6) can easily identify whether a signal in an AC circuit is generated by the transmission device 2. Not only that, the transmission device 2 can also send on-off keying (OOK) with specific identifiable characteristics. For example: 1-1-0-1-0-0-1-0, 1 means sending a signal, 0 means not sending a signal, and each number is separated by an AC cycle, thereby enabling the receiving device 7 to make interpretations based on on-off keying without making errors in judgment. From the above, it can be known that the transmission device of the invention capable of adjusting a transmitted signal strength mainly uses the phase control method to provide a signal with a variable signal strength for transmitting a line hunting signal, and the transmission device is capable of controlling a strength or a current intensity of a transmitted signal, so that the transmission device is capable of enabling the receiving device to find a signal in a condition of generating low EMI signals.

Claims

1. A transmission device capable of adjusting a transmitted signal strength, comprisinga microcontroller unit comprising a zero crossing detector electrically connected to a mains power and capable of detecting a phase with a positive half cycle and a negative half cycle based on an alternating current of the mains power, a frequency counter coupled to the zero crossing detector and capable of detecting a frequency range of the alternating current, an angular timer capable of defining a phase angle range based on a phase of the positive half cycle, and setting a preset trigger point located in the phase angle range, and a thyristor phase controller coupled to the angular timer and capable of generating a current driving signal based on the preset trigger point;a thyristor coupled to the thyristor phase controller and capable of generating a current conduction start signal through receiving the current driving signal;a voltage trigger switch coupled to the thyristor and capable of defining a voltage phase range and a current stop point located in the voltage phase range, and the voltage phase range between the phase angle range of the alternating current being triggered by the currentconduction start signal to define a current trigger point; anda load capacitor coupled to the voltage trigger switch, the voltage trigger switch determining a position of the current stop point located in the phase angle range, and then the thyristor determining a position of the current trigger point located in the voltage phase range for adjusting a position of a one-time current charging of the load capacitor located in the phase angle range and generating a pulse wave.

2. The transmission device capable of adjusting a transmitted signal strength as claimed in claim 1, further comprising a variable resistor coupled to the angular timer and capable of adjusting a position of the preset trigger point in the phase angle range.

3. The transmission device capable of adjusting a transmitted signal strength as claimed in claim 1, wherein the phase angle range defines an ascending zone and a descending zone, and an interval from the current trigger point to the current stop point is located in the ascending zone or the descending zone.

4. The transmission device capable of adjusting a transmitted signal strength as claimed in claim 1, further comprising a discharge resistor coupled to the load capacitor and capable of releasing electric energy simultaneously when the load capacitor storing electric energy, and areleased electric energy being lower than a stored electric energy.

5. The transmission device capable of adjusting a transmitted signal strength as claimed in claim 1, further comprising a diode coupled to the load capacitor and capable of generating the pulse wave in the positive 5 half cycle.

6. The transmission device capable of adjusting a transmitted signal strength as claimed in claim 1, further comprising a power source supply connected to the mains power to convert the alternating current into a direct current to drive the microcontroller unit.10

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