A temperature controller switch quantity detection device

Abstract

A thermostat switch quantity detection device includes a plurality of detection circuit modules with independent power supply and ground system, wherein the detection circuit module includes a detection circuit unit and a comparison circuit unit; the input end of the detection circuit unit is connected to the thermostat switch as the input end of the detection circuit module; the output end of the detection circuit unit is connected to the input end of the comparison circuit unit; the output end of the comparison circuit unit is used as the output end of the detection circuit module. The detection circuit unit uses a plurality of diodes to form a detection circuit, thereby ensuring the safety of the device under test and the test equipment; it can be powered and simultaneously determine the on-off status of multiple groups of switch quantities, and will not cause equipment damage due to a short circuit caused by a pair of contacts being reversely connected, thereby improving detection efficiency, saving test time, maintaining the normal operation of the transformer system, and ensuring production and detection efficiency.

Description

Technical Field

[0001] The invention relates to the field of switch quantity detection of transformer winding temperature controller, and in particular to a switch quantity detection device of a temperature controller. Background Art

[0002] The transformer winding thermostat is a special instrument used to measure and control the temperature of the transformer winding. It is used to measure the temperature of the transformer winding, and also has multiple functions such as starting and stopping the transformer cooling system, warning signal alarm and accident tripping, so as to realize remote monitoring and control of the transformer operating conditions. It is one of the important protection devices for the transformer. Accurately verifying the action point of the thermostat switch quantity is an important part of the verification of the transformer temperature control system, which can effectively protect the transformer and extend the service life of the transformer.

[0003] At present, the traditional switch quantity detection method is to conduct qualitative detection on the switch quantity signal level range and detect its high and low levels. However, in the switch quantity detection of the transformer temperature controller, live detection may occur, and the AC / DC voltage is as high as 200+V, which is unbearable for the sampling resistor, and there are many situations for the live state / type of the switch contacts. If a simple high and low level judgment method is used, it is easy for the detection circuit to burn out without power failure; if the power is off, the test equipment and even the entire transformer system will be shut down, which greatly affects the efficiency of production and detection. In addition, when the existing scheme detects multiple switch quantities at the same time, it performs common ground processing. At this time, if one of the contacts is connected in reverse, the high end of the power supply and the ground are short-circuited, which will cause damage to the device under test. Summary of the invention

[0004] In order to solve the above problems, a thermostat switch quantity detection device is provided, which includes several detection circuit modules with independent power supply and ground system, and the detection circuit module includes a detection circuit unit and a comparison circuit unit; the input end of the detection circuit unit is connected to the thermostat switch as the input end of the detection circuit module; the output end of the detection circuit unit is connected to the input end of the comparison circuit unit; the output end of the comparison circuit unit is used as the output end of the detection circuit module. The detection circuit unit uses multiple diodes to form a detection circuit, which ensures the safety of the device under test and the test equipment; it can be powered and judge the on-off status of multiple groups of switch quantities at the same time, and will not cause short circuit and equipment damage due to reverse connection of a pair of contacts, thereby improving detection efficiency, saving test time, maintaining the normal operation of the transformer system, and ensuring production and detection efficiency.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A temperature controller switch quantity detection device includes a plurality of detection circuit modules with independent power supply and ground system, wherein the detection circuit module includes a detection circuit unit and a comparison circuit unit; the input end of the detection circuit unit is connected to the temperature controller switch as the input end of the detection circuit module; the output end of the detection circuit unit is connected to the input end of the comparison circuit unit; the output end of the comparison circuit unit is used as the output end of the detection circuit module; the detection circuit unit uses a plurality of diodes to form a detection circuit.

[0007] Furthermore, the detection circuit unit includes a diode D1, a diode D2, a diode D3, a diode D4, a diode D5 and a resistor R1; the cathode of the diode D1 is connected to the cathode of the diode D2 and serves as an input end of the detection circuit unit; the anode of the diode D1 is connected to one end of the resistor R1 and the cathode of the diode D4 and serves as an output end K-NE of the detection circuit unit and is connected to the input end of the comparison circuit unit; the anode of the diode D2 is connected to the cathode of the diode D3; the anode of the diode D3 is connected to the anode of the diode D4 and the anode of the diode D5 and serves as another input end of the detection circuit unit; the cathode of the diode D5 is connected to the reference ground GND, and the other end of the resistor R1 is connected to the power supply; the two input ends of the detection circuit unit are respectively connected to the two ends of the thermostat switch.

[0008] Furthermore, the comparison circuit unit includes a first comparator LM1, a second comparator LM2, a resistor R3 and a resistor R4; the positive input terminal of the first comparator LM1 and the inverting input terminal of the second comparator LM2 are respectively connected to the output terminal of the detection circuit unit as the input terminals of the comparison circuit unit; the inverting input terminal of the first comparator LM1 is connected to the power supply, and the positive input terminal of the second comparator LM2 is connected to the power supply; the output terminal of the first comparator LM1 is connected to one end of the resistor R3 and serves as the first output terminal K-NE-1 of the comparison circuit unit; the output terminal of the second comparator LM2 is connected to one end of the resistor R4 and serves as the second output terminal K-NE-2 of the comparison circuit unit; the other end of the resistor R3 is connected to the power supply, and the other end of the resistor R4 is connected to the power supply; the first output terminal K-NE-1 and the second output terminal K-NE-2 serve as the output terminals of the detection circuit module.

[0009] Furthermore, the diode D1 , the diode D2 , the diode D3 , the diode D4 and the diode D5 have the same conduction voltage drop.

[0010] Furthermore, the power supply voltage connected to the inverting input terminal of the first comparator LM1 is higher than the power supply voltage connected to the non-inverting input terminal of the second comparator LM2; the output terminal voltage of the detection circuit unit is between the power supply voltage connected to the inverting input terminal of the first comparator LM1 and the power supply voltage connected to the non-inverting input terminal of the second comparator LM2.

[0011] Furthermore, the other end of the resistor R3 is connected to the same power supply voltage as the other end of the resistor R4; the resistance values ​​of the resistor R3 and the resistor R4 are the same; and the first comparator LM1 and the second comparator LM2 are the same. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the structure of the detection circuit unit;

[0013] Figure 2 It is a schematic diagram of the structure of the comparison circuit unit. DETAILED DESCRIPTION

[0014] The embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.

[0015] The following describes the embodiments of the present disclosure through specific examples, and those skilled in the art can easily understand other advantages and effects of the present disclosure from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all of the embodiments. The present disclosure can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present disclosure. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present disclosure.

[0016] Embodiment 1

[0017] A temperature controller switch value detection device includes a plurality of detection circuit modules, wherein the detection circuit modules include a detection circuit unit and a comparison circuit unit. Figure 1As shown, the detection circuit unit includes a diode D1, a diode D2, a diode D3, a diode D4, a diode D5 and a resistor R1. The cathode of the diode D1 is connected to the cathode of the diode D2 as an input terminal of the detection circuit unit; the anode of the diode D1 is connected to one end of the resistor R1 and the cathode of the diode D4 as an output terminal K-NE of the detection circuit unit; the anode of the diode D2 is connected to the cathode of the diode D3; the anode of the diode D3 is connected to the anode of the diode D4 and the anode of the diode D5 as another input terminal of the detection circuit unit; the cathode of the diode D5 is connected to the reference ground GND, and the other end of the resistor R1 is connected to the power supply; the two input terminals of the detection circuit unit serve as the two input terminals of the detection circuit module.

[0018] like Figure 2 As shown, the comparison circuit unit includes a first comparator LM1, a second comparator LM2, a resistor R3, and a resistor R4, and the output terminal K-NE is respectively connected to the positive input terminal of the first comparator LM1 and the inverting input terminal of the second comparator LM2; the inverting input terminal of the first comparator LM1 is connected to the power supply, and the positive input terminal of the second comparator LM2 is connected to the power supply; the output terminal of the first comparator LM1 is connected to one end of the resistor R3 and serves as the first output terminal K-NE-1 of the comparison circuit unit; the output terminal of the second comparator LM2 is connected to one end of the resistor R4 and serves as the second output terminal K-NE-2 of the comparison circuit unit; the other end of the resistor R3 is connected to the power supply, and the other end of the resistor R4 is connected to the power supply; the first output terminal K-NE-1 and the second output terminal K-NE-2 serve as the output terminals of the detection circuit module.

[0019] In a specific implementation, the two input ends of each detection circuit module are respectively connected to the two ends of a thermostat switch K to be detected, and the switch K is connected in series with the load resistor R2; when detecting multiple switch quantities of the thermostat at the same time, each detection circuit module uses its own independent power supply and ground system, which are isolated from each other to ensure the safety and reliability of simultaneous measurement of different switch quantities under any wiring state, and prevent equipment damage caused by reverse short circuit.

[0020] In the specific implementation, in terms of device selection, it is necessary to select diodes D1, D2, D3, D4 and D5 with sufficient overcurrent capacity and reverse breakdown voltage according to the load loop current of the external switch and the power supply voltage to prevent damage to the detection circuit due to excessive voltage and current.

[0021] In a specific implementation, the diode D1 , the diode D2 , the diode D3 , the diode D4 and the diode D5 have the same conduction voltage drop.

[0022] In a specific implementation, the power supply voltage connected to the inverting input terminal of the first comparator LM1 is higher than the power supply voltage connected to the non-inverting input terminal of the second comparator LM2; the output terminal voltage of the detection circuit unit is between the power supply voltage connected to the inverting input terminal of the first comparator LM1 and the power supply voltage connected to the non-inverting input terminal of the second comparator LM2.

[0023] In a specific implementation, the other end of the resistor R3 is connected to the same power supply voltage as the other end of the resistor R4; the resistance values ​​of the resistor R3 and the resistor R4 are the same; and the first comparator LM1 and the second comparator LM2 are the same.

[0024] The following is an example using a specific access voltage value:

[0025] Assuming that the power supply voltage UAB of the external load circuit is 200V and the other end of the resistor R1 is connected to a 5V power supply, when the external load circuit is in different states, the following 8 different situations will occur:

[0026] (1) When the switch K is not connected to the external load circuit, that is, the two ends of the switch K are not energized and are in the disconnected state, the detection circuit unit cannot form a current path, and the output terminal K-NE signal is 5V.

[0027] (2) When switch K is not connected to the external load circuit, that is, the two ends of switch K are not energized and are in a connected state, diodes D1 and D5 are turned on, and the current of the detection circuit unit flows back to the reference ground GND through resistor R1, diode D1, switch K and diode D5; the impedance of switch K is at the mΩ level, and the voltage drop across the two ends is at the mV level, which can be ignored; at this time, the amplitude of the output terminal K-NE signal is the sum of the conduction voltage drops of diodes D1 and D5, which is about 1.4V.

[0028] (3) When UAB=200VDC, switch K is connected to the external load circuit, that is, both ends of switch K are energized and in the disconnected state, the detection circuit unit cannot form a current path, and the output terminal K-NE signal is 5V.

[0029] (4) When UAB = 200 VDC, switch K is connected to the external load circuit, that is, both ends of switch K are energized and in the connected state, then diode D1 and diode D5 are turned on, and the current of the detection circuit unit flows back to the reference ground GND through resistor R1, diode D1, switch K and diode D5; the impedance of switch K is at the mΩ level, and the voltage drop across the two ends is at the mV level, which can be ignored; the amplitude of the output terminal K-NE signal is the sum of the conduction voltage drops of diodes D1 and D5, which is about 1.4 V.

[0030] (5) When UAB = -200 VDC, switch K is connected to the external load circuit, that is, both ends of switch K are energized and in the disconnected state, then diodes D4 and D5 are turned on, the potential difference between the anode of diode D4 and the output terminal K-NE is the conduction voltage drop of diode D4, and the potential difference between the anode of diode D4 and the reference ground GND is the conduction voltage drop of diode D5. Under the premise of selecting diodes of the same type, the conduction voltage drops are equal, so the output terminal K-NE and the reference ground GND are at the same potential, that is, 0 V.

[0031] (6) UAB = -200 VDC, switch K is connected to the external load circuit, that is, both ends of switch K are energized and in a connected state. At this time, diodes D1 and D5 are turned on, and the current of the detection circuit unit flows back to the reference ground GND through resistor R1, diode D1, switch K and diode D5. The impedance of switch K is at the mΩ level, and the voltage drop across the two ends is at the mV level, which can be ignored; the amplitude of the output terminal K-NE signal is the sum of the conduction voltage drops of diodes D1 and D5, which is about 1.4 V.

[0032] (7) UAB = 200VAC, switch K is connected to the external load circuit, that is, both ends of switch K are energized and in the disconnected state. Referring to the above examples (3) and (5) where the voltage is positive or negative DC, the output terminal K-NE signal changes repeatedly between 0V and 5V, and its change cycle is the same as the external AC voltage cycle.

[0033] (8) UAB = 200VAC, switch K is connected to the external load circuit, that is, both ends of switch K are energized and in the connected state, at this time, diode D1 and diode D5 are turned on, and the current of the detection circuit unit flows back to the reference GND through resistor R1, diode D1, switch K and diode D5. The impedance of switch K is at the mΩ level, and the voltage drop at both ends is at the mV level, which can be ignored; the amplitude of the output terminal K-NE signal is the sum of the conduction voltage drops of diodes D1 and D5, which is about 1.4V.

[0034] As can be seen from the above, corresponding to the above 8 different situations, the output terminal K-NE signal has three states of 5V, 1.4V, and 0V alternating. When the switch K is in the connected state, the output terminal K-NE signal is 1.4V.

[0035] The output terminal K-NE signal is compared twice through the first comparator LM1 and the second comparator LM2 of the comparison circuit unit. Assume that the reverse input terminal of the first comparator LM1 is connected to a 3V power supply, and the positive input terminal of the second comparator LM2 is connected to a 0.5V power supply. When the output terminal K-NE is greater than +3V, the first output terminal K-NE-1 is at a high level, and the switch K can be judged to be disconnected; when the output terminal K-NE is less than +3V, the first output terminal K-NE-1 is at a low level, and a second comparison is performed. If +3V>output terminal K-NE>0.5V, the second output terminal K-NE-2 signal is at a low level, and it can be judged that K-NE=1.4V, so the switch quantity is connected; if the output terminal K-NE is less than 0.5V, the second output terminal K-NE-2 signal is at a high level, and it can be judged that the external load circuit is a negative voltage and the switch K is disconnected. In summary, it is organized in a table as follows:

[0036]

[0037]

[0038] It can be seen that the switch K is connected only when the signals of the first output terminal K-NE-1 and the second output terminal K-NE-2 are both at low level, and the switch K is disconnected in other cases.

[0039] A thermostat switch quantity detection device includes a plurality of detection circuit modules with independent power supply and ground system, wherein the detection circuit module includes a detection circuit unit and a comparison circuit unit; the input end of the detection circuit unit is connected to the thermostat switch as the input end of the detection circuit module; the output end of the detection circuit unit is connected to the input end of the comparison circuit unit; the output end of the comparison circuit unit is used as the output end of the detection circuit module. The detection circuit unit uses a plurality of diodes to form a detection circuit, and the detection circuit can withstand an external load circuit AC / DC voltage of 200+V, thereby ensuring the safety of the device under test and the test equipment; it can be powered and simultaneously determine the on / off status of multiple groups of switch quantities, and will not cause equipment damage due to a short circuit caused by a pair of contacts being reversely connected, thereby improving detection efficiency, saving test time, maintaining the normal operation of the transformer system, and ensuring production and detection efficiency.

[0040] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] The above is only for explaining the implementation mode of the present invention and is not intended to limit the present invention. For those skilled in the art, any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention without creative work should be included in the protection scope of the present invention.

Claims

1. A temperature controller switch quantity detection device, characterized in that: It includes several detection circuit modules with independent power supply and ground system, and the detection circuit module includes a detection circuit unit and a comparison circuit unit; the input end of the detection circuit unit is connected to the thermostat switch as the input end of the detection circuit module; the output end of the detection circuit unit is connected to the input end of the comparison circuit unit; the output end of the comparison circuit unit is used as the output end of the detection circuit module; the detection circuit unit uses multiple diodes to form a detection loop; The detection circuit unit includes a diode D1, a diode D2, a diode D3, a diode D4, a diode D5 and a resistor R1; the cathode of the diode D1 is connected to the cathode of the diode D2 and serves as an input end of the detection circuit unit; the anode of the diode D1 is connected to one end of the resistor R1 and the cathode of the diode D4 and serves as an output end K-NE of the detection circuit unit and is connected to the input end of the comparison circuit unit; the anode of the diode D2 is connected to the cathode of the diode D3; the anode of the diode D3 is connected to the anode of the diode D4 and the anode of the diode D5 and serves as another input end of the detection circuit unit; the cathode of the diode D5 is connected to the reference ground GND, and the other end of the resistor R1 is connected to the power supply; the two input ends of the detection circuit unit are respectively connected to the two ends of the thermostat switch; the conduction voltage drops of the diode D1, the diode D2, the diode D3, the diode D4 and the diode D5 are the same; The comparison circuit unit includes a first comparator LM1, a second comparator LM2, a resistor R3 and a resistor R4; the positive input end of the first comparator LM1 and the negative input end of the second comparator LM2 are respectively connected to the output end of the detection circuit unit as the input ends of the comparison circuit unit; the negative input end of the first comparator LM1 is connected to the power supply, and the positive input end of the second comparator LM2 is connected to the power supply; the output end of the first comparator LM1 is connected to one end of the resistor R3 and serves as the first output end K-NE-1 of the comparison circuit unit; the output end of the second comparator LM2 is connected to one end of the resistor R4 and serves as the second output end K-NE-2 of the comparison circuit unit; The other end of the resistor R3 is connected to a power supply, and the other end of the resistor R4 is connected to a power supply; the first output end K-NE-1 and the second output end K-NE-2 serve as output ends of the detection circuit module; the power supply voltage connected to the other end of the resistor R3 is the same as the power supply voltage connected to the other end of the resistor R4; the resistance values ​​of the resistor R3 and the resistor R4 are the same; the first comparator LM1 and the second comparator LM2 are the same.

2. The temperature controller switch value detection device according to claim 1, characterized in that: The power supply voltage connected to the inverting input terminal of the first comparator LM1 is higher than the power supply voltage connected to the non-inverting input terminal of the second comparator LM2; the output voltage of the detection circuit unit is between the power supply voltage connected to the inverting input terminal of the first comparator LM1 and the power supply voltage connected to the non-inverting input terminal of the second comparator LM2.

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