A sensor disconnection detection and display circuit

Abstract

The application discloses a kind of sensor off-line detection and display circuit, including current sampling circuit, signal amplification circuit, signal conversion circuit and fault display circuit.Current sampling circuit is used to collect the analog voltage signal in the working process of the sensor to be measured, signal amplification circuit is used to amplify the analog voltage signal, signal conversion circuit is used to convert the analog voltage signal into digital voltage signal, and according to the value of digital voltage signal, control LED light in fault display circuit to show whether there is no installation or off-line failure in the sensor to be measured.The new type has good universality, low cost, high reliability, simple principle and the like.

Description

Technical Field

[0001] This invention relates to the technical field of sensor technology detection and signal processing applications, and more specifically to a sensor disconnection detection and display circuit. Background Technology

[0002] Currently, construction hoists, cranes, and other similar equipment have strict weight limits when lifting heavy objects. Such equipment must be equipped with weight limiters and pass relevant industry certifications before being used in the market. When the load exceeds the limit, the hoist or crane will be prohibited from operation to ensure the safe and reliable operation of the equipment. Weight sensors are typically used to implement the weight limiter function, making them an essential component of the system. The system should have prompts and displays indicating when a weight sensor is disconnected or not installed, alerting installation personnel to the malfunction and facilitating timely inspection and repair.

[0003] However, the current method for detecting sensor disconnection generally uses a pull-up resistor connected to the power supply voltage or a pull-down resistor connected to the power supply reference ground. This method is not suitable for some instrument amplifier circuits or applications where connecting pull-up and pull-down resistors to the sensor input stage affects the sampling accuracy.

[0004] Therefore, how to provide a simple, accurate, reliable, and versatile sensor disconnection detection circuit is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a sensor disconnection detection and display circuit, applicable to situations where sensors are connected for signal detection, and used to display whether the sensor is disconnected or not installed during use.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A sensor disconnection detection and display circuit, characterized in that it comprises: a current sampling circuit, a signal amplification circuit, a signal conversion circuit, and a fault display circuit; the input terminal of the current sampling circuit is connected to the terminal block JR1 of the sensor under test, and the output terminal of the current sampling circuit, the signal amplification circuit, the signal conversion circuit, and the fault display circuit are connected in sequence.

[0008] The current sampling circuit is used to acquire the analog voltage signal during the operation of the sensor under test;

[0009] The signal amplification circuit is used to amplify the analog voltage signal;

[0010] The signal conversion circuit is used to convert analog voltage signals into digital voltage signals, and controls the fault display circuit to display whether the sensor under test has a fault of not being installed or being disconnected based on the value of the digital voltage signal.

[0011] Preferably, the fault display circuit is also used to transform the digital voltage signal to adapt to the I / O port level of the controller it interfaces with.

[0012] Preferably, the current sampling circuit includes: a sampling resistor R14; one end of the sampling resistor R14 is connected to the sensor terminal block JR1, and the other end is grounded.

[0013] Preferably, the signal amplification circuit includes: a signal amplifier U2A, capacitors C1 and C3, and resistors R2, R8, R9, R11, and R12; capacitor C1 and resistor R2 are connected in parallel, with one end connected to the negative input terminal of signal amplifier U2A and the other end connected to the output terminal of U2A; one end of resistor R8 is grounded and the other end is connected to the negative input terminal of U2A; one end of resistor R11 is connected to the other end of resistor R14 and the other end is connected to the positive input terminal of U2A; one end of resistor R12 is grounded and the other end is connected to both the positive input terminal of U2A and the other end of resistor R11; one end of resistor R9 is connected to capacitor C3 and the other end is connected to the output terminal of U2A; one end of capacitor C3 is grounded and the other end is connected to resistor R9.

[0014] Preferably, the signal conversion circuit includes: a comparator U1A, a capacitor C2, and resistors R1, R3, R4, R6, R7, and R10; the non-inverting input terminal of comparator U1A is connected to one end of resistor R6 and one end of resistor R1, the other end of resistor R6 is connected to one end of resistor R3 and one end of resistor R4, the other end of resistor R3 is grounded, and the other end of resistor R4 is grounded; the negative-inverting input terminal of comparator U1A is connected to one end of resistor R10, the other end of resistor R10 is connected to one end of resistor R9 and one end of capacitor C3; the output terminal of comparator U1A is connected to the other end of resistor R1 and one end of resistor R7; the other end of resistor R7 is connected to capacitor C2.

[0015] Preferably, the fault display circuit includes: a light-emitting diode LED1, a resistor R5, and a resistor R13; wherein, the positive terminal of the light-emitting diode LED1 is connected to one end of the resistor R13, and the negative terminal is connected to one end of the resistor R5 and one end of the resistor R7 respectively; the other end of the resistor R5 is grounded, and the other end of the resistor R13 is connected to the capacitor C2 and grounded.

[0016] As can be seen from the above technical solution, compared with the prior art, the present invention determines whether the sensor is disconnected or not installed by collecting and converting sensor-related signals, overcoming the situation where sensor abnormalities cannot be identified by pull-up or pull-down resistors, and providing a simple, accurate, reliable and versatile sensor disconnection detection circuit. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0018] Figure 1 This is a block diagram of the sensor disconnection detection and display circuit.

[0019] Figure 2 This is a schematic diagram of a circuit for detecting and displaying sensor disconnection. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] This invention discloses a sensor disconnection detection and display circuit, such as... Figure 1 As shown, it includes: a current sampling circuit, a signal amplification circuit, a signal conversion circuit, and a fault display circuit; the input terminal of the current sampling circuit is connected to the terminal block JR1 of the sensor under test, and the output terminal of the current sampling circuit, the signal amplification circuit, the signal conversion circuit, and the fault display circuit are connected in sequence.

[0022] The current sampling circuit is used to acquire the analog voltage signal during the operation of the sensor under test;

[0023] Signal amplifier circuits are used to amplify analog voltage signals;

[0024] The signal conversion circuit is used to convert analog voltage signals into digital voltage signals, and controls the fault display circuit to display whether the sensor under test has a fault such as not being installed or disconnected based on the value of the digital voltage signal.

[0025] In another embodiment, a level conversion circuit is also included, the input of which is connected to the output of the signal conversion circuit. This level conversion circuit is used to convert the digital voltage signal to adapt to the I / O port level of the controller it interfaces with.

[0026] In one specific embodiment, such as Figure 2 As shown, the current sampling circuit includes: sampling resistor R14; one end of sampling resistor R14 is connected to sensor terminal JR1, and the other end is grounded.

[0027] The signal amplification circuit includes: signal amplifier U2A, capacitors C1 and C3, resistors R2, R8, R9, R11, and R12; capacitor C1 and resistor R2 are connected in parallel, with one end connected to the negative input terminal of signal amplifier U2A and the other end connected to the output terminal of U2A; one end of resistor R8 is grounded and the other end is connected to the negative input terminal of U2A; one end of resistor R11 is connected to the other end of resistor R14, and the other end is connected to the positive input terminal of U2A; one end of resistor R12 is grounded and the other end is connected to both the positive input terminal of U2A and the other end of resistor R11; one end of resistor R9 is connected to capacitor C3 and the other end is connected to the output terminal of U2A; one end of capacitor C3 is grounded and the other end is connected to resistor R9.

[0028] The signal conversion circuit includes: comparator U1A, capacitor C2, resistors R1, R3, R4, R6, R7, and R10; the non-inverting input of comparator U1A is connected to one end of resistor R6 and one end of resistor R1, the other end of resistor R6 is connected to one end of resistor R3 and one end of resistor R4, the other end of resistor R3 is grounded, and the other end of resistor R4 is grounded; the negative input of comparator U1A is connected to one end of resistor R10, the other end of resistor R10 is connected to one end of resistor R9 and one end of capacitor C3; the output of comparator U1A is connected to the other end of resistor R1 and one end of resistor R7; the other end of resistor R7 is connected to capacitor C2.

[0029] The fault display circuit includes: LED1, resistor R5 and resistor R13; wherein, the positive terminal of LED1 is connected to one end of resistor R13, and the negative terminal is connected to one end of resistor R5 and one end of resistor R7 respectively; the other end of resistor R5 is grounded, and the other end of resistor R13 is connected to capacitor C2 and grounded.

[0030] In this embodiment, the sensor's terminal block also provides the power required for the sensor's operation. When the sensor is correctly connected, its operation consumes current, which is converted into a voltage signal through the sampling resistor R14.

[0031] The voltage signal is relatively weak. After being amplified by the signal amplifier circuit U2A, this signal is an analog signal, which the controller cannot directly acquire. Therefore, it needs to be converted into a digital signal that the controller can directly process by the signal conversion circuit U1A.

[0032] Once the sensor is correctly connected, the principle is as follows: Figure 2 As shown, the current consumed by the sensor during operation is greater than the voltage signal at pin 3 of U1A due to the sampling resistor and the amplified voltage signal. Therefore, pin 1 of comparator U1A is at a low level, and LED1 does not light up. When the sensor is disconnected or not connected, the voltage across the sampling resistor R14 is 0V. After signal amplification, this voltage is less than the voltage signal at pin 3 of U1A. Therefore, pin 1 of comparator U1A is at a high level, and LED1 lights up, indicating an abnormal sensor installation.

[0033] In another embodiment, simultaneously, different levels of the comparator U1A's output signal S_D2 represent different sensor states and are uploaded to the controller for identification. A low-level signal indicates a normal sensor connection, while a high-level signal indicates a sensor malfunction; the parameters of R5 / R13 can be adjusted to adapt to a controller with an I / O port level of 3.3V.

[0034] This invention is applicable to scenarios where sensors are used to detect important signals and require indications of sensor disconnection or non-installation, but these issues cannot be identified using pull-up or pull-down resistors. This solution is characterized by its versatility, low cost, high reliability, and simple principle.

[0035] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0036] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A sensor disconnection detection and display circuit, characterized in that, include: Current sampling circuit, signal amplification circuit, signal conversion circuit, and fault display circuit; The input terminal of the current sampling circuit is connected to the terminal block of the sensor under test, and the output terminal of the current sampling circuit, the signal amplification circuit, the signal conversion circuit and the fault display circuit are connected in sequence. The current sampling circuit is used to acquire the analog voltage signal during the operation of the sensor under test; The current sampling circuit includes: a sampling resistor R14; one end of the sampling resistor R14 is connected to the terminal block of the sensor under test, and the other end is grounded; The signal amplification circuit is used to amplify the analog voltage signal. The signal amplification circuit includes: a signal amplifier U2A, capacitors C1 and C3, and resistors R2, R8, R9, R11, and R12. Capacitor C1 and resistor R2 are connected in parallel, with one end connected to the negative input terminal of signal amplifier U2A and the other end connected to the output terminal of U2A. One end of resistor R8 is grounded, and the other end is connected to the negative input terminal of U2A. One end of resistor R11 is connected to the other end of resistor R14, and the other end is connected to the positive input terminal of U2A. One end of resistor R12 is grounded, and the other end is connected to both the positive input terminal of U2A and the other end of resistor R11. One end of resistor R9 is connected to capacitor C3, and the other end is connected to the output terminal of U2A. One end of capacitor C3 is grounded, and the other end is connected to resistor R9. The signal conversion circuit is used to convert analog voltage signals into digital voltage signals, and controls the fault display circuit to display whether the sensor under test has a fault of not being installed or disconnected based on the value of the digital voltage signal. The signal conversion circuit includes: comparator U1A, capacitor C2, resistors R1, R3, R4, R6, R7, and R10; the non-inverting input of comparator U1A is connected to one end of resistor R6 and one end of resistor R1, the other end of resistor R6 is connected to one end of resistor R3 and one end of resistor R4, the other end of resistor R3 is grounded, and the other end of resistor R4 is grounded; the negative-inverting input of comparator U1A is connected to one end of resistor R10, the other end of resistor R10 is connected to one end of resistor R9 and one end of capacitor C3; the output of comparator U1A is connected to the other end of resistor R1 and one end of resistor R7; the other end of resistor R7 is connected to capacitor C2.

2. The sensor disconnection detection and display circuit according to claim 1, characterized in that, The fault display circuit is also used to transform the digital voltage signal to adapt it to the I / O port level of the controller it interfaces with.

3. The sensor disconnection detection and display circuit according to claim 1, characterized in that, The fault display circuit includes: LED1, resistor R5 and resistor R13; wherein, the positive terminal of LED1 is connected to one end of resistor R13, and the negative terminal is connected to one end of resistor R5 and one end of resistor R7 respectively; the other end of resistor R5 is grounded, and the other end of resistor R13 is connected to capacitor C2 and grounded.

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