Dynamometer with insulation resistance detection function

Abstract

The utility model provides a dynamometer with an insulation resistance detection function, and relates to the technical field of detection. The dynamometer comprises a resistance strain type force transducer, a four-core shielding cable and a secondary instrument, the secondary instrument comprises an insulation resistor and bridge arm resistor detection module, a signal processing module and a line switcher, and the detection module and the signal processing module are respectively connected with the switcher; the output end of the sensor is connected with the line switcher through a connecting cable; the line switcher is used for connecting the sensor with the detection module and disconnecting the sensor from the signal processing module when the insulation resistance and the bridge arm resistance are detected; when force value detection is carried out, the sensor is disconnected from the detection module, and the sensor is connected with the signal processing module. The dynamometer not only has a force value detection function of a standard dynamometer, but also can detect an insulation resistance value and a bridge arm resistance value of the sensor on line, so that the reliability of the dynamometer is improved, a cable does not need to be disassembled and connected, and the dynamometer is convenient to use.

Description

Technical Field

[0001] This utility model relates to the field of testing technology, specifically to a force measuring instrument with insulation resistance testing function. Background Technology

[0002] A resistance strain gauge force gauge consists of two parts: a resistance strain gauge force sensor and a secondary instrument. The sensor uses a Wheatstone bridge composed of resistance strain gauges to measure the force value. The sensor and the secondary instrument are connected via a shielded cable. In force measurement applications in the metallurgical industry, the sensor operates in harsh environments with high load, high temperature, high humidity, and high oil content. This can easily cause cable damage and a decrease in insulation resistance, leading to inaccurate force measurement data and reduced reliability of the force gauge. Utility Model Content

[0003] The purpose of this invention is to address the shortcomings of the prior art by providing a force measuring instrument with insulation resistance detection function, thereby solving the problem of low reliability of the force measuring instrument.

[0004] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0005] This invention provides a force measuring instrument with insulation resistance detection function. The force measuring instrument includes: a resistance strain gauge force sensor, a four-core shielded cable, and a secondary instrument.

[0006] The secondary instrument includes an insulation resistance and bridge arm resistance detection module, a signal processing module, and a line switcher. The insulation resistance and bridge arm resistance detection module and the signal processing module are respectively connected to the line switcher.

[0007] The output of the resistance strain gauge force sensor is connected to the line switch via a four-core shielded cable.

[0008] The line switch is used to: connect the strain gauge force sensor to the insulation resistance and bridge arm resistance detection module and disconnect the strain gauge force sensor from the signal processing module when performing insulation resistance and bridge arm resistance detection; and disconnect the strain gauge force sensor from the insulation resistance and bridge arm resistance detection module and connect the strain gauge force sensor to the signal processing module when performing force value detection.

[0009] Optionally, the line switcher is a relay, and line switching is achieved by contacts.

[0010] Optionally, the insulation resistance and bridge arm resistance detection module includes an insulation resistance detection unit and a bridge arm resistance detection unit. The bridge arm resistance detection unit includes a first detection port and a first operational amplifier, and the insulation resistance detection unit includes a second detection port and a second operational amplifier. The first detection port and the second detection port are respectively connected to the line switcher.

[0011] Optionally, the bridge arm resistance detection unit is specifically used for: when performing bridge arm resistance detection, the first detection port of the bridge arm resistance detection unit is switched through relay contacts. First, the excitation + and excitation - terminals of the excitation bridge arm of the resistance strain gauge force sensor are connected to the resistance detection. Then, the output + and output - terminals of the signal bridge arm of the resistance strain gauge force sensor are connected to the resistance detection. The bridge arm resistance is determined by the signal output by the first operational amplifier. Here, the detection resistor is a constant current 3.67mA, and the detection range is 100Ω to 3kΩ. If the detected bridge arm resistance is in the range of 200Ω to 2kΩ, the bridge arm resistance of the resistance strain gauge force sensor is determined to be normal.

[0012] Optionally, the insulation resistance detection unit is specifically used for: when performing insulation resistance detection, the second detection port of the insulation resistance detection unit is switched through relay contacts, connecting one end of the second detection port to the shielding layer wire or grounding wire of the four-core shielded cable, and connecting the other end of the second detection port to any arm of the resistance strain gauge force sensor. The insulation resistance is determined by the signal output by the second operational amplifier. The insulation resistance detection voltage is DC 50V, and the detection range is 1MΩ to 50MΩ. If the detected insulation resistance value is greater than 30MΩ, the insulation resistance of the resistance strain gauge force sensor is determined to be normal.

[0013] Optionally, the insulation resistance and bridge arm resistance detection functions can be activated via the panel operation of the secondary instrument, and the detection data can be displayed on the display of the secondary instrument.

[0014] The beneficial effects of this utility model include:

[0015] This utility model provides a force measuring instrument with insulation resistance detection function, comprising: a resistance strain gauge force sensor, a four-core shielded cable, and a secondary instrument. The secondary instrument includes an insulation resistance and bridge arm resistance detection module, a signal processing module, and a line switcher. The insulation resistance and bridge arm resistance detection module and the signal processing module are respectively connected to the line switcher. The output terminal of the resistance strain gauge force sensor is connected to the line switcher via the four-core shielded cable. The line switcher is used to: connect the resistance strain gauge force sensor to the insulation resistance and bridge arm resistance detection module and disconnect the resistance strain gauge force sensor from the signal processing module when performing insulation resistance and bridge arm resistance detection; and disconnect the resistance strain gauge force sensor from the insulation resistance and bridge arm resistance detection module and connect the resistance strain gauge force sensor to the signal processing module when performing force value detection. In addition to the conventional force value detection function of a standard force measuring instrument, this force measuring instrument can also detect the insulation resistance and bridge arm resistance values ​​of the force sensor online, improving the reliability of the force measuring instrument. Furthermore, it eliminates the need for cable disconnection, making it convenient to use. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model, 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 some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This diagram shows a structural block diagram of a force measuring instrument with insulation resistance detection function provided in an embodiment of the present invention;

[0018] Figure 2 This invention provides a schematic diagram of the process of using a force measuring instrument to test insulation resistance according to an embodiment of the present invention.

[0019] Figure 3 A schematic diagram of the bridge arm resistance detection unit provided in an embodiment of the present invention is shown;

[0020] Figure 4 A schematic diagram of the insulation resistance detection unit provided in an embodiment of this utility model is shown. Detailed Implementation

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0022] A resistance strain gauge force gauge consists of two parts: a resistance strain gauge force sensor and a secondary instrument. The sensor uses a Wheatstone bridge composed of resistance strain gauges to measure the force value. The sensor and the secondary instrument are connected via a shielded cable. In force measurement applications in the metallurgical industry, the sensor operates in harsh environments with high load, high temperature, high humidity, and high oil content, which can easily cause cable damage and a decrease in insulation resistance, leading to inaccurate force gauge measurements and reduced reliability. Therefore, a novel force gauge with insulation resistance detection function is needed.

[0023] Figure 1 A structural block diagram of a force measuring instrument with insulation resistance detection function provided in an embodiment of this utility model is shown.

[0024] like Figure 1 As shown, the force measuring instrument with insulation resistance detection function provided by this utility model includes: a resistance strain gauge force sensor, a four-core shielded cable, and a secondary instrument.

[0025] The secondary instrument includes an insulation resistance and bridge arm resistance detection module, a signal processing module, and a line switcher. The insulation resistance and bridge arm resistance detection module and the signal processing module are respectively connected to the line switcher.

[0026] The output of the resistance strain gauge force sensor is connected to the line switch via a four-core shielded cable.

[0027] The line switch is used to: connect the strain gauge force sensor to the insulation resistance and bridge arm resistance detection module and disconnect the strain gauge force sensor from the signal processing module when performing insulation resistance and bridge arm resistance detection; and disconnect the strain gauge force sensor from the insulation resistance and bridge arm resistance detection module and connect the strain gauge force sensor to the signal processing module when performing force value detection.

[0028] The signal processing module in the secondary instrument is used for routine force detection, while the insulation resistance and bridge arm resistance detection modules are used to measure the insulation resistance and bridge arm resistance of the resistance strain gauge force sensor.

[0029] Optionally, the line switcher is a relay, and line switching is achieved by contacts. The insulation resistance and bridge arm resistance detection module includes an insulation resistance detection unit and a bridge arm resistance detection unit. The bridge arm resistance detection unit includes a first detection port and a first operational amplifier, and the insulation resistance detection unit includes a second detection port and a second operational amplifier. The first detection port and the second detection port are respectively connected to the line switcher, and the corresponding ports of the sensor bridge arms are respectively connected to the detection.

[0030] For measuring the insulation resistance of a sensor, unlike conventional resistance testing, a larger external voltage is required. This invention uses a DC 50V voltage for detection. However, directly applying DC 50V to the sensor's bridge arm would inevitably damage the secondary instrument's signal processing module. Therefore, a line switching switch is needed. When performing insulation resistance and bridge arm resistance testing, the sensor's circuitry must be disconnected from the secondary instrument's signal processing module. Conversely, when performing force value testing, the sensor's circuitry must be disconnected from the secondary instrument's insulation resistance and bridge arm resistance detection modules. The insulation resistance testing process is as follows: Figure 2 As shown.

[0031] Figure 3 A schematic diagram of the bridge arm resistance detection unit provided in an embodiment of this utility model is shown. Figure 3In this diagram, J1 represents the first detection port, and U3 represents the first operational amplifier. U2 represents a voltage regulator, which keeps the "+" input of the first operational amplifier U3 constant at 2.5VDC. The bridge arm resistance detection unit is specifically used for: during bridge arm resistance detection, the first detection port of the bridge arm resistance detection unit switches via relay contacts. First, the excitation + and excitation - terminals of the excitation bridge arm of the resistance strain gauge force sensor are connected to the resistance detection. Then, the output + and output - terminals of the signal bridge arm of the resistance strain gauge force sensor are connected to the resistance detection. The bridge arm resistance is determined by the signal output from the first operational amplifier. Here, a constant current 3.67mA detection resistor is used, with a detection range of 100Ω to 3kΩ. If the detected bridge arm resistance is within the range of 200Ω to 2kΩ, the bridge arm resistance of the resistance strain gauge force sensor is considered normal.

[0032] Figure 4 A schematic diagram of the insulation resistance detection unit provided in an embodiment of this utility model is shown. Figure 4 In the diagram, J2 represents the second detection port, and U1 represents the second operational amplifier. D1 represents a voltage regulator, clamping the sampling power supply to 10V DC to prevent damage to the second operational amplifier in case of excessively low insulation resistance at J2. Specifically, the insulation resistance detection unit is used as follows: During insulation resistance testing, the second detection port of the insulation resistance detection unit is switched via relay contacts. One end of the second detection port is connected to the shielding layer of a four-core shielded cable or the grounding wire (because the housing of the resistance strain gauge force sensor is connected to the grounding wire), and the other end is connected to any arm of the resistance strain gauge force sensor. The insulation resistance is determined by the signal output from the second operational amplifier. The insulation resistance detection voltage is DC 50V, and the detection range is 1MΩ to 50MΩ. If the detected insulation resistance value is greater than 30MΩ, the insulation resistance of the resistance strain gauge force sensor is considered normal.

[0033] Optionally, the insulation resistance and bridge arm resistance detection functions can be activated via the panel operation of the secondary instrument, and the detection data can be displayed on the display of the secondary instrument.

[0034] In summary, in addition to the standard force measurement function of a force gauge, this force gauge can also detect the insulation resistance and bridge arm resistance of the force sensor online, improving the reliability of the force gauge. Furthermore, it is convenient to use as it does not require disconnection of cables.

[0035] The above embodiments are only for illustrating the technical concept and features of this utility model. Their purpose is to enable those skilled in the art to understand the content of this utility model and implement it. They should not be used to limit the protection scope of this utility model. All equivalent changes or modifications made in accordance with the spirit and essence of this utility model should be covered within the protection scope of this utility model.

Claims

1. A force measuring instrument with insulation resistance detection function, characterized in that, The force measuring instrument includes: a resistance strain gauge force sensor, a four-core shielded cable, and secondary instruments. The secondary instrument includes an insulation resistance and bridge arm resistance detection module, a signal processing module, and a line switcher. The insulation resistance and bridge arm resistance detection module and the signal processing module are respectively connected to the line switcher. The output of the resistance strain gauge force sensor is connected to the line switch via the four-core shielded cable. The line switch is used to: connect the strain gauge force sensor to the insulation resistance and bridge arm resistance detection module and disconnect the strain gauge force sensor from the signal processing module when performing insulation resistance and bridge arm resistance detection; and disconnect the strain gauge force sensor from the insulation resistance and bridge arm resistance detection module and connect the strain gauge force sensor to the signal processing module when performing force value detection.

2. The force measuring instrument with insulation resistance detection function according to claim 1, characterized in that, The line switcher is a relay, and line switching is achieved through contacts.

3. The force measuring instrument with insulation resistance detection function according to claim 2, characterized in that, The insulation resistance and bridge arm resistance detection module includes an insulation resistance detection unit and a bridge arm resistance detection unit. The bridge arm resistance detection unit includes a first detection port and a first operational amplifier. The insulation resistance detection unit includes a second detection port and a second operational amplifier. The first detection port and the second detection port are respectively connected to the line switch.

4. The force measuring instrument with insulation resistance detection function according to claim 3, characterized in that, The bridge arm resistance detection unit is specifically used for: when performing bridge arm resistance detection, the first detection port of the bridge arm resistance detection unit is switched through relay contacts. First, the excitation + and excitation - ends of the excitation bridge arm of the resistance strain gauge force sensor are connected to the resistance detection. Then, the output + and output - ends of the signal bridge arm of the resistance strain gauge force sensor are connected to the resistance detection. The bridge arm resistance is determined by the signal output by the first operational amplifier. Here, the detection resistor is a constant current 3.67mA, and the detection range is 100Ω to 3kΩ. If the detected bridge arm resistance is in the range of 200Ω to 2kΩ, then the bridge arm resistance of the resistance strain gauge force sensor is determined to be normal.

5. The force measuring instrument with insulation resistance detection function according to claim 3, characterized in that, The insulation resistance detection unit is specifically used for: when performing insulation resistance detection, the second detection port of the insulation resistance detection unit is switched through relay contacts, connecting one end of the second detection port to the shielding layer wire or grounding wire of the four-core shielded cable, and connecting the other end of the second detection port to any bridge arm of the resistance strain gauge force sensor. The insulation resistance is determined by the signal output by the second operational amplifier. The insulation resistance detection voltage is DC 50V, and the detection range is 1MΩ to 50MΩ. If the detected insulation resistance value is greater than 30MΩ, the insulation resistance of the resistance strain gauge force sensor is determined to be normal.

6. The force measuring instrument with insulation resistance detection function according to claim 1, characterized in that, The insulation resistance and bridge arm resistance detection functions are activated via the panel of the secondary instrument, and the detection data is displayed on the display of the secondary instrument.

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