CN115902410A - Automatic measuring device for direct current resistance of auxiliary loop switch contact - Google Patents
Automatic measuring device for direct current resistance of auxiliary loop switch contact Download PDFInfo
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- CN115902410A CN115902410A CN202210237519.6A CN202210237519A CN115902410A CN 115902410 A CN115902410 A CN 115902410A CN 202210237519 A CN202210237519 A CN 202210237519A CN 115902410 A CN115902410 A CN 115902410A
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Abstract
The invention discloses an automatic measuring device for the direct current resistance of an auxiliary loop switch contact, which comprises: an auxiliary loop: the device comprises a direct current power supply, a current acquisition module, a voltage acquisition module and a rheostat; the auxiliary loop is connected with the PLC control module through the AD module; the current acquisition module and the voltage acquisition module respectively acquire a current signal value and a voltage signal value of the auxiliary loop and send the current signal value and the voltage signal value to the PLC control module through the AD module; calculating the direct current resistance value of the rheostat through the PLC control module; the switching value input module is used for converting the state signal of the position of the sliding contact of the rheostat into a digital signal and then sending the digital signal to the PLC control module; the PLC control module converts a control signal of the position of the sliding contact into a control electric signal through the switching value output module and then sends the control electric signal to the control loop; the control loop comprises a step controller and a step motor and is used for adjusting the position of the sliding contact of the rheostat.
Description
Technical Field
The invention relates to the technical field of electrical tests, in particular to an automatic measuring device for direct current resistance of an auxiliary circuit switch contact.
Background
The auxiliary and control loops of medium-high voltage switchgear are generally implemented by mechanical switches to signal indication of the switching state or to control the switching off of the power supply, so the direct current resistance of the auxiliary switch contacts directly affects the performance of the medium-high voltage switchgear. The traditional test method adopts manual measurement, the numerical value is inaccurate, and the real state of the auxiliary loop switch contact cannot be correctly reflected.
Therefore, a technique is needed to achieve automatic measurement of the dc resistance of the auxiliary circuit switch contacts.
Disclosure of Invention
The technical scheme of the invention provides an automatic measuring device for the direct current resistance of an auxiliary loop switch contact, which aims to solve the problem of how to automatically measure the direct current resistance of the auxiliary loop switch contact.
In order to solve the above problems, the present invention provides an automatic measuring device for the direct current resistance of an auxiliary loop switch contact, comprising:
an auxiliary circuit, the auxiliary circuit comprising: the device comprises a direct current power supply, a current acquisition module, a voltage acquisition module and a rheostat;
the auxiliary loop is connected with the PLC control module through the AD module;
the current acquisition module and the voltage acquisition module respectively acquire a current signal value and a voltage signal value of the auxiliary loop and send the current signal value and the voltage signal value to the PLC control module through the AD module; calculating the direct current resistance value of the rheostat through the PLC control module;
the switching value input module is used for converting the state signal of the position of the sliding contact of the rheostat into a digital signal and then sending the digital signal to the PLC control module;
the PLC control module converts a control signal of the position of the sliding contact into a control electric signal through the switching value output module and then sends the control electric signal to the control loop;
the control loop comprises a stepping controller and a stepping motor, the stepping controller sends a stepping control instruction to the stepping motor based on the received control electric signal, and the stepping motor adjusts the position of the sliding contact of the rheostat based on the stepping control instruction.
The touch screen is connected with the PLC control module and used for providing a man-machine interface, displaying a current signal value, a voltage signal value, measuring a direct current resistance value and a sliding contact position.
Preferably, the step motor adjusts the position of the sliding contact of the rheostat based on the step control instruction, and the step motor comprises:
and the stepping motor converts the received stepping control instruction into displacement of a sliding contact of the rheostat, adjusts the position of the sliding contact of the rheostat on the basis of the displacement and changes the output direct current resistance value of the rheostat.
Preferably, the switching value input module is further configured to: and when the state signal of the position of the sliding contact of the rheostat is the left limit or the right limit of the position of the sliding contact, generating a state limit signal, and controlling the auxiliary circuit to be powered off by the PLC control module based on the state limit signal.
Preferably, the PLC control module is Siemens SR20.
Preferably, the stepping motor adjusts the position of the sliding contact of the rheostat through a screw rod.
Preferably, the AD module is 12 bit AD precision.
Preferably, the voltage of the direct current power supply is 5V.
Preferably, the signal acquisition range of the current acquisition module is as follows: 0-20mA, 10Hz sampling frequency and 12 AD sampling precision;
the voltage acquisition module acquires signal ranges as follows: 0-5V, 10Hz sampling frequency and 12 bits AD sampling precision.
Preferably, when the current signal value acquired by the current acquisition module is greater than or less than a preset current threshold value, the control signal of the position of the sliding contact is converted into a control electrical signal through the switching value output module by the PLC control module and then sent to the control loop, and the direct current resistance value of the rheostat is adjusted until the current signal value is equal to the preset current threshold value.
Preferably, the current threshold is 10mA.
The technical scheme of the invention provides an automatic measuring device for the direct current resistance of an auxiliary loop switch contact, which comprises: an auxiliary circuit, the auxiliary circuit comprising: the device comprises a direct current power supply, a current acquisition module, a voltage acquisition module and a rheostat; the auxiliary loop is connected with the PLC control module through the AD module; the current acquisition module and the voltage acquisition module respectively acquire a current signal value and a voltage signal value of the auxiliary loop and send the current signal value and the voltage signal value to the PLC control module through the AD module; calculating the direct current resistance value of the rheostat through the PLC control module; the switching value input module is used for converting the state signal of the position of the sliding contact of the rheostat into a digital signal and then sending the digital signal to the PLC control module; the PLC control module converts a control signal of the position of the sliding contact into a control electric signal through the switching value output module and then sends the control electric signal to the control loop; the control loop comprises a stepping controller and a stepping motor, the stepping controller sends a stepping control instruction to the stepping motor based on a received control electric signal, and the stepping motor adjusts the position of the sliding contact of the rheostat based on the stepping control instruction. The technical scheme of the invention designs and researches an automatic measuring device for the DC resistance test of the auxiliary loop switch contact, and verifies the automatic measuring device according to the technical requirement for sharing the standards of DL/T593-2016 high-voltage switch equipment and control equipment.
Drawings
Exemplary embodiments of the invention may be more completely understood in consideration of the following drawings:
fig. 1 is a structural diagram of an automatic measuring device for direct current resistance of an auxiliary loop switch contact according to a preferred embodiment of the invention;
FIG. 2 is a schematic diagram of a resistor and a stepping motor according to a preferred embodiment of the present invention;
FIG. 3 is a schematic diagram of the testing principle according to the preferred embodiment of the present invention;
FIG. 4 is a schematic diagram of the communication function of the AD module according to the preferred embodiment of the present invention;
FIG. 5 is a schematic diagram of voltage current collection according to a preferred embodiment of the present invention; and
fig. 6 is a schematic flow chart of the test operation according to the preferred embodiment of the present invention.
Detailed Description
The exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, however, the present invention may be embodied in many different forms and is not limited to the embodiments described herein, which are provided for complete and complete disclosure of the present invention and to fully convey the scope of the present invention to those skilled in the art. The terms used in the exemplary embodiments shown in the drawings are not intended to limit the present invention. In the drawings, the same units/elements are denoted by the same reference numerals.
Unless otherwise defined, terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Further, it will be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense.
Fig. 1 is a structural diagram of an automatic measuring device for direct current resistance of an auxiliary loop switch contact according to a preferred embodiment of the invention. In the present situation of rapid increase of manpower costs, low-tech staff are increasingly difficult to find. The quality of the personnel and the responsibility affect the final result of the test. The automatic measuring device provided by the invention can well solve the problems.
The invention provides an automatic measuring device for the direct current resistance of an auxiliary loop switch contact, which comprises:
an auxiliary circuit comprising: the device comprises a direct current power supply, a current acquisition module, a voltage acquisition module and a rheostat; preferably, the voltage of the dc power supply is 5V.
The auxiliary loop is connected with the PLC control module through the AD module; preferably, the PLC control module is siemens SR20. Preferably, the AD module is 12 bit AD precision.
The current acquisition module and the voltage acquisition module respectively acquire a current signal value and a voltage signal value of the auxiliary loop and send the current signal value and the voltage signal value to the PLC control module through the AD module; calculating the direct current resistance value of the rheostat through the PLC control module;
preferably, the signal acquisition range of the current acquisition module is as follows: 0-20mA, the sampling frequency is 10Hz, and the sampling precision is 12 bits AD;
the voltage acquisition module acquires signal ranges as follows: 0-5V, 10Hz sampling frequency and 12 bits AD sampling precision.
The switching value input module is used for converting the state signal of the position of the sliding contact of the rheostat into a digital signal and then sending the digital signal to the PLC control module;
preferably, the switching value input module is further configured to: when the state signal of the position of the sliding contact of the rheostat is the left limit or the right limit of the position of the sliding contact, a state limit signal is generated, and the PLC control module controls the auxiliary circuit to be powered off based on the state limit signal.
The PLC control module converts a control signal of the position of the sliding contact into a control electric signal through the switching value output module and then sends the control electric signal to the control loop;
the control loop comprises a stepping controller and a stepping motor, the stepping controller sends a stepping control instruction to the stepping motor based on the received control electric signal, and the stepping motor adjusts the position of the sliding contact of the rheostat based on the stepping control instruction.
Preferably, the step motor adjusts the position of the sliding contact of the rheostat based on the step control instruction, and the step motor comprises:
the stepping motor converts the received stepping control instruction into displacement of the sliding contact of the rheostat, adjusts the position of the sliding contact of the rheostat based on the displacement and changes the output direct current resistance value of the rheostat.
Preferably, the stepping motor adjusts the position of the sliding contact of the rheostat through the screw rod.
Preferably, when the current signal value acquired by the current acquisition module is greater than or less than a preset current threshold value, the control signal of the position of the sliding contact is converted into a control electric signal through the switching value output module by the PLC control module and then is sent to the control loop, and the direct current resistance value of the rheostat is adjusted until the current signal value is equal to the preset current threshold value.
Preferably, the current threshold is 10mA.
And the touch screen is connected with the PLC control module and used for providing a man-machine interface, displaying a current signal value, a voltage signal value, measuring a direct current resistance value and measuring the position of the sliding contact.
As shown in fig. 1, the touch screen of the present invention: the human-computer interaction interface is used for setting test voltage, starting and stopping the test by an operator; history records can be viewed;
PLC: the core unit of the whole system is responsible for processing input signals and touch screen control commands and outputting signals according to logic control;
a step controller: the controller is used for controlling the stepping motor and controls the stepping motor through the switching value output controlled by the PLC;
a stepping motor: the stepping motor is controlled by a stepping control input signal and can quickly respond, is used as an actuating element in an automatic control system, has the characteristics of small electromechanical time constant, high linearity, starting voltage and the like, and can convert a received electric signal into the displacement of a sliding contact of the sliding rheostat so as to change the output resistance;
rheostat: the electric slide rheostat can control the movement of the slide contact through the control of the motor, so as to change the resistance value;
current collection: collecting current signals on the auxiliary contact, and feeding the current signals back to the PLC through the AD module;
voltage acquisition: collecting a voltage signal on the auxiliary contact, and feeding the voltage signal back to the PLC through the AD module;
an AD module: the signal conversion module is used for converting the signals acquired by the voltage and current acquisition module into digital signals and directly uploading the digital signals to the PLC;
a direct-current power supply: the 5V power supply is used for assisting a power supply for the direct current resistance test of the loop;
the switching value input module: converting the signal state of the rheostat sliding contact position into a digital signal and providing the digital signal to the PLC;
a switching value output module: the PLC converts the control command output into an electric signal and outputs the electric signal to an external control loop.
Referring to fig. 1, the measuring device provided by the invention comprises a touch screen, a PLC, a stepping motor, a stepping control, an AD module, a dc power supply, a voltage acquisition, a current acquisition, a rheostat, and a switching value output module. The operation of the apparatus is explained below.
(1) Connection of touch screen and PLC
The touch screen and the PLC are both supplied with power by a 24V power supply; through network fracture interconnect, the following parameters are displayed on the touch screen:
loop voltage
Loop current
Measuring direct current resistance
Limited input condition
(2) Direct current power supply
And providing a direct current test source with an opening voltage of 5V according to the standard.
(3) Voltage acquisition and current acquisition
Brand name: analog quantity acquisition module adopting Altai
Signal input: 0-20mA/0-5V
Sampling frequency: 10Hz
Sampling precision 12 bit AD
(4) Switching value input module
Inputting a signal: the left and right of the slide rheostat and the opening and closing state of the auxiliary switch.
The collection purpose is as follows: if the stepping motor drives the sliding contact to move to the left limit position and the right limit position, the power is automatically cut off, and electronic stalling is prevented.
(5) Principle of experiment
As shown in fig. 3, which is a schematic diagram of the test, the main components include:
voltage collecting meter
Current collecting meter
Electric sliding rheostat
PLC control unit
Network port
Limit switch signal input
Auxiliary contact for test article
(6) The test principle is shown in fig. 3.
When a test is started, a 5V power supply provides test voltage required by a loop, a current collection meter collects test current in the loop, a PLC checks the current through a 485 port, when the current is smaller than or larger than 10mA, the PLC drives a slide rheostat to increase/decrease so that a loop circuit is equal to 10mA, the voltage at the contact of an auxiliary loop is measured, and the required direct current resistance value can be obtained through ohm's law and R = U/I.
(7) Principle of voltage and current collection
Fig. 5 shows the address corresponding to the PLC communication for data acquisition of the AD conversion module.
The input signal is 0-5V or 0-20mA corresponding to 0-65535 of the digital quantity.
Fig. 2 is a schematic structural diagram of a resistor and a stepping motor according to a preferred embodiment of the invention. As shown in fig. 2, 1 is a left limit switch, 2 is a sliding lead screw, 3 is a sliding contact, 4 is a right limit switch, 5 is a stepping motor, 6 is a resistance wire, and 7 is a binding post.
The invention adopts the Modbus RTU block of Siemens to communicate with the AD acquisition module, the AD acquisition module inputs the acquired voltage to the communication interface of PLC through 485, and only 1 AD conversion module is needed, so that only the data of the slave station 1 needs to be set. Since the current path in the wiring is at path 1, the voltage signal is at path 2. The conversion of the analog quantity into a digital quantity 0-65535 is carried out by the procedure shown in fig. 4 in order to obtain the measured voltage value.
The invention provides an automatic measuring device for the direct current resistance of an auxiliary loop switch contact based on an electric slide rheostat, which is characterized by comprising an automatic measuring device body for the direct current resistance of the auxiliary loop switch contact and a detecting device arranged in the automatic measuring device body for the direct current resistance of the auxiliary loop switch contact, wherein the automatic measuring device body for the direct current resistance of the auxiliary loop switch contact is also provided with a touch screen display device and an input device, and the display device and the input device are electrically connected with the detecting device; the detection device comprises a PLC control module, a stepping controller module, a stepping motor module and an AD conversion module. The detection device also comprises a set of variable sliding rheostat controlled based on the stepping motor. The variable sliding rheostat also comprises a left limit and a right limit which provide safety guarantee. The invention relates to an automatic measuring device for the direct current resistance of an auxiliary loop switch contact of an electric slide rheostat, which is characterized in that the detecting device also comprises a control PLC module which selects a Siemens SR20. The invention relates to an automatic measuring device for the direct current resistance of an auxiliary loop switch contact of an electric slide rheostat, wherein the electric slide rheostat is controlled by adopting a screw rod combined with a stepping motor. The invention relates to an automatic measuring device for the direct current resistance of an auxiliary loop switch contact of an electric slide rheostat, wherein an AD conversion module adopts 12-bit AD precision.
The operation flow of testing the dc resistance value of the present invention is shown in fig. 6.
The invention has been described with reference to a few embodiments. However, other embodiments of the invention than the one disclosed above are equally possible within the scope of the invention, as would be apparent to a person skilled in the art from the appended patent claims.
Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a// the [ device, component, etc ]" are to be interpreted openly as at least one instance of a device, component, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.
Claims (10)
1. An automatic measurement device for the direct current resistance of an auxiliary loop switch contact, the device comprising:
an auxiliary circuit, the auxiliary circuit comprising: the device comprises a direct current power supply, a current acquisition module, a voltage acquisition module and a rheostat;
the auxiliary loop is connected with the PLC control module through the AD module;
the current acquisition module and the voltage acquisition module respectively acquire a current signal value and a voltage signal value of the auxiliary loop and send the current signal value and the voltage signal value to the PLC control module through the AD module; calculating the direct current resistance value of the rheostat through the PLC control module;
the switching value input module is used for converting the state signal of the position of the sliding contact of the rheostat into a digital signal and then sending the digital signal to the PLC control module;
the PLC control module converts a control signal of the position of the sliding contact into a control electric signal through the switching value output module and then sends the control electric signal to the control loop;
the control loop comprises a stepping controller and a stepping motor, the stepping controller sends a stepping control instruction to the stepping motor based on the received control electric signal, and the stepping motor adjusts the position of the sliding contact of the rheostat based on the stepping control instruction.
2. The apparatus of claim 1, the stepper motor adjusting a slider position of the varistor based on the step control command, comprising:
and the stepping motor converts the received stepping control instruction into displacement of a sliding contact of the rheostat, adjusts the position of the sliding contact of the rheostat based on the displacement and changes the output direct current resistance value of the rheostat.
3. The apparatus of claim 1, the switching value input module, further configured to: and when the state signal of the position of the sliding contact of the rheostat is the left limit or the right limit of the position of the sliding contact, generating a state limit signal, and controlling the auxiliary circuit to be powered off by the PLC control module based on the state limit signal.
4. The apparatus of claim 1, said PLC control module being siemens SR20.
5. The device of claim 1, wherein the stepper motor adjusts the position of the varistor slider via a lead screw.
6. The device of claim 1, the AD module is 12-bit AD precision.
7. The apparatus of claim 1, the voltage of the dc power supply being 5V.
8. The device of claim 1, wherein the current collection module collects signal ranges of: 0-20mA, 10Hz sampling frequency and 12 AD sampling precision;
the voltage acquisition module acquires signal ranges as follows: 0-5V, 10Hz sampling frequency and 12 bits AD sampling precision.
9. The device of claim 1, wherein when the current signal value collected by the current collection module is greater than or less than a preset current threshold value, the PLC control module converts the control signal of the position of the sliding contact into a control electrical signal through the switching value output module and sends the control electrical signal to the control loop, and the dc resistance value of the rheostat is adjusted until the current signal value is equal to the preset current threshold value.
10. The apparatus of claim 1, the current threshold being 10mA.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210237519.6A CN115902410A (en) | 2022-03-11 | 2022-03-11 | Automatic measuring device for direct current resistance of auxiliary loop switch contact |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210237519.6A CN115902410A (en) | 2022-03-11 | 2022-03-11 | Automatic measuring device for direct current resistance of auxiliary loop switch contact |
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| Publication Number | Publication Date |
|---|---|
| CN115902410A true CN115902410A (en) | 2023-04-04 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210237519.6A Pending CN115902410A (en) | 2022-03-11 | 2022-03-11 | Automatic measuring device for direct current resistance of auxiliary loop switch contact |
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| CN (1) | CN115902410A (en) |
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- 2022-03-11 CN CN202210237519.6A patent/CN115902410A/en active Pending
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