Low-voltage cabinet wired temperature detection system and method thereof
Technical Field
The invention belongs to the field of temperature detection, and particularly discloses a wired temperature detection system and method for a low-voltage cabinet.
Background
The wired temperature monitoring system of the low-voltage cabinet is designed aiming at early prediction of faults of joints of low-voltage switch cabinets of power plants and substations, cable ends and middle heads of low-voltage cables due to insulation aging or poor contact and the like, and can effectively prevent cable fire.
Two temperature measuring systems are used in a low-voltage system, one is designed aiming at the development of a high-voltage system and is directly used for a wireless temperature measuring system for measuring the temperature in a low-voltage cabinet, and a temperature measuring probe of the wireless temperature measuring system is an active watchband probe or a self-powered passive watchband probe using a battery; the other type is a wired temperature on-line monitoring device designed for the low-voltage cabinet, cannot be used for centralized display or is used as a centralized display background by using an industrial personal computer, and has high overall cost, complex debugging and difficult maintenance.
The prior art mainly has the following problems: firstly, the temperature detecting probe needs to be powered by a battery, so that the temperature detecting probe cannot be used for a long time; then, when the system has no current due to the use of the self-powered temperature measuring watchband, temperature data cannot be acquired; then, the temperature data of the product in the prior art is difficult to display in a centralized manner and the temperature data is collected; finally, in the prior art, the temperature data updating period is too long, and the data cannot reflect the real-time temperature value.
Therefore, a novel wired temperature detection system and a detection method for a low-voltage cabinet are urgently needed to solve the problems.
Disclosure of Invention
The invention discloses a wired temperature detection system of a low-voltage cabinet,
the detection system comprises one or more temperature measurement terminals and a display main control unit;
the temperature measuring terminal is used for measuring the temperature of the end to be measured;
the display main control unit is used for receiving data of the plurality of temperature measuring terminals, processing the data and displaying the processed data;
the temperature measuring terminal is connected with the display main control unit through a bus to carry out information interaction.
Furthermore, the temperature measuring terminal comprises a plurality of temperature measuring probes;
and the plurality of temperature measuring probes are connected to the display main control unit through a bus.
Furthermore, the temperature measuring probe is an NTC thermistor packaged by epoxy resin and is connected with the bus through a high-temperature lead.
Further, the display main control unit comprises a display and a data sampler;
the data acquisition sample device acquires and processes the data sent by the temperature measurement terminal, and the display is used for displaying the processed data.
Furthermore, the data acquisition unit comprises a first port, an isolation chip, a CPU chip, an RS232 chip and a second port;
the first port is connected with one end of the bus, and the first port, the isolation chip, the CPU chip, the RS232 chip and the third communication interface are sequentially connected;
the CPU chip receives the data of the temperature measuring terminal and processes the data;
the isolation chip is a driving chip of the first port and is used for electrically isolating the bus from the data acquisition unit;
the RS23 chip is a driving chip of a second port;
the second port is connected with the display.
The invention also discloses a detection method of the low-voltage cabinet wired temperature detection system, which comprises the following steps:
s1: and a temperature probe of the temperature measurement terminal is used for measuring the object to be measured and is connected with the display main control unit through a 485 bus.
S2: and processing the data sent by the temperature measuring terminal by using the display main control unit, and transmitting an interaction result to a display for displaying.
Further, in step S2, the step of processing, by the display main control unit, the data sent by the temperature measurement terminal includes:
s21: the CPU chip sends a state calling message to the 485 chip;
s22: the 485 chip sends a state reply message to the CPU chip;
s23: sequencing the lengths of the data lengths according to at least more priorities, and sending a data calling message to the temperature measuring terminal by the CPU chip according to the sequencing sequence;
s24: the called temperature measurement terminal sends a data message, wherein the data message comprises change temperature data;
s25: and updating the temperature according to the data message sent by the temperature measuring terminal by the CPU information.
Furthermore, the data length determination method includes that a plurality of temperature measurement probes are used for simultaneously acquiring the temperature of the object to be measured, and when the acquired temperature value is different from that acquired at the previous moment, the data length +1 needs to be uploaded at the moment. When n temperature values are all sent to change, the length of the uploaded data + n is needed.
Further, in step S23, when the data length is 0, the CPU chip does not send a data call message to the temperature measurement terminal.
Furthermore, when a plurality of temperature measuring terminals are arranged, the temperature measuring terminals are uniformly distributed on the 485 bus.
The invention has the beneficial effects that:
1) the temperature measuring terminal and the display unit are connected through the bus, information interaction is carried out, and the problem that detection time is limited when a battery is used can be avoided.
2) The NTC thermistor packaged by the sampling epoxy resin has the advantages of faster system response, higher performance, higher temperature measurement precision and longer service life.
3) The temperature data updating period can be greatly reduced, the real-time temperature value is reflected, and the temperature can be displayed in real time.
4) Although a program is seemingly added to the state calling message sent first, the state reply message is only composed of 5 characters, and the temperature measurement terminal with unchanged temperature can be identified, so that the terminal does not need to send a data message, the data updating time is greatly saved, and the data updating speed is accelerated.
Drawings
FIG. 1 is a diagram illustrating a connection between a temperature measuring terminal and a display main control unit according to an embodiment of the present invention;
FIG. 2 is a diagram showing an internal structure of a data sampler in the embodiment of the present invention;
fig. 3 shows a flowchart of a low-voltage cabinet wired temperature detection method in an embodiment of the invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention discloses a wired temperature detection system of a low-voltage cabinet, which comprises one or more temperature measurement terminals and a display main control unit, wherein the temperature measurement terminals are connected with the display main control unit through a bus to perform information interaction. Furthermore, the display main control unit can be connected with a plurality of buses to perform information interaction. Illustratively, the bus is a 485 bus.
Specifically, the temperature measurement terminals are used for measuring the temperature of the end to be measured, and each temperature measurement terminal measures 1 end to be measured. The temperature measurement terminal comprises a plurality of temperature measurement probes which are uniformly distributed around the end to be measured, so that the temperature information of the end to be measured can be more comprehensively collected. And the plurality of temperature measuring probes are all connected into the display main control unit through a bus.
Furthermore, the temperature measuring probe is an NTC thermistor packaged by epoxy resin and is connected with the bus through a high-temperature lead. The NTC thermistor packaged by the epoxy resin has the characteristics of quick response, stable performance, high temperature measurement precision, long service life and the like, and the situation that a bus to be measured can be used only by using a battery-powered or passive self-power-taking temperature measurement probe when the bus to be measured has working current is avoided by using high-temperature wires for connection, so that the battery does not need to be replaced periodically, the requirement on whether the system bus has the working current is avoided, and the temperature can be normally acquired under any condition.
The display main control unit comprises a display and a data collector, and the data collector collects and processes the data sent by the temperature measuring terminal and then sends the data to the display. The display is used for displaying the processed data and operating the operation of the whole system.
Furthermore, the data acquisition unit comprises a first port, an isolation chip, a CPU chip, an RS232 chip and a second port, wherein the first port is connected with one end of the bus, and the first port, the isolation chip, the CPU chip, the RS232 chip and the second port are sequentially connected;
the CPU chip receives the data of the temperature measuring terminal and processes the data; the isolation chip is used for electrically isolating the temperature measuring terminal from the CPU chip and is used as a driving chip of the first port; the RS23 chip is used as a driving chip of a second port, and the second port is connected with a display.
Illustratively, a plurality of temperature measuring terminals are connected with the display main control unit through a 485 bus to carry out bidirectional communication. If the number of the temperature measuring terminals is too many, a plurality of 485 buses can be adopted to be connected with the display main control unit, and the temperature measuring terminals are averagely grouped according to the number of the 485 buses, so that the utilization rate of the 485 buses can be improved to the greatest extent and the stability of the system can be improved by averagely grouping. Each temperature measurement terminal comprises 3 temperature measurement probes, wherein the 3 temperature measurement probes are distributed around the object to be measured and are connected with a 485 lead through a high-temperature lead. One end of the 485 conducting wire is connected with the temperature measuring probe, the other end of the 485 conducting wire is connected with the first port, and particularly, the first port is a 485 port. Therefore, the bidirectional communication between the temperature measuring terminal and the data acquisition unit is realized. Specifically, the data collector comprises a first port, a 485 chip, a CPU chip, an RS232 chip and a second port. Preferably, the first port is a 485 interface, the second port is a 232 interface, and the CPU chip is a 32-bit CPU chip. The temperature measurement terminal carries out two-way communication with the 485 chip through the 485 interface, and further, the 485 chip has an isolation function. The 485 chip is connected with the CPU chip to carry out information interaction and realize temperature detection. The CPU chip is connected with the RS232 chip and outputs the temperature detection result to the display through the 232 interface. Specifically, the number of the buses corresponds to the number of the 485 chips, and the plurality of 485 chips are communicated with 1 CPU chip.
Based on the low-voltage wired temperature detection system, the invention also discloses a low-voltage cabinet wired temperature detection method, which comprises the following steps:
s1: and a temperature probe of the temperature measurement terminal is used for measuring the object to be measured and is connected with the display main control unit through a 485 bus.
S2: and processing the data sent by the temperature measuring terminal by using the display main control unit, and transmitting an interaction result to a display for displaying.
Specifically, in step S2, the step of processing the data sent by the temperature measurement terminal by the display main control unit includes:
s21: and the CPU chip sends a state calling message to the 485 chip.
Specifically, the call message includes a temperature measurement terminal code, a specially agreed state call function code, a CRC check high order bit, and a CRC check low order bit.
S22: and the 485 chip sends a state reply message to the CPU chip.
The reply message occupies 5 characters, wherein one character is a temperature measuring terminal position code, one character is a specially appointed state calling function code, one character is a CRC high order, one character is a CRC low order, and one character is the data length which needs to be uploaded by the temperature measuring terminal. The whole reply message only occupies 5 characters, the data volume is small, and the time consumption for sending the message is short.
Illustratively, the method for determining the length of the data to be uploaded is as follows: carry out temperature acquisition with a plurality of temperature probe to the determinand simultaneously, when the temperature value of gathering is different with the collection at last moment, show that the temperature of this point has changed, need upload to show the main control unit, the data length +1 that needs to upload this moment. When n temperature values are all sent to change, the length of the uploaded data + n is needed.
S23: and sequencing the lengths of the data lengths according to at least more priorities, and sending a data calling message to the temperature measuring terminal by the CPU chip according to the sequencing sequence.
Further, when the data length is 0, the CPU chip does not send a data call message to the temperature measurement terminal.
S24: and the called temperature measuring terminal sends a data message, wherein the data message comprises the data of the changed temperature.
S25: and updating the document by the CPU information according to the data message sent by the temperature measuring terminal.
For example, 20 groups of objects to be measured are subjected to temperature detection, 20 temperature measurement terminals are used, and N temperature measurement terminals are equally divided into K groups
Although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.