CN106482870A - Wolfram rhenium heat electric couple examines and determine data collecting system - Google Patents

Abstract

The invention relates to a tungsten-rhenium thermocouple verification data acquisition system, comprising: a master station and a slave station connected through a process field bus, wherein the master station includes a type of master station that interacts with the slave station through the process field bus and can control the The process field bus is set up and communicates with a class II master station. The slave station includes a standard infrared temperature acquisition device and a detected thermocouple potential acquisition device respectively connected to the process field bus. The tungsten-rhenium thermocouple verification data acquisition system of the present invention can be well applied to the high-temperature tungsten-rhenium thermocouple automatic verification system, has the characteristics of high speed, high efficiency, and high degree of automation, and can be carried out within the range of 800 ° C to 2300 ° C Data acquisition and calibration fills the gap in the current industry in the temperature range of 1500°C to 2300°C.

Description

Tungsten rhenium thermocouple verification data acquisition system

technical field

The invention relates to a data acquisition system, in particular to a tungsten-rhenium thermocouple verification data acquisition system based on a process field bus.

Background technique

In various industries such as metallurgy, petroleum, chemical industry, machinery, aerospace and other industries, the measurement of temperature is of great significance. At present, according to different measurement methods, temperature measurement can be roughly divided into two categories, one is contact measurement, and the other is non-contact measurement. For contact measurement, thermocouple is the most used temperature measuring element. Thermocouple is a common temperature measurement element based on the principle of thermoelectric effect, which has been widely used in various industries, especially in some high temperature measurement environments such as metallurgy, aerospace industry, etc. But for the thermocouple itself, according to the national measurement regulations, it needs to be verified regularly after it leaves the factory or has been used for a period of time. At present, the verification work of all thermocouples needs to be carried out in accordance with the content stipulated in the National Metrology Technical Specifications of the People's Republic of China. According to different specifications, the working temperature of thermocouples is 300 ° C ~ 2200 ° C, 20 ° C ~ 2800 ° C ℃ and 0~1500℃, etc., but in the specification for 0~1500℃, only the verification work of the tungsten-rhenium thermocouple in the working range of 0~1500℃ is explained, but there is no correlation for the calibration above 1500℃ In 1988, the Liaoning Provincial Institute of Metrology and Testing Technology was entrusted by the national metrology department to draft the "JJG576-1988 Verification Regulations for Tungsten-Rhenium Thermocouples for Work", which is for the temperature of tungsten-rhenium thermocouples at 0 to 2300 ° C. The verification method was explained accordingly, but it was replaced by the specification "JJF 1176-2007" in 2007. Since then, the verification specification for 1500-2300 ° C has been blank; but the tungsten-rhenium thermocouple is often in this range Therefore, how to calibrate the tungsten-rhenium thermocouple used in this range needs to be solved, and what kind of standard is used to standardize its verification also needs to be studied.

Some domestic research institutes and enterprises have researched on the tungsten-rhenium thermocouple verification system based on the fact that the working environment of the tungsten-rhenium thermocouple is lower than 1500°C. There are basically no researches and reports on the temperature range of 1500°C to 2300°C, especially The tungsten-rhenium thermocouple automatic verification device with high speed, high efficiency, high degree of automation, anti-oxidation function and other characteristics combined with advanced computer, automatic control and other technologies.

PROFIBUS is the abbreviation of the corresponding uppercase letters in Process Field BUS, which is called process field bus. PROFIBUS bus is an international field bus standard for factory automation and process automation. It has been widely used in modern industries, such as manufacturing automation (automobile manufacturing, storage systems, etc.), process automation (petrochemical, paper and textile industries, etc.), power electronics, traffic management, and building automation related to our lives and other industries. Data transfer between devices such as sensors, actuators, and PLCs can be realized by using the PROFIBUS bus standard.

Contents of the invention

The invention provides a tungsten-rhenium thermocouple verification data acquisition system to establish a data acquisition mode for thermocouples in a working environment of 1500°C to 2300°C and fill in the relevant industry gap.

The tungsten-rhenium thermocouple verification data acquisition system of the present invention includes: a master station and a slave station connected by a process field bus (PROFIBUS), wherein the master station includes a type of master station that interacts with the slave station through the process field bus and can The process field bus sets up and communicates with a class II master station, and the slave station includes a standard infrared temperature acquisition device and a detected thermocouple potential acquisition device respectively connected to the process field bus. The first-class master station realizes the functions of controlling the slave station, data exchange, parameter setting, diagnosis, etc. The second-class master station can communicate with the first-class master station, and can configure the process field bus accordingly, parameter initialization, etc. According to the principle of thermocouple temperature measurement, the potential measured when measuring the temperature of the thermocouple is the potential difference between the measuring end and the reference end of the thermocouple. The potential is collected by the detected thermocouple potential collection device, and its structure can be realized by using existing devices. This system adopts the empty gun method to test the thermocouple, so the standard infrared temperature acquisition device is used to collect the data of the thermocouple. The temperature measurement range of the standard infrared temperature acquisition device is 250°C to 3000°C, which can meet the required data acquisition in the range of 2300°C.

Specifically, the above-mentioned type of master station is a PC or a PLC device. The role of the first-class master station is not only the central controller, but there can be multiple first-class master stations in one system to control multiple slave stations.

Specifically, the Class II master station includes a control unit connected to the process field bus through a network communication card. The second-class master station has the functions of setting slave station address, configuration, system monitoring, etc., and can include devices such as programmers, configuration devices and/or PCs.

Optionally, the control unit is also connected with a printing device for printing and archiving corresponding data.

On this basis, the slave station also includes a verification furnace temperature control device connected to the process field bus. The temperature change rate of the verification furnace after constant temperature should be <= 2°C/min. The verification furnace temperature control device is used to control the verification furnace temperature. Furnace temperature, so that the deviation between the verification temperature and the set temperature of the verification furnace is ±5°C.

Further, an alarm system is provided in the furnace temperature control device of the verification furnace, which will give an alarm prompt when the temperature control is abnormal. The alarm system can adopt existing conventional structural methods, such as sound alarm or sound and light alarm.

The tungsten-rhenium thermocouple verification data acquisition system of the present invention can be well applied to the high-temperature tungsten-rhenium thermocouple automatic verification system, has the characteristics of high speed, high efficiency, and high degree of automation, and can be carried out within the range of 800 ° C to 2300 ° C Data acquisition and calibration fills the gap in the current industry in the temperature range of 1500°C to 2300°C.

The above-mentioned content of the present invention will be further described in detail below in conjunction with the specific implementation manners of the examples. However, this should not be construed as limiting the scope of the above-mentioned subject matter of the present invention to the following examples. Without departing from the above-mentioned technical idea of the present invention, various replacements or changes made according to common technical knowledge and customary means in this field shall be included in the scope of the present invention.

Description of drawings

Fig. 1 is a block diagram of a data acquisition system for tungsten-rhenium thermocouple verification of the present invention.

detailed description

As shown in Figure 1, the tungsten-rhenium thermocouple verification data acquisition system of the present invention is connected with a master station and a slave station through a process field bus. The master station includes a first-class master station and a second-class master station, and the first-class master station is a PLC device, which interacts with the slave station through a process field bus. The role of the first-class master station is not only the central controller, but there can be multiple first-class master stations in one system to control multiple slave stations. The second-class master station includes a control unit connected with the process field bus through a network communication card, and a printing device connected with the control unit. The second-class master station has the functions of setting slave station address, configuration, system monitoring, etc., and can include devices such as programmers, configuration devices and/or PCs. The second-class master station can set up the process field bus and communicate with the first-class master station.

The slave station includes a standard infrared temperature acquisition device and a detected thermocouple potential acquisition device respectively connected to the process field bus, and a verification furnace temperature control device connected to the process field bus. There is an alarm system in the middle, which will give an alarm prompt when the temperature control is abnormal. The alarm system can adopt existing conventional structural methods, such as sound alarm or sound and light alarm.

When choosing the equipment, the master station of the first category chooses Siemens S7-300 series PLC equipment. Its CPU model is 319-3DP, equipped with MPI (message transfer application program interface), RS485 and other interfaces, can build a data acquisition system based on process field bus (PROFIBUS), and the maximum transmission speed is 12M/s.

The control unit of the second-class master station adopts Advantech’s embedded box-type ARK-5260 industrial computer. The structure of the ARK-5260 industrial computer is very compact, and it adopts a sealed structure that runs without fans. It supports 1.66GHz Intel CPU and has 5 USB2.0 ports. , Support 4 RS-232/422/485 interfaces with automatic flow control, built-in 1 PCI-e and 2 PCI expansion slots, PC expansion board adopts rubber shock resistance. By installing corresponding software on the industrial machine, such as configuration software such as WINCC, FIX, and force control, as well as programming interface software STEP7, etc., the hardware configuration and control of the process field bus can be realized.

The network communication card is the CP5613 network card of Siemens. The CP5613 network has a process field bus network interface card based on the PCI bus, which is mainly used to connect the industrial computer to the process field bus. By installing the CP5613 network card into the PCI expansion slot of the ARK-5260 industrial computer, the industrial computer can be connected to the process field bus and used as the master station.

The standard infrared temperature acquisition device in the slave station is the Raytek Marathon FA series infrared thermometer produced by the American Raytek (Raytek) company. The infrared thermometer has an RS485 serial communication interface and can be connected to the process field bus.

In the thermocouple potential acquisition device under test, Keithley's 2010 seven-and-a-half-digit multimeter is used to measure the thermocouple thermoelectric potential. However, because the digital multimeter only has RS232 and GBIP communication interfaces, it cannot directly communicate with the process field bus. Therefore, the connection between the digital multimeter and the process field bus must be realized through the corresponding communication interface. That is to use single-chip microcomputer + protocol control chip to realize the reading of the measurement results of the digital multimeter and transmit them to the process field bus. Among them, the AT89S52 single-chip microcomputer is selected, which has 8-bit CPU and in-system programmable Flash on a single chip, so that the AT89S52 single-chip microcomputer can provide highly flexible and super-effective solutions for various embedded control application systems.

The furnace temperature control device of the verification furnace controls the temperature change rate of the verification furnace after constant temperature <= 2°C/min, and makes the deviation between the verification temperature and the set temperature of the verification furnace within ±5°C.

The system of the present invention realizes the corresponding protocol conversion from the RS232 interface to the process field bus, and from the RS485 interface to the process field bus, so that the equipment without the process field bus interface can be easily connected to the process field bus. The temperature range of 1500°C to 2300°C is used for data collection and calibration, which fills the gap in the industry at present.

Claims (6)

1. Wolfram rhenium heat electric couple calibrating data collecting system, its feature includes：The main website being connected by Process FieldbusROFIBUS and slave station, Wherein main website is included the class main website being interacted with slave station by described Process FieldbusROFIBUS and described Process FieldbusROFIBUS can be set Put and the two class main websites with a class master station communication, the standard that described slave station includes being connected with described Process FieldbusROFIBUS respectively is red Outer temperature collecting device and tested thermocouple harvester.

2. Wolfram rhenium heat electric couple as claimed in claim 1 examines and determine data collecting system, it is characterized by：A described class main website is PC Machine or PLC device.

3. Wolfram rhenium heat electric couple as claimed in claim 1 examines and determine data collecting system, it is characterized by：Two described class main websites include The control unit being connected with described Process FieldbusROFIBUS by network communication card.

4. Wolfram rhenium heat electric couple as claimed in claim 3 examines and determine data collecting system, it is characterized by：Described control unit is also connected with There is printing equipment.

5. the Wolfram rhenium heat electric couple calibrating data collecting system as described in one of Claims 1-4, it is characterized by：In described slave station Also include the assay furnace oven temperature control device being connected with Process FieldbusROFIBUS.

6. Wolfram rhenium heat electric couple as claimed in claim 5 examines and determine data collecting system, it is characterized by：Described assay furnace Control for Kiln Temperature It is provided with warning system in device.