CN1952624A - Automatic verification control system for water flow standard device - Google Patents

Abstract

The invention provides an automatic verification control system for a water flow standard device, which is connected by a computer and a PLC. The PLC completes the operation of the verification program, the collection of detection data, and the calculation of technical indicators. The computer directly reads from the PLC through communication software. Obtain data, use monitoring software to make monitoring screens, use the built-in VBA of monitoring software to combine with monitoring software and VisualBasic software, generate real-time verification records and establish background databases, and query and print verification records. The invention replaces the traditional verification method of manual filling and calculation item by item, which not only reduces the mistakes of human copying and calculation, but also improves the accuracy and authority of the detection data, and achieves simple operation, advanced control, high verification accuracy, and equipment The purpose of low failure rate.

Description

Automatic Calibration Control System of Water Flow Standard Device

technical field

The invention relates to an instrument verification control system, in particular to an automatic verification control system for a water flow standard device.

Background technique

The water flow standard device is a standard device for testing liquid flow meters, mainly composed of liquid circulation system, test pipeline, flow working standard (weighing container) experimental start-stop equipment and control equipment (as shown in Figure 3). Its working principle is: install the tested flow meter on the standard device, make the liquid flow through the tested flow meter and the flow working standard (weighing container), and synchronously operate the tested flow meter and the flow working standard (weighing container), Compare the output flow values of the two to determine the measurement accuracy and repeatability of the tested flowmeter. The verification methods mainly include static mass method and volume method. The static mass method is to weigh the mass of the liquid in the container for a period of time in a static state to calculate the flow rate. According to the requirements of the verification regulations, the verification points of the flowmeter are generally five points of 25%, 40%, 60%, 80% and 100% of the maximum flow rate. Liquid quality, one is to collect the flow rate of the flow meter to be tested, and perform a large number of complicated calculations and fill in the verification records based on the test data. The previous control system was old-fashioned relays, press buckles, and buttons. All operations were performed on the control box. The verification method was single-machine control. During the verification, the shut-off valve was manually opened, and the flow rate was manually adjusted to a certain value, and the flow meter was manually read. Indicate the value, then measure the height of the water in the weighing container, convert it into volume unit flow, and calculate the relative error, repeatability and instrument coefficient of the flowmeter after a large number of manual calculations according to the verification regulations. The verification method is outdated and backward. The flow meter requires the cooperation of multiple people to complete. More importantly, due to manual operation, reading and calculation, it is easy to cause inaccurate data and low verification accuracy of the system. It is difficult to guarantee the accuracy of the tested meter, and it is impossible to provide reliable technical data for production, which directly affects the quality of products and enterprises. economic benefits.

Contents of the invention

The purpose of the present invention is to provide an automatic verification control system for a water flow standard device, so that the entire verification process is completely controlled by a computer, and a verification record of real-time data is generated during the verification process, and it is also convenient for querying and printing of the verification record.

The object of the present invention is achieved in that the automatic verification control system of the water flow standard device is mainly connected by a computer and a PLC. The PLC completes the operation of the verification program, the collection of test data, and the calculation of technical indicators; the computer directly obtains data from the PLC through communication software, uses the monitoring software to make monitoring screens, and uses the embedded VBA of the monitoring software to combine with monitoring software and VisualBasic software. Generate real-time verification records and establish a background database, as well as query and print verification records.

Due to the above-mentioned system configuration of the present invention, the automatic control of the electrical control process, the collection of detection data, the calculation of technical indicators, the query and printing of verification records is realized through the verification program, replacing the traditional verification method of manually filling in and calculating item by item. In this way, the error of human transcription and calculation is reduced, and the accuracy and authority of the detection data are improved, so as to realize the purpose of simple operation, advanced control, high verification accuracy and low failure rate of equipment.

Description of drawings

Fig. 1 is a control system composition diagram of the present invention;

Fig. 2 is the verification program flowchart of the present invention;

Figure 3 is a structural diagram of the water flow standard device.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

As shown in Fig. 1, the automatic verification control system of the water flow standard device of the present invention is mainly connected by a computer with the AB-PLC through the RS-232 interface. Use RSlogix500 software to make AB-PLC complete the operation of the verification program, the collection of detection data, and the calculation of technical indicators through programming; the computer directly obtains data from the PLC through RSlinx communication software, and uses RSView32 monitoring software to create convenient and intuitive operation screens and process screens , Verification record screen, easy to operate and control. The development tool adopts VisualBasic software, and uses the embedded VBA of RSView32 software to combine with RSView32 software to generate real-time verification records and establish a background database, which is convenient for querying and printing of historical records.

As shown in Figure 2, the verification program is designed according to the verification regulations, which can be divided into manual and automatic. Choose PC manual to realize stand-alone operation. Select PC to be automatic, start the air compressor and wait until the pressure of the air compressor reaches above 0.4MPa, press the selected calibration line, start the water pump to pump water to the water tower, when the liquid level of the water tower reaches the overflow state, it will be controlled by PLC Open the shut-off valve, adjust the opening of the regulating valve to 90% of the maximum flow, run for 5 minutes, close the regulating valve and the shut-off valve; then adjust the opening of the regulating valve to 25%, 40%, 60% of the maximum flow in turn %, 80%, and 100% of the verification points; each verification point shall be verified three times, and at each verification point, the mass of the liquid in the container and the flow rate of the inspected flowmeter shall be collected and weighed for a period of time. Then carry out relevant calculations on the collected data according to the requirements of the verification regulations, and judge whether the flowmeter is qualified according to the calculation results. After the PLC issues the command to generate the report, it starts the event trigger function. When the manual input verification record number and the event trigger signal are available, the VBA program calls the Excel table of the verification record stored in the background database under the specified path, so that each verification record The weighing value of the water in the one-point flowmeter and the container, the flow rate of the flowmeter, the relative indication error, the meter coefficient, the repeatability and the relevant data of the flowmeter are all dynamically written into the verification record, and the verification record is printed and recorded. Save in the specified location. After all the verification is completed, close the regulating valve and shut-off valve to complete the verification of the flowmeter.

As shown in Figures 1 and 2, since the display output of the flowmeter is a 4-20mA analog signal, we use a 16-bit 8-channel analog input module 1746-NI8 to collect the flow of the flowmeter to obtain the real-time flow of the flowmeter. In order to ensure the accuracy of the flow rate collected by the flowmeter, we do not collect the flow rate of the flowmeter in the first 10 seconds when the reversing valve is opened and closed, but collect the flow rate every 1 second during the middle period, and then take the average value as the flow rate of the flowmeter.

As shown in Figure 1, in order to ensure the verification accuracy, the collection and weighing of the liquid quality in the container for a period of time is realized by using the 1747-SN module and the weighing display instrument connected to the container. The method is to design an RS-232 interface on the weighing display instrument, set the interface and baud rate in the weighing display instrument, and then connect it to the scanning module of the PLC through the communication cable, and carry out corresponding operations in the scanning module. The baud rate is set, so that the scanning module displays the weighing value of the weighing display instrument on its address, and the PLC reads the weighing value of the weighing display instrument from the specified address, and completes the quality control of the water in the container. collection.

The operating system of the present invention adopts Windows2000, and the purpose is to facilitate generating reports in the monitoring software.

The system configuration of the present invention is as follows:

serial number The device name Specification unit quantity 1 PLC host 1747-L542C set 1 2 input module 1746-IB16 indivual 1 3 output module 1746-OW16 indivual 1 4 Analog Input Module 1746-NI8 indivual 2 5 Analog output module 1746-NO4I indivual 2 6   Scan Module 1747-SN indivual 1 7 programming software RSLogix500 set 1 8 Monitoring software RSView32 (including Linx) set 1

The system configuration of the present invention is not limited to the specific equipment listed above, and other equipment similar in performance to the equipment listed above can also be used for system configuration.

Claims (6)

1. A water flow standard device automatic verification control system is characterized in that it is connected by a computer and a PLC, and the PLC completes the verification program operation, the collection of detection data, and the calculation of technical indicators, and the computer directly reads from the PLC through communication software. Obtain data, use monitoring software to make monitoring screens, use the built-in VBA of monitoring software to combine with monitoring software and VisualBasic software, generate real-time verification records and establish background databases, and query and print verification records. 2. The automatic calibration control system of water flow standard device according to claim 1, characterized in that said PLC is AB-PLC, which is connected with a computer through RS-232 interface, and the computer directly reads from the PLC through RSlinx communication software. To obtain data, the computer monitoring software uses RSView32, and the PLC programming software is RSlogix500. 3. The automatic verification control system of the water flow standard device according to claim 1 or 2, characterized in that the collected detection data includes the quality of the liquid in the container and the flow rate of the flowmeter. 4. The automatic verification control system of water flow standard device according to claim 3, characterized in that the collection method of the liquid quality in the container is to design an RS-232 interface on the weighing display instrument, in the weighing display instrument Set the interface and baud rate, and then connect to the scanning module of the PLC through the communication cable, and set the corresponding baud rate in the scanning module, so that the scanning module will display the weighing value of the weighing display instrument on its On the address, the PLC reads the weighing value of the weighing display instrument from the specified address. 5. The automatic verification control system of the water flow standard device according to claim 3, wherein the flow rate of the flowmeter is collected by a 16-bit analog input module 1746-NI8 to obtain the real-time flow rate of the flowmeter. 6. The automatic verification control system of the water flow standard device according to claim 1 or 2, characterized in that the monitoring screen includes an operation screen, a process screen, and a verification record screen.

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