Application of PLC in Air Pressure Unit Monitoring System

2 Shandong University of Science and Technology Li Liangbao Cao Maoyong Sun Nongliang 1 Introduction In the coal mining production, the full air compressor referred to as the air compressor is mainly responsible for providing power to a large number of pneumatic machinery in the mine. The reliability and safety of its work directly affects The normal production and economic benefits of the mine.

At present, most air compressor units have backward control methods. The operation is inconvenient to ask. Most of the control loops are relay control, control mode, and local manual operation. The fixed personnel are on duty for 24 hours. The maintenance personnel manually start or stop the air compressor according to the demand of the underground air volume, and the timing inspection records the operation status. In addition, the air compressor unit consumes a large amount of electricity, and for a long time, it is operated under no-load or light-load conditions, resulting in a large energy consumption and a serious operation cost. Therefore, it is of great practical significance to design a fully automatic centralized monitoring system with convenient operation and perfect function to monitor and protect the air compressor unit, improve the working efficiency of the air compressor unit, reduce energy consumption and prolong the service life.

2 The composition of the monitoring system The air compressor room of this project has a 0, 6 4 B 250 type oil injection screw with a speed of 1485, claws, free displacement of 42.7 claws 3, maximum exhaust pressure of 7.53. Each air compressor All are equipped with a body controller, 683100, through the operation panel of the 63100 controller, the staff can control the start and stop of a single air compressor on the spot, see the operating conditions to set the operating parameters. In addition, the 61C3100 controller has a 8 485 communication interface and supports the ModbusRTU protocol, which provides conditions for centralized monitoring of air compressor units. System structure

No. 1 air compressor No. 5 air compressor 2. The configuration design system uses Siemens 373000 to achieve centralized monitoring.

The 57300 is a modular structure with the advantages of complete modules, convenient communication, strong and stable operation, and is especially suitable for industrial environments and electrical interference environments. According to the system control requirements and consider leaving the fixed power module 5307 input voltage is 220, the output voltage is 2400, the output current is 5-6, and the other modules are powered.

And the core of the processing, there are 48KB of random memory and 80KB of load memory, each execution of 1 instruction requires about 3 out of 5, the maximum expandable 1024 points of digital or 128 analog channels. It has an MPI communication port and a 0 communication port, 41 ports for connecting to the touch screen, the port is used for monitoring when the program is debugged, the program is running and the program is downloaded, and is reserved for future system expansion.

The digital input module SM321 is equipped with three models of DI21x24, 00 34321 module, collecting the status signal of the high voltage switchgear that supplies power to the air compressor, such as the high voltage allowable pressure fault closing feedback, the feedback feedback, the trolley is in place, etc. The status signal of the automatic switch and the emergency stop button corresponding to the press.

The digital output module SM322 is equipped with two SM322 modules of model D016x24VDC0 and 5AREL. The control signals of the output PLC such as start stop, load unloading, emergency stop, etc., control the air compressor operation.

The communication module fast 03410341 module 131 is a serial communication processor module. The hardware interface can be adjusted by the ruler 3232, Kenting or ruler 8422485, integrated with the 3964-foot 51280 communication protocol, and supports the user loading protocol. The system selects the 0341 module with the interface of 8485 standard, and inserts the river in the 0341 communication module. The north station is 0, and the module loading rib is still agreed, so that the 0341 module becomes the 8 main station. The 0341 module utilizes the North 1 protocol based on the 5485 bus, communicates with the 6,53100 controller as the river, and the 6,53100 controller, and collects the air compressor operating status information stored in the 683100 controller.

1 is a communication processor module for connecting industrial Ethernet. The 10 system is connected to the Ethernet and is responsible for communication between the B and the host computer.

2.2 Touch screen configuration design system uses Siemens Ding, 27010 type touch screen as a workshop-level centralized monitoring station. It is based on the standard operating system tear 080, such as 0 rating 8, Qiu Neng, stable and reliable, user-friendly, visual, easy to operate and manage.

The operator can view the operating status and real-time data of the air compressor through the shape and menu, set the operating parameters such as the pressure time of the air compressor, view the historical data fault alarm information of the system, and set whether to allow the remote control of the upper computer. Air compressor. The touch screen visually shows the cumbersome work of the air compressor unit, which greatly improves the work efficiency and management level.

2.3 The upper computer configuration design system is adopted, and the machine is used as the remote monitoring station of the upper computer. Monitor the operation status of the air compressor online through the network, view real-time data such as pressure and temperature running time, motor voltage motor current output power, record and store historical data, and provide data, query and print functions. When the field device has an action or a fault, it can pop up a message and record it. If the remote control allows it, the duty officer can also remotely control the air compressor. Remote monitoring facilitates scheduling and raises the level of management automation, which is the need for the development of coal mine information.

Other components include hand automatic transfer switch emergency stop button sound and light alarm.

3 Communication system The communication in the system consists of parts.

3.1 Field device communication and communication between the 633100 controllers 14 The control is convenient to design a simple ruler 5485 interface standard as a physical communication standard.

The rule 5485 standard requires two-wire differential transmission and reception of data, so it can effectively overcome common mode interference to suppress line noise. According to the actual situation, the communication protocol adopts the M0dbUs protocol of the single-master multi-slave structure, and the Modbus RTU communication mode is selected. The RS485 standard is the physical layer standard of the bus, which is responsible for level conversion and data transceiving. The Modbus protocol forms the data link layer protocol of the bus, which specifies the format of the data frame transmitted on the bus, which is transmitted between the master station and the slave station. The data provides a communication protocol to ensure that valid data is reliably transmitted between the station and the slave, and the two together form the 8485 bus.

The 341 module is set as the master station of the bus, and the 6,53100 controller is set as the slave of the bus. Each slave station is assigned a unique address. The communication speed of the master station and the slave station is set to 76.88. The command is used during operation. The communication mode of the response, each command frame corresponds to a response frame, and the 5 protocol defines a plurality of function codes for the command frame, and different function codes require the slave station to perform different responses. The function code used in the system is 03, which is the register of the 653100 controller.

In the response frame, the number of bytes refers to the number of bytes of the internal register data that the primary station requests from the secondary station, and the register 12 refers to the contents of each of the transmitted registers, and the ruler has the same meaning as in the command frame.

Finally, it should be noted that the ruler 5485 bus is only used for data acquisition, and the control signal is output by the digital output module 5322, which is transmitted to the control relay of the air compressor itself through the signal line, which is determined by the real-time requirements of the site. . If the control signal is also sent by the 341 module, it needs to be transmitted to the 6,83100 controller via the 8485 bus. Then, the 683100 controller controls the control relay 1 of the air compressor and directly transmits the control signal to the hard wiring. The control relay of the air compressor greatly shortens the control response time of the system. At the same time, the 8485 bus can collect real-time data at a faster speed. 3.2 The communication between the touch screen communication 10 and the touch screen is Siemens products, through MPI. The cable is connected to the MP1 communication port of the PLC and the RS485 communication port of the touch screen. During configuration, the relevant communication parameters such as the desired connection, the address of the port and the slot number are defined. The interface type is MPI, and the baud rate is set to 187.508 for simple configuration operation.

3.3 Host computer communication In the communication between 10 and the host computer, 1 through the Ethernet module, 431 is connected to the industrial Ethernet, and the host computer realizes the remote monitoring function through the network. Select the interface type as Industrial Ethernet, the communication rate is lOOMbps, and set the IP address of the PLC and the host computer.

4 The software design system control requirements are as follows: The manual automatic transfer switch is a manual air compressor, which is only controlled by the 683100 controller to facilitate machine maintenance and maintenance. At this time, only the data in the 683100 controller can be collected. The air compressor that can't control the automatic changeover of the air compressor's automatic switch and the remote control is invalid will be centralized and supervised by 10, and 10 will determine the number of air compressors to be operated according to the change of wind pressure, and maintain the wind pressure. Meet the needs of underground wind, and according to the length of the air compressor running time, they rotate work. When the remote control setting on the touch screen is invalid, the upper computer can only monitor the running status of the air compressor without control authority. When the control is effective and the automatic hand switch is in the automatic state, the air compressor will be remotely controlled only by the host computer.

4.1 monitoring program design 8 D 75.382 programming software package, it uses structured programming, program readability, easy to adjust and maintain. The main program flow of a single air compressor 4.

The B0 control program mainly has the following functions for automatic rotation operation. 1 According to the signal collected by the bus for comprehensive judgment, and then issued a start stop load unloading alarm and other control commands, monitoring the air compressor unit automatic operation, so that the manifold pressure is maintained between the set pressure lower limit value and the upper pressure limit value. If the wind pressure is lower than the lower limit of the pressure, the number of air compressors is increased. If the wind pressure is above the upper pressure limit, the number of air compressors is reduced, which can meet the needs of downhole wind consumption and reduce energy consumption.

After 8 hours of continuous operation of the air compressor, the temperature of the fuselage will be very high. It needs to be shut down and used to dissipate its own heat to ensure that the machine is not damaged.

Therefore, the air compressor needs to be rotated to ensure safe and reliable operation of the air compressor and prolong the service life of the equipment. According to the running time, the air compressor controlled by 0 will be sorted to establish the boot sequence and the stop sequence. When it is necessary to increase the number of air compressors, the air compressor with the shortest total running time will be started. When the number of running units is 0, the air compressor with the longest running time will be stopped.

Delayed start and delayed stop. 10 itself has strong anti-interference ability, but due to various complicated factors such as the wind conditions of the grid in the field, the motor current motor voltage and other disturbances will cause false alarms, if the disturbance of the manifold pressure occurs at the lower pressure limit. Near the value or the upper limit of the pressure, when they are treated as a general work, frequent startup and shutdown will occur, which will affect the reliability and service life of the equipment. Therefore, it is necessary to perform appropriate delay processing on the originating signal of the motion instruction to eliminate the disturbance and prevent malfunction.

Intelligent protection. When the main motor of the air compressor starts, the starting current is 57 times of the rated current, which has a great impact on the power grid and other electrical equipment, and also affects the service life of the air compressor. Therefore, the air compressor should not be started frequently. In order to enable the system to accurately judge the wind condition and control the start of the air compressor according to this, the air compressor is started frequently during the downwind period, and when the two start time intervals are less than the preset value, Keep the air compressor running continuously without stopping. When the interval between two consecutive loadings is long, it can be considered that the peak period of the wind has passed and the air compressor is in intermittent operation. In addition, the motor current motor voltage, exhaust pressure, intake negative pressure, operating temperature, oil temperature, oil pressure difference, and other important parameters are monitored in real time, and an abnormality occurs in time for failure alarm and processing.

4.2 Touch screen man-machine interface design and selection of touch screen Ding, 270 supporting configuration software, printing 1 design interface. The screen includes the operating status of the main screen air compressor unit and the display of the main parameters. 2 Datagram real-time data summary, and can query historical data and manifold pressure curve. 3 Run setting settings to start the remote control is valid, set the pressure threshold for automatic start stop load unloading, set the time parameter alarm parameters and so on.

4 alarm inquiry, query alarm details. 5 system management.

4.3 PC monitoring program design PC monitoring software selected Siemens based on 14 to 8 environment configuration software sector 06.0 version. Mainly reported by the monitoring screen in real time, monitoring screen 5.

5 Conclusion B. It has a relatively good price/performance ratio, but it is not compatible with the communication protocol supported by the field device, and the system adopts it. The 341 module has 4, and the plan of the North 8 main station has a definite practical significance. On-site commissioning and operation, the system is stable, safe and reliable, improves the operating efficiency of the air compressor unit, and realizes automation of monitoring and management. The system can be applied not only to the monitoring of air compressors in coal mines, but also to other occasions.

Male postgraduate research direction control theory and control engineering port into the 00,3100 intelligent controller operation manual mast air compressor 2 Liu cone, Zhou Hai. Ximen Festival Chinese company. Deep people wash out Siemens 5730 Beijing Beijing University of Aeronautics and Astronautics Press, 2004 131 Liao Changchu. 87300400 application technology. Beijing Machinery Industry Press, 2005 Wang Weibing Fan. It is a financial extension and network interconnection technology. Beijing Machine Industry Publishing House, 2004 manual, it seems to be a touch. ,this