The 3x6000m3/h oxygen control system of Jiuquan Steel adopts the MACSV1.1.0 system of Hollysys. With the production of the second phase expansion project of stainless steel, the new nitrogen press of Atlas manufacturer is used. With independent control system, the self-developed ElektnmikcmMKIV controller, the operator records and starts and stops the data of the nitrogen compressor through the LED display next to the machine. This not only increases the labor intensity of the operator, but also is very unsafe. The operator is prone to misoperation and cause parking, and the operation next to the nitrogen press machine may cause personnel to leak due to nitrogen leakage. Therefore, the Elektnmikon MKIV controller needs to establish communication with the MACSV system through the Modbus protocol to remotely monitor the nitrogen compressor.
The 6000m3/h oxygen production of Jiuquan Steel is now composed of 3 sets of 6000m3/h air separation systems. The control system adopts the MACSV system of Hollysys to realize data acquisition, production process monitoring, process control, logic control and fast interlocking of air compressor, oxygen compressor, nitrogen compressor, liquid storage tank and other equipment. And other functions, the control system adopts distributed structure design, in which the main control unit adopts redundant configuration, which is used for engineering unit transformation and control calculation, and communicates with engineering station and operator station through monitoring network node (Ethernet); field bus (Prifl3US-DP) is connected with each intelligent I/O unit; the intelligent I/O unit becomes the data acquisition and control output of the site; the existing stainless steel expansion project adds a nitrogen pressure to the 6000m3/h oxygen system. The nitrogen press control system is a set of independent systems that are provided by the main equipment. The self-developed Elektnmikon MKIV controller contains a small LCD screen for displaying all the unit information, with various indications, alarms and safety. Function, reliable operation under conditions of large temperature changes. The controller is highly integrated and integrates its input/output interface and relay output terminals. At the same time, in order to overcome the shortcomings of its own I/O interface, the controller provides an I/O expansion interface to increase the available external The number of I/Os. The I/O unit for external expansion includes modules such as digital input and output, analog input and output, relay output dry contact, and external signal relay isolated input.
The protocol Modbus protocol packs ASC, RTU, TCP, etc., and does not specify the physical layer. This protocol defines the message structures that the controller can recognize and use, regardless of the network nodes through which they communicate. The standard Modbus port uses an RS-232C compatible serial interface that defines the pin, cable, signal bits, baud rate, and parity of the connector. When communicating on a Modbus network node, this protocol determines each controller's need to know their device address, identify messages sent by address, and decide what action to take. If the 2011 Procedural Engineering Equipment Technology Research Papers need to respond, the controller will generate feedback and send it out using the Modbus protocol. On other network nodes, messages containing the Modbus protocol are converted to frame or packet structures used on this network node.
Modbus protocol has two transmission modes. RTU mode communication uses 8-bit byte binary data communication, data check uses CRC cyclic redundancy check, and communication speed is faster; ASC11 mode uses 7-bit ASC code for communication, data check With LRC logic redundancy check, the communication speed is slow. In a communication system, only one communication method can be selected, and the two methods cannot be used together. The ASC and RTU protocols of Modbus specify the structure of messages, data, commands and responses. The data communication uses Maser/Slave mode. The Master sends a data request message. After receiving the correct message, the Slave can send data to the Master. In response to the request, the master can also directly send a message to modify the data of the aave side to achieve bidirectional read and write. The controller can be set to two transmission modes. When configuring each controller, all devices on a Modbus network must select the same transmission mode and serial parameters.
In the nitrogen compressor control system, the Elektamikon MKIV controller supports local control, remote control and LAN control. The system is easy to use. In the communication network node function, the controller itself is also equipped with LAN (CAN, ControlAreaNetwork) and RS485 (Modbus) standard interfaces, and the Modbus application is relatively mature. Therefore, the Modbus interface is used for communication, and the number can be performed from the controller and the operation station. Reading of quantity and analog data. There are two ways to communicate with the Atlas MCSV controller via Modbus: one is to install a M0XA converter directly on the servo, and connect directly to the RS485 port of the field PLC through this converter. To realize the communication between PLC and MACSV system of Modbus protocol; another method, you can add a FM020 communication module of Lishi Company, which supports Profibus-DP bus protocol and Modbus protocol, through Profibus-DP bus and controller Perform parameter and data exchange to realize DP slave function, and acquire or deliver Modbus data through Modbus communication protocol. Considering the actual situation of the on-site production, only the former method is studied. The Elektamikon MKIV controller is connected with the DCSMACSV system through configuration and communication to realize the remote monitoring function of the nitrogen pressure machine.
4.1 Establishment and configuration of Atlas communication The MKIV controller system independently developed a Combox-S module for data communication with third-party devices. It is a universal function serial communication module. After downloading the corresponding Modbus communication program, it will execute the Modbus-Proxy function. The module can be mounted on the DIN-Rail in the control cabinet or it can be installed separately. Before the module is powered, check that the power supply is 24VDC. Sub-D nine-pin plug pin 1 is grounded, pin 3 is positive, and pin 8 is negative.
The top LED lights of the Combox-S module are represented from left to right in order: Modek, unused. Observe whether the communication is normal by observing the status of the indicator. The Combox-S module is as shown: C0MB0X-S and the serial port of the connected computer are set as follows: Sleep communication protocol: MODBUS/RTU network structure: RS485 start bit: 1 data Bit: 8 check digit: None Stop bit: 1 Communication rate: 9600 485 Net link communication successfully tested as follows, this test can verify that the protocol converter works normally; at this time, the communication protocol converter has instructions 3, 4, 5, and 6. The light should be flashing.
485 network communication test interface 4.2 and the establishment and configuration of the time communication. Usually the historical data records are stored through the database mapping, and the database functions are also based on the service, so you can consider through the service The M0XA communication card with Modbus interface is installed on the device. The card is directly connected to the Atlas C0MB0X-S communication module by using the Modbus cable. The MACSV is used as the master station and the MKIV controller is used as the slave station to realize the MACSV. Communication between the system and the Atlas MKIV controller. Then install the interface software on the service device, and the communication execution file MvModbusMDT.exe. The communication software collects the device data of the field following the Modbus protocol into the MACSV system through the serial port, and can send the control command to the device, and the data is sent from the Modbus. Read or write in the interface, operate and archive in MACSV, so that all data and parameters in the nitrogen compressor self-contained control system can be recorded and operated in the existing DCS control system.
The communication software supports multiple analog data types, supports DCS system multi-domain, and supports dual-network redundancy in any domain. Using standard MODBUS protocol, RTU mode, as MODBUS master station for communication, support function code as shown in Table 1: Table 1 support function list request to receive switch quantity to send a single switch quantity request to receive analog quantity to send a single switch quantity to send a single analog quantity to send multiple Switch quantity sends multiple analog quantity one or two 2011 maintenance engineering department equipment technology research papers data channel table, substation address, serial communication baud rate, data bit, stop bit and other parameters, these data should be configured to MvMod-busMDT In the .INI file. The specific configuration is as follows: port configuration P0RT = 1 - serial port number TIMEOUT = 200 - read serial port data timeout, unit: milliseconds INSIDEINTERYAL = 50 - interval between commands, unit: milliseconds OUTERINTERYAL = 50 - interval between devices, Unit: millisecond BAUDRATE=9600——baud rate, unit: bit/second DATABIT=8-odd check, 2-even check) PERIOD=2000-communication cycle, unit: millisecond service slave 1 IP service 2 IP address 2SUBSTATI0NNUM=2 - the number of sub-station of the third domain SUB1ARGNUMBER=5 - the number of communication protocols of the first sub-station SUB2ARGNUMBER=5 - the number of communication protocols of the second sub-stition MULTIPLE1 = 1 - ―The first point zooming multiple P0INTTYP1=5——The first point data type 2011 Maintenance Engineering Department Equipment Technology Research Papers 1* Equipment I Connection>Ki Equipment The i-th HHSt's work 1 etc. The work "*4369* (proposed Dong IE 薷 ~ sleep | order third domain first sub-station second protocol configuration - first point name third domain second sub-station first protocol configuration =1 - the first point zoom factor P0INTTYP1 = 5 - the first point data type read and release
Send point configuration: The analog point sent by the MACSV system to the device is the existing data point in the MACSV project database. Just configure the tag variable name of the corresponding data in MvModbusMDT.ini. Analog quantity: In the service module configuration analog AM point, the value defaults to initial 0. Receive point configuration: The analog point received by the MACSV system is written into the MACSV project database, so the corresponding intermediate must be added to the MACSV project. variable. The AM point of station 0 needs to be added to the database master of the MACSV configuration software. After the configuration is completed, double-click MvModbusMDT.exe to communicate with the device. If the communication shows that the function code X of the Xth protocol of the X device is correct, the configuration file has no problem.
The configuration file path is incorrect or does not exist, as shown in the figure: the connection is not normal. 2) The communication is normal. The normal communication information is å‡ å£¬çŽ· å‡ å‡ ã€Š 《 åº åº åº 2011 2011 2011 2011 2011 2011 2011 2011 2011 2011 2011 2011 如果 如果 如果 通信 通信 通信 通信 通信 通信 通信However, the MACSV server does not normally receive the value of the communication software to write the service. It may be because the configuration of the file name and the configuration of the server are not corresponding or the IP address of the server is not configured correctly.
Through the communication between the Hollysys MACSV system and the Atlas Elektnmikon MKIV controller using the Modbus protocol, the communication between the Hollysys MACSV system and the MKIV controller is realized, and all the parameters of the unit are recorded in the existing DCS. In the control system, the unit can also be started and stopped directly at the DCS control system operation station, which ensures the integration of the control system, reduces the labor intensity of the operators, and achieves the purpose of increasing efficiency. At the same time, it has certain reference significance for other similar applications.
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