Fermentation engineering, the use of large-scale cell culture technology has been deep into medicine, light industry, food, agriculture, environmental protection in various fields, a large proportion of the national economy. It has important economic and social significance to improve the fermentation level. Based on the theory of scale-up and optimization of fermentation process, the theory of scale-up and optimization has made great achievements in the scale-up and optimization of fermentation engineering. Because of the complexity of the fermentation process and the highly nonlinear factors and multicapacity process characteristics, makes the system is dynamic and unpredictable, and the fermentation conditions of severe, such as high temperature, high humidity, long period of fermentation bioreactor control system put forward strict requirements. The bioreactor control system based on FX2n series PLC controller is a new supporting platform for the scale-up and optimization of fermentation engineering.
Technical requirements of control system
1. The temperature data of pH, the temperature, the dissolved oxygen and other environmental parameters of the bioreactor control system are continuous.
2) actuator, most of the switch, such as solenoid valves, diaphragm valves and other types of valves, the gap between the work of various types of feed pump, etc..
3 part of the analog output, such as the speed control of hybrid motor.
4) process characteristic variables are divided into direct and indirect variables. Fermentation engineering, biological reaction process, contains many difficult to directly measure the biological characteristics of the process variables, such as the oxygen uptake rate OUR, CO2 release rate of CER, RQ and other respiratory quotient, the indirect variables on the study method of multiple scales of the new fermentation scale-up and optimization is of great significance based on only the direct variable direct measurement of the use of soft measurement technology, the function of operation, mapping. The accuracy, stability and operational capability of the control system determine the quality of the whole system.
5) with the promotion of Internet technology, modern information technology is entering into every area, and the fermentation process based on parameters related to the study of multi scale amplification and optimization technology theory, is a new concept, is gradually developing, collaborative efforts require domestic experts in various fields, the system should have an open communication interface. LAN in the workshop range, and through Internet, the remote terminal can browse the site data, or to intervene.
3 system components
According to the above technical requirements and past experience, we feel that the selection of Mitsubishi Co FX2n series PLC is appropriate. FX2n series PLC has a variety of extension modules can be selected, such as FX2n-4AD-PT, FX2n-4AD, FX2n-232-Bd expansion module, suitable for analog input and data communication; the switch can be directly output; FX2n series PLC instruction set, covering most of operation. The double byte floating point instruction satisfies the precision of measurement and operation. Site accurate sensor to detect a variety of physical, chemical, biological parameters, such as input FX2n-4AD-PT and FX2n-4AD block, PLC output after the operation of the control actuator, and shop floor data exchange. Human machine interface using Mitsubishi Co A975GOT-TBA-B, 10.4 inch LCD screen with touch keys, the screen is rich, but also prepared a number of user help screen, providing online help, user-friendly. The field control station is located beside the bioreactor, and all kinds of sensors and PLC are installed in the same control cabinet. The transmitter, PLC and other power supply circuits are equipped with AC filters. Communication with twisted pair cable chain to the workshop operation station, compared with the PC-BASED structure, simplifies the wiring. Workshop operation station with IPC, Ethernet, PC and other machine LAN; C++ write multi-threaded, multi task software package for data analysis, trend curve, query, print and other functions, and the integration of TCP/IP, easy to access remote terminal in Internet network