Research Of Measurement And Control System In Multiplexed Digital Ion Trap Mass Spectrometer

The mass spectrometer is a kind of analysis instruments with high sensitivity when it refers to material analysis and component identification. It is widely used in hot-spot fields such as drug discovery, food safety, border security and space technology, etc. With the rapid development of China’s economy and the improvement of science and technology in industry, analysis efficiency of domestic existing mass spectrometers cannot meet the demand in many fields. Therefore, high-throughput mass spectrometers become the major developing direction of today’s mass spectrometers.In order to improve mass analysis efficiency of mass spectrometers, this paper designed a measurement and control system based on ARM 11 microprocessor S3C6410, which enables all mass analyzers in multiplexed digital ion trap mass spectrometers to work at the same time. Because the transfer rate of mass spectrometers is high and high-speed data transmission may cause increased data error rate. This paper studied the hardware stability and error control method in high-speed communication and put forward improving measures of system reliability from hardware and software to reduce error rate.According to simulation and analysis of signal integrity problems in highspeed signal wires, the quantitative relationship between PCB layer parameters and signal integrity problems such as reflection, crosstalk and delay is determined. The design of embedded system hardware was put forward and hardware circuit with high stability was produced, which supports multichannel digital ion traps.Driver of bus communication and LCD display in the embedded system was programmed. Data transmission between communication and control board, signal producing module, dc output module and data acquisition module was realized. Meanwhile, network communication between the communication and control board and the computer was also accomplished.Considering that data flow deviation and data transition may occur during high-speed data communication in the measurement and control system, an error control method of software was put forward. Error detection ability of different cyclic redundancy check code was analyzed when it is used in the measurement and control system. Optimal generator polynomial is used to realize error detection in error control. A look-up table error correction method based on the cyclic redundancy check code is used to realize forward error correction in error control. Error correction performance of such a method was analyzed. And the result proves that this method can effectively improve the reliability of communication when additional error correcting code is avoided.The communication and control board of multiplexed digital ion trap mass spectrometer, which was developed in this paper, is equipped with high stability. It can effectively reduce the error rate in the process of data communication and improve the transmission reliability. Therefore, it can be part of measurement and control systems when multiplexed digital ion trap mass spectrometer is developed and integrated.