利用FieldPoint系列模块实现水溶液晶体生长温度的精密控制与实时监测

A Precise Control and Real-time Monitoring System of Temperature of the Crystal Growth Based on the FieldPoint Series Module

介绍了一个使用成熟的实时控制技术对水溶液晶体生长进行精密温度控制的解决方案.该系统使用美国NationalInstruments(NI)公司的FieldPoint系列控制模块、LabVIEWRT的软件开发环境和自行优化设计的PID增量算法等技术,对晶体生长过程中的温度等重要参数进行精密、实时控制,不仅使该系统能够长期、稳定运行,而且具有自动数据采集、记录和实时显示,能够在局域网内发布,进行应急情况处理等特定功能.经过长时间闭环试验运行,该系统的控温精度已经达到百分之一度.

A solution applied in the precise temperature control system for the growth of aqueous crystal is proposed. The solution is based on an optimal Proportional-Integral-Differential increment algorithm,which is implemented using series of FieldPoint hardware and LabVIEW software produced by National Instruments. Firstly, the system builds the temperature data acquisition from the measurement circuits with FP-AI-110 module, which is the 16-bit resolution input module and includes 8 single-ended analog input channels (ADC). Then, the system processes these data in the FP-2000 module, which functions both as an embedded micro-processor and a network interface connecting a node of the FieldPoint I /O modules to a high-speed Ethernet network. With up to 100 Mb/s data communication rate and event-driven communications, the FP-2000 module delivers a high-performance network connection for FieldPoint that is easy to interface to a personal computer and easy to use. And finally, the system outputs 010V analog voltage signals to the power driving devices with FP-AO-210 module, which is the 12-bit resolution programmable output module with 8 single-ended analog output channels (DAC).The National Instruments LabVIEW Real-Time Module delivers deterministic real-time performance with an easy-to-use Windows-based development environment. The program of the precise temperature control and monitoring system is divided into two parts. In the first part, CrystalView Client can normally run on the host personal computer, and in the other part, CrystalView Server can smoothly run on the FP-2000 module, and it is independent of that host personal computer. In that case, the system program malfunctions that arise from the crash of the personal computer occasionally can be avoided. The communication between the personal computer and FP-2000 with real-time module is also available so that the measuring data and curves can be displayed on the screen of the personal computer if it is necessary. Depending on the DSTP protocol of the National Instruments, CrystalView Client can run on several personal computer in the laboratory, so that the Peer-to-Peer/Host Communication and the remote system explorer can be achieved based on the local network in the future. In summary, the system accomplishes the real-time control of the temperature and improves the control precision evidently. After long time closed loop experiments, the precision of 0.01 for this system hase been attained, and the data can be easily saved for the purpose of system maintenance.