云南1米红外太阳塔分布式CCD实时控制与图像采集系统软件研制

Design of the Distributed Real-Time Control and Image-Acquisiton Software System for the YNAO 1m Solar Telescope

分布式多CCD实时控制与图像采集系统软件的研制是1 m红外太阳塔进入常规观测的必要条件。重点讨论了太阳塔多CCD实时控制与图像采集软件系统的研制,包括软件系统采取的主控前置系统结构、工作流程,为了解决主控机和前置机之间通信而设计的通信协议,利用双缓存、双模数变换器(Analog-to-Digital Converter,ADC)、存储器直接访问(Direct Memory Access,DMA)技术提高图像处理和存储速度,利用多线程机制实现多CCD的同步图像采集,前置系统定时向主控系统发送心跳信息以增强系统的可靠性。经实际测试,系统达到了预定指标,初步满足1 m红外太阳塔的观测需求。

The lm infrared solar tower is located at the Fuxian Solar Physics Observing Station, Yunnan Porvince. It is about 60 kilometers southeast of Kunming, the captal of the Yunnan Province, China. It will serve as a major ground-based optical and near-infrared solar observation equipment for China throughout the first few decades of this century, and is currently the world ＇ s largest vacuum solar telescope. This paper focuses on the design of its muhiple-CCD real-time control and image-acquisition software system. The software system adopts an overall architecture of master-to-front. In order to solve the problem of communication between the main-control and front-end systems, four kinds of application-layer communication protocols are designed： basic system initializing protocols, controlling protocols, status protocols, and parameter-setting protocols. In order to obtain a data processing speed matching the CCD recording speed, we use double- buffers and double-ADCs to receive the data from CCD, and use the DMA technology to directly transfer data from the storages of CCD to the memories of the front-end computer. The Socket, data-acquisition, and data- processing threads are designed for the front-end system and the main-control system to realize the synchronization for muhi-CCD image acquisition. The front-end system sends ＂heart-beat＂ information every 10 seconds to the main-control system to confirm it is active. Currently, the optical, mechanical, and electrical components of the solar tower have been completely installed. The Gigabit Ethernet, computers, and CCDs have also been installed. The software system described in this paper has been deployed and early-stage runnings show that it can serve the routine operations of the solar tower.