Design and Development of a TCS Sequencer for the YNAO 2.4m Telescope

The control system the YNAO 2.4m Telescope at Lijiang uses the QNX real-time operating system and the CAN-Bus technology, realizing auto control (from a PLC system) of all control nodes of the telescope except the Telescope Control System(TCS) at the top operational level. All the instruments constructed for this telescope have their own control systems, which were previously independent of the TCS. The independence caused inconvenience in observation. The inconvenience is that different control interfaces needed to be used separately to control the telescope and the instruments in a complicated and low efficiency way. Meanwhile, some useful information produced by the TCS, especially the pointing/status information of the telescope and the important weather information could not be automatically written into a result-image FITS header. This put the burden on an observer to add the information into the header offline, passing the inconvenience into the data proceeeing. In this paper we introduce the design and development of a TCS Sequencer for the 2.4m telescope, including the system structure and the data flows of its programs. With the TCS Sequencer we have integrated the control systems of the 2.4m telescope and the mounted YFOSC camera. Currently, the telescope pointing/status information and weather information can be automatically written into a result-image FITS header; observers can control the telescope and instruments through a common control interface. Consequently, in using the telescope observation efficiency has been improved and data processing has been simplified. We also give certain results of using the TCS Sequencer and its running status. During this work we have also learned how to write C programs under a Linux OS and how to access a MySQL Database through a C program.