A control system framework for the Hobby-Eberly telescope

We present the development framework for the distributed control systems, scripting frontend, and monitoring facilities of the recently upgraded Hobby-Eberly Telescope (HET). A common flexible control and data acquisition layer in C++, with message passing implemented on top of ZeroMQ, wraps the final designs of each new hardware component including tracking, metrology, instrumentation and calibration equipment. A homogeneous command, response and event layer normalizes the diversity of the lower level software interfaces easing the development of the Telescope Control System (TCS). Applications developed in the framework easily interface to the new tracker and legacy instrumentation of the primary mirror, weather, dome, and tracker support structure. The framework facilitates testing, vetting, and characterization of the telescope and TCS. Examples of the real-time monitoring capabilities and the Python scripting methods of various telescope components yield insight into overall system performance. Lessons learned along the way, future refinements, and anticipated enhancements, are detailed.