Delta Tau tales of motion control

One of the most common requirements for Delta Tau projects, whether it is for an astronomical or a high-energy physics application, is software for motion control. These clever products can handle the demanding requirements of optical telescopes needing precise and synchronised motion control of the telescope mount. But then most high-energy physics facilities incorporate large numbers of motion axes that are used to position and move experimental equipment and here again Delta Tau is a leading supplier.

Working in collaboration with motion control applications software engineers from Observatory Sciences (OSL), Delta Tau has been involved in motion control applications for many years with a lot of experience gained using the Delta-Tau PMAC (Programmable Multi Axis Controller). Back in the 1990s, PMAC controllers were adopted by the Gemini telescope project to control the elevation and azimuth axes of the twin 8m telescopes.

An OSL consultant worked to integrate them with the EPICS software framework that was used throughout the Gemini control system. The work included enhancing the EPICS driver software to support Fast Data Logging on the PMAC itself, at the 2kHz servo rate. This proved extremely useful in commissioning where the data was fed into Matlab for 'on-the-spot ' analysis of problems and help with servo tuning.

The Gemini system used a VMEbus interface for their PMAC systems, with software running under the Wind River vxWorks real-time operating system. More recently, large experimental control systems have begun to use the Linux operating system and the Australian Synchrotron Project has adopted EPICS with Linux as their software platform. German beamline supplier Accel has supplied several beamlines to the Australian Synchrotron, and Observatory Sciences worked with them to produce a Linux driver for the Delta Tau PMAC2 Ultralite motion controller card. This driver is available as open-source software and can be downloaded from the OSL website. At the Diamond Light Source (DLS) in the UK an incredible 800 motion axes is being installed using Delta Tau controllers to control components in the second phase of synchrotron beamlines. These complement the 700 already installed in the first phase. OSL has worked with Delta Tau PMAC systems throughout the Diamond control system on beamline commissioning and enhancement work being performed by OSL consultants based at DLS.

The Delta Tau GeoBrick LV was designed especially for Diamond and can control up to 8 axes of mixed servo and stepping motor types. The latest development of this system has seen OSL produce EPICS software embedded in the GeoBrick LV-PC, to enable plug-and-play EPICS software integration. OSL also worked with Micromech in this successful bid to supply Diamond with Delta Tau's next generation of PMAC motion controller.

Micromech is the authorised systems integrator for Delta Tau high level, multi-axis control products.