The Complexity of Modern Control Systems

Modern scientific facilities, such as the Diamond Light Source (UK) and the Australian Synchrotron, require the orchestration of thousands of interdependent axes. These systems are typically built upon distributed control frameworks—primarily EPICS (Experimental Physics and Industrial Control System) and TANGO.

The fundamental engineering hurdle is the "Integration Gap": the difficulty of interfacing high-speed, deterministic motion controllers with the high-level, distributed database architectures of EPICS/TANGO without introducing unacceptable latency or complexity in the control loop.

The Integration Gap

Control engineers managing beamline or telescope-scale projects face three critical technical bottlenecks:

1. Protocol Translation: Translating low-level motion commands (trajectories, homing, limits) into high-level EPICS/TANGO records.
2. Software Scalability: Managing the deployment of device servers across hundreds of nodes in a distributed network.
3. Hardware Abstraction: Providing a unified interface that allows researchers to interact with complex hardware (e.g., Piezo-actuated mirrors, X-ray slits) through standard software toolkits like LabVIEW or Python.

The Integrated Solution: A Layered Architecture

The collaboration between Delta Tau and Observatory Sciences provides a vertically integrated solution stack that addresses the hardware-to-software transition.

The Hardware Layer (Delta Tau)

The foundation of the system is the Delta Tau PowerPMAC and GeoBrick LV architecture.

• High-Density Control: Capable of managing up to 256 axes per controller.
• Deterministic Performance: High-speed execution of motion profiles with minimal jitter.
• Advanced IO: Integration of analog-to-digital converters (ADC) and high-speed sensors directly into the motion loop.

The Integration Layer (Observatory Sciences)

OSL provides the critical "Software Bridge" that enables the hardware to function as a native part of the facility's distributed database.

• EPICS Device Support: OSL has engineered specialized EPICS drivers for the Power PMAC, enabling trajectory scanning, real-time logging, and dynamic coordinate system swapping.
• TANGO Device Servers: Development of TANGO based architectures that allow for object-oriented monitoring and control of Delta Tau hardware across a network.
• Linux/C++ Toolkits: Deployment of Linux kernel drivers and SSH-based C++ libraries for secure, low-latency communication between the controller and the control network.

Implementation at Diamond Light Source (DLS)

The implementation at Diamond Light Source serves as the definitive proof of concept for this integrated architecture.

• Phase I & II Deployment: During the expansion of DLS, OSL consultants worked alongside Delta Tau UK to implement over 1,500 axes of motion.
• Next-Generation Controller Integration: The transition to the Delta Tau LV-IMS (PMAC) was facilitated by OSL’s development of embedded EPICS software, allowing for "plug-and-play" integration into the existing DLS control infrastructure.
• Complex Beamline Control: OSL engineers utilized the PMAC platform to manage highly specialized components, including piezo-actuated mirrors (Bimorphs) and high-speed shutters (300µs opening times), all integrated via the EPICS framework

Technical Specifications & Availability

To support the global scientific community, key components of this integrated solution are maintained and, in some cases, made open-source:

• EPICS Support Modules: Available via GitHub (e.g., dls-controls/pmac), maintained for high-reliability environments.
• TANGO Device Servers: Specialized software for PowerPMAC monitoring and control.
• LabVIEW VIs: Driver interfaces for rapid prototyping and GUI development in laboratory settings.

Conclusion

The synergy between Delta Tau’s motion control hardware and Observatory Sciences’ software expertise provides a robust, scalable solution for the world's most demanding scientific applications. By bridging the gap between deterministic hardware and distributed software frameworks (EPICS/TANGO), this partnership enables control engineers to deploy complex, multi-axis systems with reduced commissioning time, enhanced reliability, and a simplified software lifecycle.

Contact Information For technical inquiries regarding hardware integration, device driver development, or EPICS/TANGO consultancy, please contact Observatory Sciences Ltd

Focus Areas: Synchrotron Beamlines, Astronomical Observatories, Distributed Control Systems (DCS). 

Keywords: Power PMAC, LV-IMS, EPICS, TANGO, Deterministic Motion, Beamline Commissioning, Device Support.

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