[Paper Review] Design and Performance Analysis of a Non-Standard EPICS Fast Controller

J. Jugo, Mikel Eguiraun+3 more|arXiv (Cornell University)|Jun 16, 2014

Particle Detector Development and Performance20 references3 citations

TL;DR

This paper proposes a LabVIEW RT-based EPICS fast controller using NI PXIe hardware for high-performance control in particle accelerators, enabling real-time signal processing and EPICS integration via a custom gateway. The approach achieves performance comparable to standard EPICS IOCs but with faster development, though it shows instability under heavy simultaneous monitor loads beyond 80 monitors.

ABSTRACT

The large scientific projects present new technological challenges, such as the distributed control over a communication network. In particular, the middleware EPICS is the most extended communication standard in particle accelerators. The integration of modern control architectures in these EPICS networks is becoming common, as for example for the PXI/PXIe and xTCA hardware alternatives. In this work, a different integration procedure for PXIe real time controllers from National Instruments is proposed, using LabVIEW as the design tool. This methodology is considered and its performance is analyzed by means of a set of laboratory experiments. This control architecture is proposed for achieving the implementation requirements of the fast controllers, which need an important amount of computational power and signal processing capability, with a tight real-time demand. The present work studies the advantages and drawbacks of this methodology and presents its comprehensive evaluation by means of a laboratory test bench, designed for the application of systematic tests. These tests compare the proposed fast controller performance with a similar system implemented using an standard EPICS IOC provided by the CODAC system.

Motivation & Objective

• To develop a high-performance, real-time control architecture for particle accelerators using COTS PXIe hardware and LabVIEW RT.
• To enable seamless integration of LabVIEW-based controllers into EPICS networks via a custom communication gateway.
• To evaluate the performance and robustness of the proposed architecture against standard EPICS IOC implementations.
• To identify scalability limits, particularly under high PV and monitor loads, and propose mitigation strategies.

Proposed method

• Implementation of a real-time controller using National Instruments PXIe hardware with FPGA and RT modules.
• Development of an EPICS Channel Access (CA) server within LabVIEW Real-Time (RT) for direct EPICS network communication.
• Design of a communication gateway to expose LabVIEW-based control logic as a full EPICS IOC.
• Use of the DSC (Distributed Shared Memory) module in LabVIEW to manage EPICS PVs and monitor events.
• Creation of a laboratory test bench to systematically compare the proposed system with a standard CODAC-based EPICS IOC.
• Benchmarking under varying workloads: PV count, get requests, and simultaneous monitor connections.

Experimental results

Research questions

• RQ1 How does the performance of a LabVIEW RT-based fast controller compare to a standard EPICS IOC in terms of latency and throughput?
• RQ2 What are the scalability limits of the LabVIEW EPICS server under high numbers of PVs and simultaneous monitors?
• RQ3 Can a LabVIEW-based system achieve reliable real-time behavior suitable for large-scale accelerator control?
• RQ4 How does the initialization time of the LabVIEW-based system compare to standard EPICS IOC deployment?
• RQ5 What are the key performance bottlenecks in the LabVIEW EPICS integration, and how can they be mitigated?

Key findings

• The proposed LabVIEW-based controller achieves performance comparable to standard EPICS IOCs for typical control workloads.
• The system supports up to 16,000 PVs per controller, representing an eightfold increase over baseline configurations.
• The system handles up to 180 PVs per get request without performance degradation.
• Beyond 80 simultaneous EPICS monitors, the LabVIEW-based system exhibits instability, including random hangs during data requests.
• The initialization time for the LabVIEW-based solution is longer than for the standard EPICS IOC.
• The gateway architecture enables transparent EPICS integration and supports future enhancements to improve monitor scalability.