High Performance Time Synchronisation for Industrial Logic Control Utilising a Low Cost Single Board Computer with EMC Compliance

Abstract

The integration of time transfer and control on a low cost single board computer (SBC) system is presented. The solution allows sub-microsecond level timestamping of logic control events and analogue to digital (ADC) measurements. The system is based on low cost, miniature commercially off the shelf (COTS) hardware. External time referencing can be supplied via network timing protocol (NTP), precision timing protocol (PTP) and/or a discrete pulse per second (PPS) signal. The operating distance is extendable to tens of kilometers using a simplified PPS transmission system over fibre, based on the Karoo array timing system (KATS) developed at South African Radio Astronomy Observatory (SARAO). Integration into the MeerKAT Radio Telescope's time and frequency modules shows CISPR 22 compliance and cross coupling effects for sensitive phase transfer systems are below the stringent EMC limits acceptable for radio astronomy. Real-time control is of great importance for industrial and scientific applications. After evaluating existing market-based solutions., these were found to be either cost prohibitive, non-EMC compliant or requiring proprietary network protocols. This implementation serves to offer a time synchronisation solution which is low in cost., has a small footprint and easily integrated into timing applications.