NI: 1st IEEE 1588 PCI interface for distributed synchronization
Engineers now can use the new National Instruments PCI-1588 interface to synchronize clocks and events on multiple distributed devices with submicrosecond precision using the IEEE 1588 precision time protocol (PTP), the company says.
The new interface can be used to develop synchronized data acquisition systems and to synchronize IEEE 1588-capable industrial control and test and measurement devices, including future Class A and B LXI devices, the company says. The NI PCI-1588 interface is part of the NI family of synchronization technologies that includes subnanosecond PXI backplane synchronization, multichassis timing interfaces, and standardized software libraries.
Engineers can use the interface’s PTP timestamps to correlate events distributed across an Ethernet network with greater precision and accuracy than available with previous industry standards, NI says. The interface uses RJ-45 Ethernet cabling and can operate as a master or slave clock module. With an onboard FPGA, engineers can adjust the frequency and phase of an onboard IEEE 1588 system timer for time-stamping Ethernet packets. For instance, adjusting the clock frequency to match other clock frequencies improves skew and adjusting the phase improves local PLL clocks and triggers, NI says; it also offers three general-purpose I/O pins and a RTSI bus connection for synchronization with traditional instruments or PLCs and other PCI plug-in devices, respectively. For example, engineers can use the new interface to create a geographically distributed data acquisition system with Ethernet while synchronizing clocks and timestamps to within 200 ns. The interface uses NI-Sync driver software, which offers a common software interface for different synchronization techniques, including IEEE 1588, PXI backplane, and PXI multichassis synchronization.
IEEE 1588 PTP, approved in 2002, provides a standard method to synchronize devices on a network with submicrosecond precision. The protocol synchronizes local clocks to a master clock ensuring that triggers, events and timestamps in all devices use the same time base. IEEE 1588 is optimized for well-defined distributed systems, minimal use of network bandwidth and low processing overhead. The standard has gained acceptance in the industrial automation market, NI says, and is now expanding into the test and measurement and communications markets.
For more from Control Engineering about IEEE 1588, see “Ethernet hits big time…”
—Mark T. Hoske, Control Engineering , MHoske@cfemedia.com