IEEE-1588 Standard for a Precision Clock …

[Pages:94]IEEE-1588 Standard for a Precision Clock Synchronization Protocol for Networked

Measurement and Control Systems

-A Tutorial-

John Eidson October 10, 2005 john_eidson@

? Copyright 2005 Agilent Technologies, Inc

Outline

1. General overview of the technology and applications 2. Guide to the standard- a detailed analysis of the

major clauses 3. IEEE 1588 interoperability/conformance topics 4. Implementation topics

Tutorial on IEEE 1588 October 10, 2005

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General Overview of the Technology

a. Purpose b. Status and activities surrounding IEEE 1588 c. Comparison to other protocols

Tutorial on IEEE 1588 October 10, 2005

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The Purpose of IEEE 1588

IEEE 1588 is a protocol designed to synchronize realtime clocks in the nodes of a distributed system that communicate using a network.

NETWORK

Tutorial on IEEE 1588 October 10, 2005

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The Status of IEEE 1588

?Approved by the IEEE-SA Review Committee on September 12, 2002 ?Published as IEEE 1588-2002 on November 8, 2002 ?Available from the IEEE ?Approved as IEC standard IEC 61588 on May 21, 2004 ?Products and installations started appearing in late 2003 ?Conferences on IEEE 1588 held in 2003, 2004, 2005 ?P1588 committee in process of extending the standardtarget completion in late 2006 ?Current information may be found at

Tutorial on IEEE 1588 October 10, 2005

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Comparison to Other Protocols

IEEE-1588 NTP

GPS

TTP

SERCOS

Spatial extent

Communi -cations

A few subnets Network

Wide area Internet

Wide area Satellite

Local bus Local bus Bus or star Bus

Target Sub-

Few

Sub-

Sub-

Sub-

accuracy microsecond milliseconds microsecond microsecond microsecond

Style Resources

Master/slave

Small network message and computation footprint

Peer ensemble

Moderate network and computation footprint

Client/server

Moderate computation footprint

Distributed Moderate

Master/Slave Moderate

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Comparison to Other Protocols (continued)

IEEE 1588 NTP

GPS

Latency

Yes

correction

Yes

Yes

Protocol specifies security

Administration

No (V2 may include security)

Self organizing

Yes

No

Configured N/A

TTP

SERCOS

Configured No

No

No

Configured Configured

Hardware?

For highest accuracy

Update interval ~2 seconds

No

Varies, nominally seconds

RF

Yes

receiver

and

processor

~1 second Every TDMA cycle, ~ms

Yes

Every TDMA cycle, ~ms

Tutorial on IEEE 1588 October 10, 2005

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Comparison to Other Protocols (summary)

IEEE 1588: Target is groups of relatively stable components, locally networked (a few subnets), cooperating on a set of well defined tasks.

NTP: (Network Time Protocol, RFC 1305). Target is autonomous systems widely dispersed on the Internet.

GPS: (Satellite based Global Positioning System of the US Department of Defense): Target is autonomous, widely dispersed systems.

TTP(), SERCOS (IEC 61491): Target is tightly integrated, usually bus or specialized TDMA network based closed systems.

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