Glossary Updates12 new terms added to the glossaries · October 2, 2026, 22:44 CEST
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Glossary · Industrial communication

Precision Time Protocol (PTP)

Also known as: PTP, IEEE 1588

German: Precision Time Protocol (PTP)

In networking, the Precision Time Protocol (PTP) is the clock synchronization protocol defined in IEEE 1588 that can synchronize clocks in a local network to sub-microsecond accuracy, using hardware timestamping and network components that compensate their own delays.

  • Industrial communication
  • Standards

In one sentence

PTP (IEEE 1588) synchronizes clocks in local networks to sub-microsecond accuracy using hardware timestamping.

Example

Distributed I/O modules timestamp input edges using PTP time, so the controller knows the order of events that happened microseconds apart on different modules.

How it applies

  • Engineering: A grandmaster clock is selected automatically by the best master clock algorithm. Boundary clocks and transparent clocks in switches are needed to reach high accuracy; ordinary switches degrade it.
  • Profiles: Industry profiles adapt IEEE 1588, for example gPTP (IEEE 802.1AS) for Time-Sensitive Networking (TSN), the power utility profile, or CIP Sync in EtherNet/IP.
  • Operation: Loss of the grandmaster or a change of grandmaster can cause time jumps. Applications should monitor the synchronization state.
  • Documentation: The documentation team states the supported PTP profile, the device's clock role and the achievable accuracy under the stated conditions, and explains what happens when synchronization is lost.

PTP vs. NTP

Network Time Protocol (NTP) reaches millisecond accuracy with software timestamps over any IP network. PTP needs supporting hardware but reaches sub-microsecond accuracy in local networks, which motion control and sequence-of-events recording require.

By knowledge.aitechdoc.world · Published September 26, 2026 · Last reviewed

Source: IEEE 1588-2019, IEEE Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems

Definitions follow the cited standards and specifications. Where a source is a copyrighted publication, such as an ISO, IEC or EN standard, the definition is a close paraphrase, not a verbatim quotation, so as not to infringe copyright. We recommend reading the original publication. The sections “How it applies” are editorial commentary by AI TechDoc Blog and are not part of any standard.

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