Accurate time is something most of us take for granted. With PLCnext Technology, however, precise time synchronization plays an important role in keeping connected industrial devices and applications aligned. A smartphone displays the correct time without requiring the user to configure or regularly correct it. In connected industrial systems, maintaining this level of accuracy across multiple devices is far more complex.

Every device contains an oscillator, usually quartz, that provides its internal clock. Even after that clock has been set, small inaccuracies cause it to drift away from a reference source such as International Atomic Time. Without an appropriate synchronization protocol, affordable device oscillators cannot maintain accurate time over extended periods.

For industrial applications, that difference matters.

Why accurate time matters in industrial systems

High-precision time synchronization is essential when data from distributed devices must be compared or analyzed. Time-series information can only be correlated reliably when every participating device uses a consistent time reference.

Accurate time also supports security-certificate validation and provides reliable timestamps for alarms, events, and device websites. It is therefore important for applications ranging from operational diagnostics to data analysis and artificial intelligence.

The open PLCnext Technology ecosystem has long supported Network Time Protocol, or NTP. This widely used protocol provides synchronization with accuracy in the millisecond range. With the integration of Time-Sensitive Networking standards into PLCnext Technology, users can now also benefit from the more accurate Precision Time Protocol, or PTP.

Greater precision with PTP

PTP enables timestamps across participating devices to remain within a few microseconds of the synchronization source. This level of accuracy makes it possible to arrange distributed events in a high-resolution sequence.

PTP also simplifies configuration. Because the protocol operates directly over Ethernet, users do not need to specify the IP address of a time server. A device can synchronize with an available time source immediately after startup. If a device is replaced or the time server changes, additional configuration is not required.

Connecting different network levels

PLCnext Control controllers can also operate as PTP time gateways. As a result, time information from a higher-level network, such as a production cell, can be passed to a lower-level network, such as an individual manufacturing machine.

This capability is especially useful when the two levels are located on separate networks. At the same time, the application retains visibility through the available system variables.

To deliver this accuracy, the Ethernet infrastructure must support PTP. Compatible switches measure the time required for synchronization telegrams to travel through cables and network components. They then correct these transmission delays.

Because the synchronization telegrams also contain the source time, the receiving equipment can identify the remaining deviation immediately.

A cross-platform approach

PTP is based on the cross-platform IEEE 802.1AS standard. Therefore, an application is not limited to TSN switches from Phoenix Contact. Compatible devices from other manufacturers can also be incorporated into the network.

NTP continues to provide an effective option when millisecond-level accuracy is sufficient. However, PTP offers a major advantage for applications that require precise event ordering and transparent information about synchronization quality.

With PTP integrated into PLCnext Technology, industrial time synchronization can be implemented with greater precision and less configuration effort. Crucially, these advantages can be achieved using the existing hardware of the respective products.

Discover how PLCnext Technology combines openness, flexibility, and advanced industrial networking capabilities.