Ethernet Time Synchronization
Time Synchronization over Ethernet is used to set information, statuses and occurring events within a network into the same time base and chronological reference. To achieve this and to hold and synchronize different systems plug & play in the same system time base b-plus is offering a Cluster Time Synchronization Service (CTSS) bundle based on IEEE 802.1AS-2011 (profile of IEEE 1588). As a result this allows to bring data from various times in such synchronized systems with an accuracy of +/-500ns in direct relation. See more details about this solution below.
Because of the wide range of data and the need to validate various ECUs currently a number of computers are used in parallel. The challenge for the so called fusion platforms is that those computer systems need to be set in a temporal correlation. Based on the Cluster Time Sync Services (CTSS) from b-plus every computer can be set with the same synchronized time base. Consequently the data arising from the various systems can now be put in in direct time relation with each other. This is essential prerequisite for the data fusion process.
b-plus offers a system service that can automatically be integrated into the network via the IEEE 802.1AS protocol and a specially modified network card. This service sends periodically the central time of the grandmaster clock to every participant. Time delays of cable length and Ethernet switches are taken into account with this transfer and are compensated accordingly. Additionally frequency errors produced by inaccurate clocks are corrected within the individual nodes. This solution reaches an accuracy of +/-500ns.
Ethernet packets which are communicated in this network are marked with a time synchronized time stamp. This time stamp information is used to bring data information into a chronological correlation. To achieve this b-plus is offering a bundle that consists of a PCIe network card together with an operating system service driver for Windows. Beyond that, this same concept is used as a basic functionality in every b-plus standard product equipped with IEEE 802.1AS (profile IEEE 1588). Consequently every b-plus standard product could be the center of a time synchronized network.
This procedure is especially used for the data acquisition in distributed systems where it is important to analyze the data out of a subsequent fusion process. With this data base it is possible to replay the data just is the same time relation they were generated. This is especially necessary for Hardware in the Loop (HIL) systems. After all the customer receives a functional solution without the need to acquire expensive know-how.