Sercos telegrams contain a Sercos header and a data field embedded in the Ethernet frame (see image below). The Sercos header describes which phase the network is in and the position of the MDT and AT telegrams in the communication cycle. The MDT and AT data fields consist of three areas:
- hot plug field: exchanges data with slaves that have been added to the network while the operation is running.
- service channel field: total number of communication channels that exchange acyclic data between master and slaves.
- real-time data field: is used to create acyclic, cyclic or clock-synchronous connections, and so also real-time communication between any devices in the Sercos network.
Sercos has a clear and robust data structure. This increases operational reliability and simplifies application development. The network status is always clear and entirely transparent. I can make diagnoses of my plant on each network node with current Ethernet diagnosis tools.