Who applies timestamp to sourceTimestamp parameters?
Posted: 02 Jan 2018, 16:41
Hi,
I'm working in a development of a method for time analysis of OPC UA services which main feature is realize data access in real time (operations like read, write and monitoring).
For this work I'm using the timestamp parameters available in services and shared between client and server in the execution of these services. One of these parameters is the souceTimestamp that is used to reflect the timestamp applied to a data by the data source.
In most of cases the data source is a device like a PLC that in conected to field devices like a sensor, for example (OPC UA Client -> OPC UA Server -> PLC -> Sensor). Considering here that the server is installed in a dedicated hardware separated from PLC.
My question is who applies the timestamp to the data, PLC or sensor?
In the case where the PLC applies the timestamp to the data, in order to determine the moment when the sensor has captured the read value, I have to consider the scan cycle, or am I wrong?
Thank you very much in advance and I'm sorry for any English mistake.
I'm working in a development of a method for time analysis of OPC UA services which main feature is realize data access in real time (operations like read, write and monitoring).
For this work I'm using the timestamp parameters available in services and shared between client and server in the execution of these services. One of these parameters is the souceTimestamp that is used to reflect the timestamp applied to a data by the data source.
In most of cases the data source is a device like a PLC that in conected to field devices like a sensor, for example (OPC UA Client -> OPC UA Server -> PLC -> Sensor). Considering here that the server is installed in a dedicated hardware separated from PLC.
My question is who applies the timestamp to the data, PLC or sensor?
In the case where the PLC applies the timestamp to the data, in order to determine the moment when the sensor has captured the read value, I have to consider the scan cycle, or am I wrong?
Thank you very much in advance and I'm sorry for any English mistake.