can u please explain trending a DAT element using TTD logs
I´m not really sure what you are asking for, but here goes anyway. TTD logs are logs that are stored within the Advant controller. Because the controller has a limited amount of memory, and is shared with other database elements and PC-programs, the storage space is limited. TTD logs can be set up as hierarchical logs in order to extend the time span of trend data. TTD logs can also be extended into xA as OPC data logs.
Logging of DAT elements is possible, but you will have to set up a program that writes a true value to the :VALID pin of the DAT database element. You can also just set the :VALID pin to true, but you risk loosing it if you for example suffer a power loss. It´s more common practice to use AIC as type for data that is to be both presented in HMI and as trend data.