Logic solvers have the ability to record sequence of events (SOE) messages in Event Chronicle of Process History View. The event messages are created automatically when events occur in certain function blocks used in SIS modules. No special configuration is required for this to happen. The resolution for time stamping the events is the logic solver scan rate.
The Discrete Voter (LSDVTR) function block creates an event message whenever the value of any of its input parameters changes state. This essentially provides SOE detection for discrete input channels at 50 ms.
The Analog Voter (LSAVTR) function block creates an event message whenever the value of any of its input parameters causes the vote to trip on that input to change, that is, TRIP_VOTE_INn to change state. This essentially provides SOE detection at 50 ms for analog input channels as the value crosses the trip limit.
The Cause and Effect Matrix (LSCEM) function block provides first-out trapping for each Effect output. An event message is created when the value of FIRST_OUTn transitions between zero and non-zero. The set event message shows the Cause input(s) active at the time of the event.
Events are stored in the Event Chronicle with a resolution of 1 ms.