SIS function blocks > SIS Math Blocks > Logic Solver Calculation function block > Expressions in DeltaV SIS Software > Functions in Logic Solver Expressions

SYSSTAT function

Use the SYSSTAT function to detect the occurrence of a module restart caused by a Switchover, a download or a power failure. Using SYSSTAT you can develop an appropriate restart sequence depending on the circumstances leading to the restart. The $SYSSTAT_OPTS ($SYSSTAT_LS_OPTS for SIS systems) named set is provided to facilitate the use of this function.

On the first execution of the module after a restart event, the SYSSTAT function detects the type(s) of restart that have occurred. At the end of that execution, the restart value is cleared, creating a one-shot event within the module. Unlike the other options, the MyDownload option is not detected on the first download of a new module, but only on subsequent downloads of the module.

The following example expression detects the occurrence of a controller switchover during the subsequent restart of the module.

Example for non-SIS systems:

'OUT1' := sysstat('$sysstat_opts:Switchover')

Syntax:

Example for SIS systems:

'OUT1' := sysstat('$sysstat_ls_opts:Switchover')