SIS function blocks > SIS Advanced Function Blocks > Logic Solver Effect function block

Logic Solver Effect function alarm detection

The runtime bitstring parameter EFFECT_ALERTS, summarizes the block's error conditions. EFFECT_ALERTS has four bits that indicate alarm conditions:
  • Forced: the logic sets this bit when the block is being forced either to Normal or Tripped. The term forced here refers to any time when the normal operation of the block is being overridden. Each input on the block has an ENABLE parameter that can be manipulated by user configuration. If the user configuration effectively forces the block by disabling an input, this is not considered forced with regard to the EFFECT_ALERTS parameter. In these cases, the block sets the Inhibited bit instead. The Forced bit is only set when you set FORCE_EFFECT to Force To Normal or Force To Tripped.

    The Forced alert rolls up to a bit in SIF_ALERTS module parameter.

  • Trip: the logic sets this bit whenever the block is not in the Normal state due either to the inputs causing a trip or a forced trip. The Forced alert rolls up to a bit in the SIF_ALERTS module parameter.
  • Inhibited: the logic sets this bit if there are not enough eligible inputs to trip the block. An input is eligible if it is enabled and its status is anything other than BadNotConnected. If the INPUT_OPT parameter is set to Any, then at least one input must be eligible. If it is set to All, all inputs must be eligible. The Inhibited alert rolls up to a bit in the SIF_ALERTS module parameter.
  • Reminder: the logic sets this bit if the block is being forced to normal and the value of FORCE_TIMER is less than the value of REMINDER_TIME. This is used to alert the user that the force will be removed when the timer reaches 0 (unless FORCE_OPTS is set to Force timeout for indication only) . The Reminder alert rolls up to a bit in the SIF_ALERTS module parameter.

The configuration engineer may decide not to provide alarms for trip conditions, preferring to do so for trip demand conditions detected in the blocks that feed into the Effect block. This can be done by setting the relevant bits in REPORT_OPTS to True. This prevents the rollup of bits in EFFECT_ALERTS.