Instrumented Systems

About Instrumented System

A safety instrumented system (SIS) automatically takes action to maintain or restore a plant to a safe state when abnormal conditions occur. The SIS can perform one or more functions to protect against various process hazards. Each SIS function consists of three functions:
  • Sensor: Monitors the process to detect abnormal conditions (for example, a pressure sensor).
  • Logic device: Receives signals from the sensor, evaluates if the condition is hazardous, and sends a signal to take appropriate action.
  • Final control device: Receives the signal from the logic device and implements the appropriate action in the plant (for example, opening or closing a valve, shutting down a pump).

In APM, an Instrumented System represent an SIS. You can create an Instrumented System and link to an existing SIL analysis. Linking a SIL analysis automatically links the loops and associated components. The following diagram shows the Instrumented System in the SIS module, providing a visual representation that helps analysts view the system and related information, such as proof test tasks, proof test events, and SIL levels.



Access an Instrumented System

Procedure

  1. Access the SIS Management Overview page.
    Tip: You can also access the SIS Management Overview page for a selected hierarchy level.
  2. In the workspace, select .
    The Safety Instrumented System page appears, displaying a list of Instrumented Systems.
  3. In the INSTRUMENTED SYSTEM ID column, select the Instrumented System that you want to access.
    The Instrumented System datasheet appears in the Details section of the workspace.
  4. If needed, modify values in the available fields.
    Note: You cannot modify values in the SIL Analysis ID and Asset ID fields after you save the record.
  5. Select .
    The Instrumented System is modified.

Create an Instrumented System

Procedure

  1. Access the SIS Management Overview page.
    Tip: You can also access the SIS Management Overview page for a selected hierarchy level.
  2. In the workspace, select .
    The Safety Instrumented System page appears, displaying a list of Instrumented Systems.
  3. Select .
    The Create Safety Instrumented System window appears.
  4. Enter values in the available fields.
    Note: You cannot modify values in the SIL Analysis ID and Asset ID fields after you save the record.
  5. Select Save.
    The Instrumented System is created.