Understand pump Line Blockage states
- Last UpdatedApr 24, 2025
- 3 minute read
Each pump that is configured in a Flow Network with a Pump Blocked rule will automatically be monitored for blockages and shut down if a Shutdown Sequence or a Point of Interest (POI) has been configured for it. For more information on pump configuration, refer to AVEVA Pipeline Operations for Liquids Administrator documentation.
Pumps monitored by Line Blockage will be in a specific Line Blockage state that determines if and when a shutdown is required. The following state diagram outlines the different states that a pump can be in and how a pump can enter or leave those states. Line Blockage states are reduced to the binary Blocked or Not Blocked indication for Controllers.
|
State Name |
State Description |
|---|---|
|
Not Blocked |
Not Blocked is the default state for a pump and indicates that the pump is not blocked based on the blocked rule configured by the Administrator. Both stops and starts can be performed by you without warnings or shutdowns occurring. When a pump enters a Not Blocked state, any queued automatic shutdowns will be canceled. |
|
Pump Shutdown Sent |
Pump Shutdown Sent indicates that the Line Blockage application wants to shut down the pump. This state is most commonly entered when a pump becomes blocked due to the unexpected closure of a valve. There may be a delay configured by the Administrator that delays the shutdown command being executed. The length of this delay may depend on if the pump is either blocked by a valve that is transitioning to closed, or by a valve in a full closed, based on Administrator configuration. Line blockage will remain in this state until the shutdown procedure is complete (via an action sequence). If the pump fails to shut down, Line Blockage will retry attempting to shut down the pump until it leaves a running state. If you attempt to start a pump in this state, a warning will appear. When a pump shutdown occurs, the pump's protected location shutdown sequence will also be executed if the pump is running. |
|
Pump Blocked and Shutdown |
Pump Blocked and Shutdown indicates that the pump is blocked and has been shut down successfully. Line Blockage will take no action unless the state of the pump changes (such as the pump starting unexpectedly) or the blocked state changes. Line Blockage will not cancel any pending shutdowns in this state as this state can only be entered when all shutdowns have been successfully completed. |
|
Pump Blocked and Running |
Pump Blocked and Running is a special override state that can only be entered by manually starting a pump from a blocked state and overriding the warning that the pump is currently considered blocked. Line Blockage will not attempt to shutdown a pump in this state as it treats the override command as intentional. This state can only be left by either the pump becoming unblocked or the pump shutting down. |
|
Blocking Valve-User Commanded Closure |
Blocking Valve-User Commanded Closure is an action state that is initiated by you closing a valve that the pump requires open to remain unblocked. When this state occurs, you are notified that the pump will be blocked, and the shutdown procedure (via an action sequence) is initiated immediately prior to the valve closure command being sent. Line Blockage then allows a configurable period of time to expire for the pump to successfully shut down. If the pump fails to enter a stopped state within this timeout, the pump will be treated as if an unexpected start had occurred, resulting in another shutdown attempt. |
|
Valve Reversal Command Sent
|
A pump command reversal has been sent to the pump (which reverses the pump state). |