The List Management (LM) module is more advanced than any other shelving tool on the market. It not only allows operators to shelve nuisance alarms, but also can shelve stale standing alarms automatically. LM offers the ability to restrict critical alarms from being shelved and can be set to re-enable after a set period of time or if the alarm is inactive. With the ability to restrict which alarms can be shelved, a reminder that the operator has alarms shelved and the ability for alarms to automatically un-shelve themselves, LM is the premiere method to allow operators to shelve alarms.
- Exclusion/inclusion list
- Simple right-click entry from Interface Dynamics v3
- Entry validation – verifies roles and restricts multiple entries
- Easy list configuration and management
- Automatic shelving to remove stale alarms from the alarm summary
- Automatic un-shelving based on an alarm being inactive or using a fixed un-shelve timer
- State-based shelving
Though more can be configured, there are three shelving lists that originally exist in LM: short-term, long-term and maintenance. When instruments begin to malfunction and cause the alarm to chatter in and out, the operator can navigate to the LM interface and shelve it on the short or long term shelving list. If the instrument needs maintenance, the operator can shelve it under the maintenance shelving list. The interface shown below allows an operator to easily pick a configured list, specifically which alarm to shelve and whether to shelve immediately or not. After shelving multiple alarms, it is very easy for operators and engineers to keep track of which alarms are shelved by accessing a list of all alarms that are currently shelved in each specific list.
The remind time is the maximum length of time that an alarm will remain shelved independent of the status of the alarm. This is used to un-shelve alarms that are still annunciating when they were expected to clear within a given period of time. The enable time is also known as the clear-to-enable time. This is the continuous period of time that an alarm must be inactive before it will be un-shelved. Operators will use the immediate disable timer for normal operations. The configurable disable time is part of permanent shelving.
Automatic shelving is designed during rationalization and is used to solve stale alarm issues. When alarms are confi gured with automatic shelving, they will annunciate for a set period of time and then automatically shelve themselves for an indefinite period of time. In order for the point to reenable, the process variable must remain in a non-alarmable state for a configurable clear-to-enable time.
Automatic shelving is used on points that the operator’s corrective action does not clear the alarm. This causes alarms to only appear on the operator’s alarm summary as soon as they occur, rather than the entire time they are in the alarm state. Examples would include pump statuses, first outs and some hand switches.