Alarms are used to give warnings or to stop the program from performing unsafe or undesired operations.
Inserting an Alarm:
An Alarm is added to the program by dragging the alarm icon (in red square) from the toolbox to the program condition component holder, or by right clicking on the holder and “Add Alarm”
An Alarm may also be copied from another alarm (Right-Click, Copy and give new name) in the same program.
The Alarm may also be created by dragging the Alarm icon (Red Square) into the Alarm Holder.
The type of Alarm and other elements are then configured.
Alarm Enabler item types are
- Combined Conditions
- Digital Inputs
- Analog High High Alarms
- Analog High Alarms
- Analog Low Alarms
- Analog Low Low Alarms
- Step Time; Check performed on Step Time elapsing. Also known as Watchdog Time
- Valve Error
- Motor Error
- Unit in Maintenance
- Unit in Manual
- Unit Selected
Alarm may be configured on items being true or false where appropriate.
Items of type chosen are available in the enabler list.
An Alarm may be one of the following;
- Critical alarm.
- Non Critical alarm.
Critical Alarm: This will cause the Program to go into Alarm and Hold. This must be Reset before the Program can Restart.
Non Critical Alarm: This is a Warning, it will not cause the Program to go into Hold. It will be registered at HMI/Scada and must be acknowledged there.
Event: This may be setup for an item to be logged, and will not appear in HMI/Scada
The “Description” tab is used to enter a long description of the alarm for documentation purposes.
Type, Item and Alarm Text configuration
The Alarm is configured by selecting one of the Types above and the particular item from the Drop-Down menu.
A Description and Alarm text is also assigned. The Alarm Text may be the same as the description by clicking the selection.
In the example the Alarm is generated if the Low Level in the Sterilant becomes True. The Alarm is defined as a critical Alarm, so it will cause Program Alarm and Hold states if it occurs in the Steps it is assigned to.
The Short Description is selected to be the Alarm Message text also.
A field for full description of the Alarm is provided also. Text entered here will be used in documentation.
Enabling an Alarm in Program Steps
The Alarm is enabled for required Steps in the ‘Usage in Steps’ Tab.
Here the Steps not using the Alarm are listed on the left and the Steps that the Alarm is enabled in are on the right. An Alarm is added to a Step by clicking on the step in the left hand panel and clicking Add. Also, an Alarm may be removed from a step by clicking on Step in the right hand panel and clicking the Remove button.
Add All and Remove All are provided also,
An Alarm may also be added to a Step in the Step configuration, where there is a tab field for Alarms.