Alarms settings

Introduction

This section describes the Alarms settings which are available in the Instructions dialog box in the System Control module.

Note: How to open and use the Instructions dialog box is described in The Instructions dialog box.
Alarm and Warning limits

The Alarms settings define

  • upper and lower warning limits

  • upper and lower alarm limits

for process monitor signals.

Alarm limits

If the signal exceeds the Alarm limits

  • an alarm sounds

  • an alarm message is displayed

  • the process is paused, that is the method execution is suspended and all pumps are stopped.

Warning limits

If the signal exceeds the Warning limits a warning message is issued without interrupting the process.

Messages are displayed on all stations

Alarm and warning messages are displayed on all stations with a connection to the system concerned, regardless of the identity and access rights of the current user.

Alarms and warnings can only be acknowledged from the control mode connection.

Messages are color coded

Alarms and warnings are displayed in the Logbook pane of the System Control module with different colors, see the illustration below.

  • Warning messages are displayed in orange text.

  • Alarm messages are displayed in red text.

Method instructions and manual instructions override system settings

Limits for certain monitor signals can also be set locally in a method, if allowed by the system strategy. In such case, the method setting (method instruction) overrides the system setting as long as the method is running.

Example: This feature allows for instance the pH warning limit to be set to one value during process operation and another during system cleaning.

Note: Manual instructions also override the system settings.
Settings must be enabled

Alarms are not active unless the mode is set to Enabled. Verify the alarm mode for each instruction line in the list.

Hysteresis

The hysteresis setting (not available for ÄKTAdesign systems) for a warning determines the extent to which the signal can oscillate around the warning limits without re-activating the warning.

After the signal has activated a warning, the warning will not be repeated as long as the signal remains within a window defined by the hysteresis setting above and below the warning limit. This prevents repeated warnings from noisy or oscillating signals close to the warning boundary. See the illustration below.

Note: Hysteresis is only relevant for warnings, since an alarm puts the system in Pause at the first alarm.

2005-06-15