Alternating Limit Alarm 
Alternating Limit alarm rules are triggered when multiple points are plotted in a consecutive pattern, alternating up and down anywhere on the chart.
For alarm rule 4, the limit and length values are used for both the upper and lower charts. The data points on the chart are checked for the specified number of alternating points. For alarm rule 4, an alarm is triggered when there are <Limit> number of data points in the <Length> data point string that are alternating up and down. You can also use alarms 30 or 31. The data points could be anywhere in the upper region or lower region or across the center line.
Features
Following are the alarm properties defined for Alternating Limit Alarm:
Alarm Name | Property Name | Parameter | Data Type | Description |
|---|---|---|---|---|
Allow Upper Chart Alternating Limit Alarm | UpperWEAlternatingAlarmEnabled | Boolean | Enables alternate limit alarm for upper chart | |
Allow Lower Chart Alternating Limit Alarm | LowerWEAlternatingAlarmEnabled | Boolean | Enables alternate limit alarm for lower chart | |
Alarm 4 | Limit of Alternating Limit Alarm | WEAlternatingAlarmLimit | Integer | Sets the limits and length values to determine the alarm |
Length of Alternating Limit Alarm | WEAlternatingAlarmLength | Integer | ||
Alarm 30 | Limit of Upper Chart Alternating Limit Alarm | WEUpperChartAlternatingAlarmLimit | Integer | Defines the limit and length to check for alternating points in the upper chart |
Length of Upper Chart Alternating Limit Alarm | WEUpperChartAlternatingAlarmLength | Integer | ||
Alarm 31 | Limit of Lower Chart Alternating Limit Alarm | WELowerChartAlternatingAlarmLimit | Integer | Defines the limit and length to check for alternating points in the lower chart |
Length of Lower Chart Alternating Limit Alarm | WELowerChartAlternatingAlarmLength | Integer |
Example
If you use alarm rule 31 with limit and length as 4 and 5 respectively, the alarm rule 31 is violated when 4 points in a string of 5 adjacent points in the lower chart are alternating above and below the center line. In the below illustration, four points are alternating up and down, and are marked as a rule violation.
Graphical representation of Alternating Limit Alarm:
