Analog Offset Percent Transformation
The analog offset percent transformation, similar to the analog offset value, analyzes how far the Input Value deviates from ideal (see Analog Offset Value). However, instead of using fixed values for the offsets, they are calculated based on a percentage of the Setpoint. The Offset Percent is the percentage the Input Value is over the Setpoint. There are five possible states: High Trip Offset, Low Trip Offset, High Reset Offset, Low Reset Offset, and Associated Setpoint Value. The High Trip Offset and Low Trip Offset states can be used to trigger either an alarm or an event. See Alarms and Events to determine which is most appropriate.
An alarm Delay time can be utilized in situations where an immediate alarm response might possibly generate false or nuisance alarms (e.g. high amps during motor startup period). The Delay Color is assigned to the tag during this delay timeout period, letting operators that an alarm condition exists, but it hasn't yet existed long enough to actually trigger the alarm.
The High Trip Offset % is triggered if the Input Value is greater than or equal to the Setpoint + Setpoint * High Trip Offset %. For example, if the Setpoint is 50 and the High Trip Offset % is 66, then the colors and alarm state of the High Trip Offset % will be applied when the Input Value is greater than or equal to 83 (50 + 50*0.66).
The Low Trip Offset % state is activated if the Input Value is less than or equal to the Setpoint - Setpoint * Low Trip Offset %. For example, if the Setpoint is 50 and the Low Trip Offset % of 66 and a Setpoint of 50 would cause the colors and alarm state of the Low Trip Offset % to be applied if the Input Value is less than or equal to 17 (50 - 50*0.66).
The High Reset Offset and Low Reset Offset represent values based on a percentage in between the High Trip Offset and Low Trip Offset values.These values are used to trigger a change of color to indicate a pre-alarm condition and also function as the value required for reseting a previously trigger alarm. The difference between the trip and reset values is the alarm deadband.
The Associated Setpoint Value sets the color of the tag if the Input Value is within the High Reset Offset and Low Reset Offset values. For example, if the High Reset Offset = 1 and the Low Reset Offset = 1, and the Setpoint = 45, the tag will display the color of the Associated Setpoint Value when the Input Value is between 44° and 46°.