Concepts Tasks Settings Indicator States and Alarms There are two types of states for an indicator: normal states and alarm states. Alarm states occur when an indicator has a reading that is outside of the defined normal state for the indicator. For example, you might have a temperature indicator with the following states and alarms: States for Engine Coolant Temperature From To Alarm Type High Critical 101º Critical High Alarm 99º 100º Alarm High Warning 95º 98º Warning Normal 85º 94º Low Warning 80º 84º Warning Low Alarm 77º 79º Alarm Low Critical 76º Critical If an indicator reading of 75° is recorded, APM triggers the low critical alarm. You can add states and alarms to numeric, descriptive, calculated, and performance indicators or indicator templates. Descriptive indicators have possible values, which are similar to states, and can also be linked to alarms. Rule-based indicators have only two states: true or false. You can select an alarm to be triggered when APM evaluates the rule as true. For descriptive indicators, you can define the possible values that can be read for the indicator. For example, if you are measuring tire condition on a vehicle, the indicator might have three possible values: Possible values for Tire Condition Normal Slightly worn Threadbare Normal vs. Alarm States There are two types of states for an indicator: normal states and alarm states. An indicator is considered to be in a normal state when the asset is operating as it was intended to in a given context. For example, in the case of the engine coolant temperature indicator, the normal state is when the temperature of the coolant is between 85° and 94°. There is typically one normal state for each indicator. In our example, the other two states identified for the indicator are considered non-normal because the engine coolant is either hotter or cooler than the normal range. The purpose of the alarm indicator state is to raise an alarm to warn the driver that there might be a problem with the engine. Severity of Alarm States Not all alarm states are equally serious. Usually, the more an indicator deviates from the normal range, the more serious or severe the state is considered to be. For example, if the coolant temperature of an engine is only one degree hotter than the normal range, it might only indicate a minor problem. However, a 10 degree higher temperature probably indicates a more serious situation that could result in severe damage to the engine. To tell APM the severity of one alarm state relative to another, you can assign different alarm types to each alarm state. The alarm type describes the severity of the alarm state and ranks it numerically relative to the other states. For instance, the alarm types associated with the states of the engine coolant temperature indicator might look as follows: States for Engine Coolant Temperature From To Alarm Type High Critical 101º Critical High Alarm 99º 100º Alarm High Warning 95º 98º Warning Normal 85º 94º Low Warning 80º 84º Warning Low Alarm 77º 79º Alarm Low Critical 76º Critical The alarm types for the tire condition indicator might look as follows: Possible values for Tire Condition Alarm Types Normal Slightly worn Warning Threadbare Critical
