Concepts Tasks Settings Indicator Value Types An indicator type is an APM object that defines basic settings for groups of indicators. When you create an individual indicator or indicator template, you must select its indicator type. The indicator’s value type and unit of measure categories always come from the indicator type. Each indicator type has one of four value categories that describe how an indicator reading is obtained or represented: • Descriptive – Asset condition is described using a qualitative value, for example, New, Slightly worn, and Worn • Numeric – Asset condition is represented by a number with a unit of measure. Examples are pressure and flow. Calculated and performance indicators are also numeric indicators • Cumulative – Readings track a value that changes over time, such as an odometer. Examples are operating hours, mileage, and fuel consumption • Rule-based – Indicator readings are either “true” or “not true”, based on a combination of factors, usually readings from other indicators Indicator types ensure that the correct value and unit of measure categories are used for individual indicators. For example, if you create a “mileage” indicator type and select “miles” as the unit of measure, users can only create mileage indicators with length measurements. APM prevents users from creating a “mileage” indicator that has readings in gallons. However, a user could create a “mileage” indicator that collects readings in kilometers. In addition, because mileage is a cumulative value type, users cannot change the value type in mileage indicators to descriptive. More specific indicator information, such as the list of possible values for descriptive indicators, is defined on the indicator template or on the indicator itself. This is so that you can use the same indicator type for different kinds of equipment. Rules for rule-based indicators and calculations for calculated indicators are also defined on the indicator template or on the indicator itself. To create an indicator type for calculated or performance indicators, select the numeric value type. Cumulative Indicators An indicator is cumulative if it tracks a value that increases over time, such as an odometer. The current reading on a cumulative indicator is normally either the same as, or higher than, the previous reading. You can collect readings for a cumulative indicator in one of two ways: as an accumulated value (the value over the lifetime of the indicator) or as a consumed value (the increase since the last reading). For example, an odometer tracks the total number of miles that a vehicle has traveled over its lifetime. This is an accumulated value. When you enter a reading for an accumulated indicator, APM updates the indicator with the new reading. If the old life-to-date value was 40,000 miles and the new reading is 45,000 miles, the current life-to-date value is 45,000 miles. On the other hand, you could have an indicator that keeps track of the total number of gallons of gas consumed over a period of time. In this case, you would enter the number of gallons that have been used since the last entry. This is a consumed value. When you enter a consumed value, APM adds the new entry to the previous life-to-date. For example, if the old life-to-date value is 445 gallons and the new reading is 22 gallons, the current life-to-date value is 467 gallons. If you use cumulative indicators in triggering rules, you can set up early warning states for them. For example, you could create a triggering rule that says “trigger every 5000 miles, with early warning 500 miles in advance.” To do this, you must add a daily average calculation to the indicator setup. Cumulative indicators can be collected manually or by an online data collection device. You can also set up cumulative indicators to “cascade,” or send their readings to indicators on other assets. Numeric Indicators An indicator is numeric if it records any value within a finite or infinite interval. For example, an indicator that measures temperature or pressure is numeric. Numeric values can go up and down over time. Today’s reading might be either higher or lower than yesterday’s reading. You can count, order, and measure numeric data. You can set up states and alarms for numeric indicators. Indicator states and alarms can provide additional information to maintenance staff about the meaning of the current value of the indicator. Numeric indicators can be collected manually or by an online data collection device. You can also create indicators that generate calculated readings based on the readings of other numeric indicators. Measurement points are supported for manually-entered numeric indicators. Measuring the condition of certain assets such as piping requires taking two or more measurements to arrive at a reliable reading for the indicator. In the case of an indicator that measures the wall thickness of a pipe, four to eight measurements are commonly needed at different locations around the circumference of the pipe. The location on the asset at which measurements are taken is referred to as the Measurement Location, while the points around the asset where the individual readings are taken are called Measurement Points. Once the values for each of the points is recorded, they can be aggregated to derive a value for the Measurement Location. For example, the lowest value might be selected or the average value. Numeric indicators can also be used to track degradation rates on assets. The degradation rate is used to determine the remaining life (time), remaining degradation allowance (for example, thickness), end-of-life date, and next inspection date for the asset. Descriptive Indicators An indicator is descriptive if it has a distinct set of qualitative values that can be detected but cannot be measured in numbers. For example, if you have an indicator that measures tire condition, a list of possible values for the condition of the tires could be “Good Condition,” “Slightly Worn,” or “Threadbare.” You can select an alarm type (such as “Warning” or “Critical”) for possible values. Rule-based Indicators A rule-based indicator is an indicator whose current state is determined by a rule rather than by a direct reading. The rule is made up of clauses based on the current state of other indicators that, when considered together, can indicate the existence of a problem. APM uses “and/or” logic to evaluate the rule clauses that make up each rule. For example, consider an indicator on your vintage car called “Service Engine Soon.” The purpose of this indicator is to let you know that your car engine is due for a tune-up. The indicator comes on when a certain number of conditions that your car measures on a regular basis exist together. For instance, the indicator light might come on if all of the following conditions are true: • The car’s exhaust emissions are measured to be higher than normal • AND the suspended particles in the engine oil are over a specified amount • AND the car’s miles-per-gallon ratio is below normal APM evaluates the indicator rule whenever a reading is entered for any of the indicators named in the rule. When the rule is logically true, the rule-based indicator goes from being in a normal state to being in an alarm state. The severity of the alarm that gets raised depends on what is defined for the indicator. For example, in the previous example, the alarm might be a simple warning to take the car in for service. You can prevent APM from evaluating a triggering rule if one or more of the contributing indicator readings are outdated. For example, you can say that all of the indicator readings included in the rule must have been collected within one day of each other. This is called the “required proximity” of the indicator readings. Whenever an indicator reading is entered for an indicator that is included in the rule, APM records a reading for the rule-based indicator. The reading includes the date and time, if the alarm was triggered, and information as to why it was triggered. This includes information about the states of all the indicators that were used in the rule. If the indicator readings that contributed to the rule were collected on a checksheet or on a work order task, the resulting rule-based indicator reading is also shown on the checksheet or work order task.
