Linear Assets (9) – Meters

This article returns to the Assets application to see how meters are supported on Linear Assets.

Assets Applications – Meters Tab

A continuous meter on a linear asset, for example a count of the number of accidents, or traffic volume must be placed at a measure along the linear asset. For gauge or characteristic meters, the measure along the linear asset can be added at the point in time the measurement is recorded, it needn’t be defined ahead of time on the asset meter record, but it can be.

The meter name on an asset record is unique, you cannot have two or more meters with a meter name of NOACCID – No of Accidents. If you want to count the accidents at different parts of the linear asset you will need several meters with different names NOACCID01, NOACCID02, etc.

In this example for linear asset I-95N I’ve created four continuous meters NOACCID01 through to NOACCID04 and attached them to various segments of the linear asset. For simplicity I’ve added them in 30-mile segments with the NOACCID04 being the remaining segment from mile post MP 90 to the end of the linear asset. The positioning of the meters may correspond with county boundaries, or the recognised parts of the highway around a city. 

As you are using generic meter names which won’t mean anything in the context of the linear asset then use the Remarks field as a meter label to describe where on the linear asset the meter is recording its values. The Remarks attribute has a long description and the button used to edit/view the long description can be easily added with configuration.

At the bottom of the Meters tab is the familiar Linear Segment Details section which allows you to position the linear segment in absolute measures or with offsets from reference points. For the first linear segment it goes from the start of the linear asset at measurement 0.00 to Reference Point MP 30 at 30.00 MILES.

A meter can also exist at a fixed point along the linear asset. I’ve added four Average Speed Meters of type GAUGE, AVSPEED01 through AVSPEED04.

Each of these asset meters exist at a point, the first for AVSPEED01 exists at the Reference Point MP 20.

Assets Application – Enter Meter Readings

In the Assets application the action Enter Meter Readings will allow new meter readings to be entered. For linear asset I-95N the AVSPEED01 Meter of type Gauge is given a meter reading of 42.50 mph at 28/02/22 11:00.

Scrolling further down the dialog there is the Linear Segment Details section. If you look closely the fields are modifiable, I’ll be returning to this point. 

Similarly, meter readings can be entered for Continuous meters, in this case we have incremented the meter NOACCID01 – Number of Accidents 01, by one, there was an accident at 09:22 this morning 28/02/22.

Assets Application – Manage Meter Reading History

The action Manage Meter Reading History also shows the Linear Segment Details. For Continuous Meter Readings you can modify the meter reading value using the Modified Delta field, but you cannot modify any of the fields in the Linear Segment Details section.

For Characteristic and Gauge Meter Readings there is no ability to change the measurement or observation in the Assets application, but you can do this in the Condition Monitoring application. The table details shows where on the linear asset the meter reading was taken.

For Continuous Meters the meter reading is held in the METERREADING table which has been extended with the linear measurement fields. Therefore, if the Asset Meter was moved to a new position along the linear asset, you would still know historically from where the meter reading had previously been taken.

For Characteristic and Gauge Meters the meter reading is held in the MEASUREMENT table which has also been extended with the linear measurement fields. You would similarly know from where the measurement was taken if the asset meter is moved to a new position along the linear asset.

Earlier we said that we would return to the Enter Meter Readings dialog. When entering two additional accidents for the NOACCID01 – Number of Accidents 01 meter, the Delta means that the New Reading will be added to the previous reading, we have modified the Start and End Measure indicating a point along the linear asset where the accident took place. We used the Mile Post MP 20 and an offset of 2,042 FEET, the Start/End Measure is calculated at 20.39 miles from the start of I-95N. 

Therefore, you can use Continuous meters as if they are either fixed in position, or floating, when you add the meter value you are entering the position along the linear asset where the meter value was recorded. But remember, you can only modify the reading value and not reposition where in the linear asset it was recorded. 

The same applies to Gauge and Characteristic meters, the position where the measurement or observation is made can be changed as you are taking the reading.

Preventive Maintenance – Meter Selection

In the article Linear Assets (7) – Routes and PMs, I indicated another linear feature of the Preventive Maintenance application. The selection of the meter on a PM must be within the scope of the linear segment that is referenced on the PM. For example, a PM between reference points MP 30 and MP 40 cannot select a meter that is measuring the flow of traffic at 25.00 miles, but it would be able to do so for a meter that is measuring the flow of traffic at 35.00 miles. The meter point on the linear asset must be within the linear segment of the PM record.

For a new PM, 1032 – Linear Asset – PM Meter Selection, which is against linear asset I-95N, when you create a Meter Based Frequency record there appears to be no restriction on the continuous meters you can select.

This is because there is no restriction added to the Linear Segment Details on the PM record. When you reference a linear asset the Start Measure and End Measure will be set to the Start/End of the linear asset, in this case 0.00 and 109.70.

I’ve now restricted the Start Measure to the Reference Point MP 20 at 20.00 miles and the End Measure to the Reference Point MP 30 at 30.00 miles.

Now the meters displayed in the Select Value have been restricted to those meters that exist between 20.00 and 30.00 miles, i.e., the meter NOACCID01. Notice that while the PM may be restricted between two measures, it does not mean that the meter must be aligned to those measures, or vice versa. The meter NOACCID01 is from 0.00 to 30.00 miles, which means it is valid in the linear segment on the PM between 20.00 and 30.00 miles. In a real-world scenario you would align the PM linear segment to the asset meter if this were based on a linear segment rather than a point.

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