Calculating Equipment Run Hours by Signal From Condition

[Morgan Bowling]

Overview:  

This technique example explores two methods for assessing equipment operating conditions per unit of time (i.e. total operating hours per week in this example) using Signal from Conditions (Presented as a Bar Graph) and Histogram.  The Signal from Condition approach transforms a condition into a new signal using an equation or statistical function (in this case we will use an equation and the “TotalDuration” function). The approach using the Histogram tool allows transforming a signal into a "value" domain.  For example, for a given segment of time, plot the distribution of values.  For these examples, we will use “Compressor Power (Area A)” from the Seeq demo data and asset framework, which has routine ON/OFF operating cycles.  

The objective in this example is to create Derived Data signals to indicate when a compressor is running and calculate operating hours per week.  The signals are then presented in two formats - bar graph and histogram.  

Applications:  

Similar types of duration analysis of signals from conditions can add value for Seeq users in comparative analysis for batch processes, calculating and monitoring equipment operating hours and tracking target operating envelope deviations.  

Workflow:

1. Add target signal --Find and add the target signal.  In this analysis we will use Compressor Power (Area A)

2.  Complete a Value Search to determine when the equipment is running.  In this example, I searched the compressor power signal for when it is above 5 kW which indicates it is running. 

 3. Using Periodic Condition, create a Weekly Signal.  This will be used in our Signal from condition Calculation

4.  Create a Signal from Condition.  Create a new signal Compressor Run Hours Per Week using Signal from Condition Tool.  

 

5.  Plot the Signal from Condition as a Bar Graph -- in order to show the derived signal for Compressor Run Hours Per Week as a bar graph, simply click the Customize button in the Details Pane and select the Bar Chart Icon under the Samples column.  The result is shown below.  Each bar represents the total operating hours of the compressor each week. 

 

6. Histogram Aggregated by Calendar Week- The Histogram Tool can also be used to generate a similar graphical analysis for Compressor Run Hours per Week.  However, this tool is currently applicable for performing statistical functions on signals.  In this example, we have created a Histogram, Avg Compressor Run Hours per Week, which calculates the average value of the derived-signal, Compressor Run Hours per Week, aggregated by calendar week (Week of Year).  The Bar Graph and Histogram are shown on the same display below.