====Count Example: Number of State Changes Per Day====

In this example, we want to know how many times our machine stopped and started every day.

Our machine has a simple 'running' signal that is 0 when the system is off, and 1 when it's on.

===Available Information===

^Asset^Property^Desc^
|Main Machine|Running|A digital value showing if the machine is running|

===Initial Layout===

{{start_counter.png}}

To begin with, we have one [[counter_pivot|Pivot]] node named //Pivot On//, and one [[counter_totaliser|Total Output]] node named //Total//

The output node is fed from an [[ardi_point|ARDI Point]] (a point of data from the field), while the pivot is driven from a [[timing_diff|Time Difference]] node.

===Step 1: Choose the Pivot===

Our first step is to choose //what we are going to pivot on//.

Fortunately, the default should work fine here. Simply choose a date in **YYYY-MM-DD HH:MM:SS** format that you want to use as the 'base' of your day.

For example, if your official 'day' starts at 9:00AM, you might want to use that time as the basis of your days.

To set the name of the node, 

  * Right click on the top-left node, choose Title and type 'Day Number'

===Step 2: Choose the Data to Count===

Next, we need to choose //the data we want to count//.

The counter will increase by 1 every time the incoming data //changes//.

Because this is an enumeration/discrete point of data, we'll replace our **ARDI Point** with an **ARDI Status**.

  * Right-click on the //ARDI Point//, choose 'Remove'
  * Right-click in empty space, choose 'Add', 'ARDI' and 'ARDI Status'
  * Choose **Main Machine.Running** as the property.
  * Connect the output of this new point to the **Counter** node.

{{complete_mode_count.png}}

===Analytic Complete===

And you're done - by pressing **Save and Visualise**, you'll have a simple analytic showing the number of times your machine changed state.

{{pivot_mode_display.png}}

===Doing More===

One issue is that we're counting //all// changes - meaning we're counting every time the machine turns on **and** off. It would be more meaningful to our users if we just counted the times it //switched on//.

We can use the [[counter_ignore|Ignore]] node to ignore transitions from 1 to 0 and only count those from 0 to 1.

  * Right-click an empty area, choose 'Add', 'Count' and 'Ignore'  
  * Drag the //false// output of the ARDI Status node to the 'Active' input of the new Ignore node.

This now tells the algorithm to //ignore// (ie. don't count) any transitions where the running status is 0. In effect, this only counts those movements from 0 to 1, rather than 1 to 0.

{{complete_mode_count_extra.png}}