Thursday, July 29, 2010

Deep Dive: What is a Data Point

In Nimbits, everything revolves around a Data Point. A Point represents a single collection of time series data. A single temperature reading and any single value that changes over time.  

Your personal collection of data points are connected to the account you were logged in with when you created them.

To create a new Data Point, simply log into Nimbits and select Green Plus sign in the data point tree. You'll be prompted to give the point a name. When a point is created, it is initialized with a zero value at the time of it's creation UTC.


From there, you can double click on that point to view it's chart, map, gauges and anything else. Also, a drop down menu is available to configure the point's properties.




Here is an overview of some of the more important properties a point can have:


Compression

As a value is recorded into a Data Point, the Compression value is referenced. Nimbits only records changes in values. So if a Data Point has a current value of Zero (0) and a Zero value is recorded, there will not be two zeros in the database, the new value will be ignored since the value has not changed.

If a Data point has a compression setting of 1 (One) and a current value of 3.14 and a new value is entered of 3.5, the value will be ignored. Only values that are higher or lower than the current value +/- the compression setting will be recorded as new values.

A Compression setting of 5 and a current value of 100 will ignore all recorded values  less than 105 and greater than 95.  A if the value 106 is recorded into the same point, future recordings less than 111 and greater than 101 will be ignored.

Alerts

All data points can be configured to send alerts.  Set a high and/or low value in the alert settings and turn the high or low alert on and any recorded value greater than the high alert or lower than the low alert will trigger an email to the owner of that point.

Calculations

When a data point is written to with a new value, the event of recording a value can trigger a calculation. The formulas basic arithmetic will be executed and the resulting value will be recorded into the target point – all compression, alerts and other functionality will then be executed.

A Data Point can be a trigger, parameter or target for a formula.

If a point is a trigger and a new value is written to it (see the record value diagram – the new recording must be outside compression settings etc) the formula assigned to that data point will be executed. Usually, the trigger data point is also the X parameter in the formula.

After the formula executes successfully, the resulting double value is stored in the target point and all Record Value settings are processed (Such as Alerts, Compression etc)

Example
A Point is created that has a temperature of degrees F being record to it. The point is set to be a trigger and is also the X variable in this formula (X-32)*(5/9) which is the formula for converting F to C.

A New Data point is created for storing the result of this formula and is then set as the target for this formula in the F Point’s settings. Now, each time the F point is written to, this formula will be executed using the new value as the X Parameter and the result will be stored in the new C Point.  


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