We've created a simple automated incubator application using Components and added a user interface with Visual Controls. Now we want to add functionality to our application by adding data acquisition capability; we want a log of the temperature in the incubator and the dates and times when the heater was actually turned on.

To do this we will use the Data Logger Component. The Data Logger lets us record the values of any other Component by adding that Component as a Source to the Data Logger. The Data Logger's Visual Control is called the Strip Chart. It displays the logged data in graphical format and allows you to control the behavior of the Data Logger itself.

To start, we create the Data Logger Component itself. Do this by dragging and dropping the Data Logger icon onto the Component ListView.

The Data Logger's Property Sheet appears automatically. We use it to tell the Data Logger what data to log and how often.

First, we select the Component sources that we want to monitor and record. Since we want to keep a log of temperature changes, we'll need to log the "Incubator" Converter Component. Using the drop-down boxes, we'll select it and click Add.... This sets "Incubator" as source of the Data Logger.

We also want to log the activity of the heater. To do so we'll also add the "Heater Control" Digital Output Agent as a source. Now the Data Logger is configured to periodically record the values of these two Components.

Next we need to reserve some space (memory) for the Data Logger to store its logged data. To do that we will need to know how many samples we need as well as how often we want to sample. We will determine those next as well.