====Incoming and Outgoing Measurements====

===The Problem===

While most of your instruments //measure// a value, some others //change// the value instead.

For example, the heat-exchanger in an air conditioner or an air-drier often looks like this...

{{ardiadminguide:heat_exchanger.png}}

In this situation, looking at the heat-exchanger in ARDI would only show you the //inlet// temperature - the temperature coming from up-stream. There's two problems with this...

   * The inlet temperature isn't clearly marked as **inlet** - it's simply //temperature//, which is a little confusing
   * Users are going to also want to see the **outlet** temperature too.

===The Solution===

You can use [[references|references]] to solve the problem - in fact, the reference documentation specifically mentions this scenario.

Step by step, you need to....

   * Go to the [[detail_properties|property details]] page for the asset, **B**.
   * [[ardiadminguide:adding_a_reference|Add a reference]] to the down-stream sensor (**C**) temperature, calling it **Outlet Temperature**.
   * Add another reference to the up-stream sensor (**A**) temperature, calling it **Inlet Temperature**.

This not only brings in both temperatures so you can see the performance of the heat-exchanger, but it also labels them appropriately so you can clearly see which is which.