====Connecting a Model to Data====

The [[AddInput]] command has an optional third parameter that controls where it gets its data from.

If left **None**, it will simply wait for the data to be directly updated by the user, usually through [[OPC-UA]].

If given a string, it can link a couple of different data sources.

===Internal References (#)===

If the path starts with '#', it's an //internal reference// - this means that it's a [[data points|data point]] read out of a different model.

These have a format of **#**//<model name>//**.**//<point name>//

If you needed to access the remaining tank volume (from our [[creating_a_model_in_python|example]]), you could do that by giving your model an [[input|input]] like the one below...

<code>
TankVol = mod.AddInput("Remaining Tank Volume",50,"#Tank.Volume")
</code>

===External References===

If the path starts any other characters than those show above, it's an //ARDI reference// - this means that it's a [[data points|data point]] read from the live value of an asset and property in ARDI.

These have a format of //<model name>//**.**//<point name>//

If you wanted to read the tank level in our [[creating_a_model_in_python|example]] from live data, you'd change the AddInput line to the one below (assuming the ARDI asset is named 'Water Storage Tank' and the property is 'Level'...

<code>
LevelPerc = mod.AddInput("Tank Level Perc",50,"Water Storage Tank.Level")
</code>

[[Reverse-Engineering with Goalseek]]