Excel add-in: the "expr" keyword

A very, very useful feature!

For the model “BLOCK900_DH.ebs”, let’s suppose you want to read the mass flow of the steam entering each of these 3 preheaters into an Ebsilon EbsLink:

The “Traditional” Way

You could get those variables into Excel in the usual manner: double-click one of the steam pipes, then find the Mass FLow… right click… “Copy Variable Definition”. Then do the same for the other two pipes (except do “Append Variable Definition”). Then go to the EbsLink and Insert Variable(s)

That’s a lot of work, and gives you this in Excel:

It’s not really clear what those Steam pipe names are referring to!

The Better Way

Use the “expr” keyword instead of “result”, and type an expression for the things you want to read into Excel:

These expressions use the same syntax as you’d use in a Specification, a Text Field, or within an EbsScript. A key trick is the underscore notation:

._3

This refers to the pipe at Port 3 of the given component. Thus, Preheater_5._3.M is referring to the mass flow of the pipe at Preheater_5’s Port 3 (that is, the steam pipe).

You type these expressions manually. A nice thing is that they are readable — you know exactly what they refer to, unlike Steam_24.M

Note that the Units column is NOT USED! These are free-form expressions, so the Ebsilon Add-in won’t do any processing of Units-of-Measure.

Expressions with calculations

You can do calculations within these expression cells (again, just like you can do in Specifications, Text Fields, and EbsScripts). Here, this single expression cell is getting the Temperature Rise (as a difference of two temperatures) of the Condenser cooling water:

I generally don’t do this. I prefer to extract the values separately, and have Excel formulas do the math. This preserves the “granularity” of the data so I can see the values which are used in the calculation. Feel free to do this however you wish, of course!

Sample File

See the file “EbsLink example.xlsx” on my Ebsilon Tips OneDrive.

---