Suppose you have been using the original default sign convention for recipe blends in your model. The operations would look like this, if you exported them to an SSI (or if you entered them in TABLE 4**.2). The Turbine Fuel (TBN) which is the blend that is made has a negative sign, while the two inputs are positive.

I prefer to set them up the other way, by ticking “Reverse standard recipe sign convention” on the Recipe List panel (RSIGN=1 in TABLE 990.0), so that the consumptions are negative just as they are in process units. By the way, the old convention is going to generate a warning message from release 5.4 in preparation to withdrawing it, so this is a good time to switch them round, if you are stilling using the original sign convention.

Put a “-1” in a convenient cell somewhere, select and copy it.

This trick works with formulae, as well as numbers. Suppose you have a spreadsheet to calculate the limits on crude purchases, based on a standard cargo size and the number of cargos available.

You decide to switch from m3 to ‘000 m3 to improve the scaling of the model, so you want to divide the limits by 1000, which you put in cell J17. While you could use Paste Special to divide the numbers in the Cargo Size column, I want to show you what happens if you copy the division into the Max column.

The Paste puts brackets around the original formulae and adds “/1000” at the end – and unlike doing an edit and copying it down, I didn’t need to worry about any cells with a different formula. Neat!

Thanks to Nacho Gimenez for introducing me to this many years ago when he was working as the GRTMPS model developer at Castellón Refinery.

From Kathy's Desk 25th July 2017.

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