Units are not properly converted after symbolic solver

[PH_14387723]

Hello Community, 

Please find the mathcad file in the attached it was developed in PTC9

1.In the following after the symbolic evaluation the units are not simplifying, for instance Ohms*Farads

should be seconds, and Farad * Voltage should be Columbs, but 

2.After Q2 as assigned as the result after the integration, when I try to call on Q2 it cannot be found, can someone please explain?

Thanks

[Werner_E · Accepted solution]

Prime often gets the labels ("Unit", "Variable", "-") wrong when using the symbolics.

You should turn on this option and let the worksheet recalc

Primes symbolics still does not know anything about units (its treats them as unknowns and so can't simplify Ohm*Farad to seconds) but at least it now gets the labels correct (you can see that the units in the symbolic results are now bold blue (which means they are correctly labeled as "Unit") ans so xou can evaluate the expressions numerically without errors.

But I wonder why you would use the symbolics at all and why you are first defining the derivative (I1) just to integrate it a moment later?

Prime 9 sheet attached

[PH_14387723]

Thanks the first solution works,  I will mark it as the solution!

The reason to using symbolics is to generate a generic transfer function!

[Werner_E]

If you are looking for a generic function I would suggest you use the symbolic calculations before you define any numeric values.

You may also turn the expressions into functions of the input values which makes it easier to evaluate them later and maybe compare the results of different input values

[PH_14387723]

The first solution works I will mark as the solution

The reason to use symbolics is to generate a generic transfer function