plotting issue -this variable is undefined

[Marius_P]

Hello,

I have some difficulties to plot on a XY axes system, the efficiency of a voltage converter. I want to have on the x-ax the output current in Amps, and on the y-ax the result in % for a specific switching frequency value.

The error that I got is related to the fact that the variable from the x-ax is undefined.

Could you help me please to understand what is wrong?

Thank you!

[MartinHanak]

Hi,

you picture contains large white area. Please use Snip&Sketch application to get picture of specific screen area.

Also upload Mathcad file if it is possible.

[Marius_P]

Hello Martin,

Please find attached the capture using snip & sketch tool.

[MartinHanak]

Hi,

also upload Mathcad file if it is possible.

[Werner_E]

Because you are using units on variable "Io" you can't use the quickplot feature of Prime.

You have to define a "Io" as a range to be used for plotting in front of the plot. Something like Io:=0A, 0.1A .. 120A.

[Marius_P]

Hello Werner,

Yes, I noticed that the units have an influence, and I did a small change, please see it attached.

Thank you!

[Werner_E · Accepted solution]

Its not a good idea to omit units as its one of the strengths of Prime to be able to naturally deal with units.

Instead of using Io dimensionless and adding the unit Ampère just when you call the function, you should rather use a range variable with units for Io.

You may also consider formatting the function values as percent instead of multiplying with 100.

For further questions you sure should attach your Prime worksheet (and state which version you are using) instead of posting just pictures.