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MK_91243071-Visitor
1-Visitor
April 12, 2023
Solved

Units are not compatible

  • April 12, 2023
  • 1 reply
  • 2158 views

Hi!

 

I have a very bizarre error that I just can't solve.

 

See the following:

MK_9124307_0-1681291661517.png

This gives me the "units are not compatible error" if I use t_uZkplus.max.

 

If I put the solution for t_uZkplus.max manually in the lower line it works just fine:

MK_9124307_1-1681291735262.png

I really don't understand what is going on here. Does anybody have an idea?

Best answer by Werner_E

Looks indeed strange, but as Fed already wrote, without seeing the sheet itself we can only stab in the dark.

So if possible you should attach the worksheet or a simplified, down-stripped version of it showing the same behaviour.

 

You may use the error tracing - maybe knowing the line in the function u.Zkplus_Int( ) which throws the error can help in finding out what happens.

Werner_E_0-1681306041504.png

 

A significant difference between real Mathcad, where your original file stems from, and Prime is, that Prime is not using SUC (static unit checking. This means the something like 0 + 12 V = 12 V, which works OK in Mathcad, may (must not!) fail in Prime because Prime often needs a unit even if the value is zero.
The converter is not fixing situations like that and it can be quite hard to find these stumbling blocks in a converted sheet.

It doesn't look to me that this could be the cause in your case, but can't say for sure without seeing the sheet.

1 reply

F
Fred_Kohlhepp23-Emerald I
23-Emerald I
April 12, 2023

Without the sheet to investigate, we can only guess.

 

I suspect you have run afoul of the dreaded label issue.  Prime may not always recognize what each .variable unit is.  Check 

Fred_Kohlhepp_0-1681297218872.png

 

M
MK_91243071-VisitorAuthor
1-Visitor
April 12, 2023

Unfortunately it is already labeled as a variable.

 

What is even more weird is the fact that it depends on the value of t_uzkplus.max.

 

As in the opening post it doesn't work if the result is 6.667 ms (well it works with 6.667 ms if I manually copy the result into the function):

MK_9124307_0-1681297523311.png

 

But it does with a different value:

MK_9124307_1-1681297571784.png

 

EDIT: I don't know if it's important but that sheet was converted from an older version of Mathcad where everything worked fine...

 

W
Werner_E25-Diamond IAnswer
25-Diamond I
April 12, 2023

Looks indeed strange, but as Fed already wrote, without seeing the sheet itself we can only stab in the dark.

So if possible you should attach the worksheet or a simplified, down-stripped version of it showing the same behaviour.

 

You may use the error tracing - maybe knowing the line in the function u.Zkplus_Int( ) which throws the error can help in finding out what happens.

Werner_E_0-1681306041504.png

 

A significant difference between real Mathcad, where your original file stems from, and Prime is, that Prime is not using SUC (static unit checking. This means the something like 0 + 12 V = 12 V, which works OK in Mathcad, may (must not!) fail in Prime because Prime often needs a unit even if the value is zero.
The converter is not fixing situations like that and it can be quite hard to find these stumbling blocks in a converted sheet.

It doesn't look to me that this could be the cause in your case, but can't say for sure without seeing the sheet.

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