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kroberts-31-Visitor
1-Visitor
Nov 26, 2014 4:40 PM UTC
Solved

Error Plotting a Function

Hi

I am fairly new to mathcad and I'm having a problem creating a graph of an equation, which describes the transient behaviour of the torque generated by a moter during a fault condition. The datasheet where the equation comes from states that the maximum value (-295.4) occurs at t=0.016s and so I have been able to check that the equation is giving the correct answer for a single value of t.

I now want to create a graph of the function, but when I try to do so, I get an error stating "Plotting failed. Replace complex values and NaNs by real numbers".

Can anyone tell me why this is going wrong? I have tried it with and without units; using t and t1 as the argument.

Thanks

Ken

My Mathcad Prime 3 worksheet is attached.

RichardJAnswer
19-Tanzanite
Nov 26, 2014 5:46 PM UTC

That's a very misleading error message. You have inadvertently created a function, D(). Insert a multiplication operator so that you have D*(), and it works fine.

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4 replies

RichardJ19-TanzaniteAnswer
19-Tanzanite
Nov 26, 2014 5:46 PM UTC

That's a very misleading error message. You have inadvertently created a function, D(). Insert a multiplication operator so that you have D*(), and it works fine.

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ValeryOchkov24-Ruby IV
24-Ruby IV
Nov 26, 2014 7:49 PM UTC

Richard Jackson wrote:

That's a very misleading error message. You have inadvertently created a function, D(). Insert a multiplication operator so that you have D*(), and it works fine.

See please the Ward # 17 in the Mathcad Mad House http://communities.ptc.com/message/178791

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Werner_E
Werner_E25-Diamond I
25-Diamond I
Nov 26, 2014 5:48 PM UTC

Have you ever tried to evaluate m4(0.01 s)= ore something like that? You get the error "This value must be a function" and if you trace back that error (calculation ribbon) you land in the definition of m4() at D. You typed D(...) instead of D*(...) and so you are calling a nonexistent function D(). Add the multiplication sign between D and the parenthesis and your sheet works as expected.

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kroberts-31-VisitorAuthor
1-Visitor
Nov 27, 2014 8:37 AM UTC

Thanks everyone. I guessed it was going to be something simple.

Ken

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