topic Re: How can I have Celcius not Kelvin on the X-axes of Prime plot in Mathcad

How can I have Celcius not Kelvin on the X-axes of Prime plot

ValeryOchkov — Tue, 09 Apr 2019 11:22:11 GMT

Help please - see the attach

Re: How can I have Celcius not Kilvin on the X-axes of Prime plot

Werner_E — Tue, 09 Apr 2019 10:31:15 GMT

Oviously it does not work the way it should (by simply chosing °C in the unit box) so one crude way is to do the conversion manually. Not very satisfying, I guess.

Re: How can I have Celcius not Kilvin on the X-axes of Prime plot

ValeryOchkov — Tue, 09 Apr 2019 11:53:53 GMT

Thanks, Werner!

Same bag:

Re: How can I have Celcius not Kelvin on the X-axes of Prime plot

Fred_Kohlhepp — Tue, 09 Apr 2019 12:10:44 GMT

The Kelvin and Rankine scales are absolute--they both start at absolute zero and are therefore a ratio. Centigrade (Celsius) and Fahrenheit scales have arbitrary (and different) zero reference points. Mathcad has to use functions for that conversion. If you look under units the the ribbon, you can select which units to plot with.

Re: How can I have Celcius not Kelvin on the X-axes of Prime plot

ValeryOchkov — Tue, 09 Apr 2019 12:42:42 GMT

Not all is fine in Mathcad 15 too

Re: How can I have Celcius not Kelvin on the X-axes of Prime plot

Werner_E — Wed, 10 Apr 2019 09:49:04 GMT

Hi Fred!

Think we found a bug in Prime 5!

What you show was exactly what I tried first (and Valery sure did so, too) and it failed because we both used Prime 5.

It works OK in Prime 4 but throws an error in Prime 5!

So the bug was freshly introduced with Prime 5 (and we thought there would be no development of Prime any more 😉

Re: How can I have Celcius not Kelvin on the X-axes of Prime plot

ttokoro — Wed, 10 Apr 2019 11:57:03 GMT

Re: How can I have Celcius not Kelvin on the X-axes of Prime plot

ValeryOchkov — Wed, 10 Apr 2019 12:20:45 GMT

Maple has:

Fahrenheit
Celsius
centigrade
Reaumur
Rankine
Kelvin

But the 7 not the 6 is a fine number! Do you know 7-th temperature scale? I Know!

Re: How can I have Celcius not Kelvin on the X-axes of Prime plot

Fred_Kohlhepp — Wed, 10 Apr 2019 13:16:34 GMT

@Werner_E wrote:

So the bug was freshly introduced with Prime 5 (and we thought there would be no development of Prime any more 😉

And the beat goes on . . . .

I guess with the new fancy graphing utility the built-in graphs could be farmed out to the interns.

Re: How can I have Celcius not Kelvin on the X-axes of Prime plot

LucMeekes — Wed, 10 Apr 2019 15:20:51 GMT

First please explain the difference between 'Celsius' and 'centigrade' .

Luc

Re: How can I have Celcius not Kelvin on the X-axes of Prime plot

Fred_Kohlhepp — Wed, 10 Apr 2019 17:28:48 GMT

I agree:

From WIKIPEDIA:

Before being renamed to honor Anders Celsius in 1948, the unit was called centigrade, from the Latin centum, which means 100, and gradus, which means steps.

Re: How can I have Celcius not Kelvin on the X-axes of Prime plot

ValeryOchkov — Wed, 10 Apr 2019 19:34:32 GMT

@Fred_Kohlhepp wrote:

I agree:

From WIKIPEDIA:

Before being renamed to honor Anders Celsius in 1948, the unit was called centigrade, from the Latin centum, which means 100, and gradus, which means steps.

sorry - not so simple

Re: How can I have Celcius not Kelvin on the X-axes of Prime plot

LucMeekes — Wed, 10 Apr 2019 20:05:51 GMT

So, with that settled (Thanks! Fred),

the 6th through 8th temperature scales, or units, could be Delisle, Newton and Romer;

per https://en.wikipedia.org/wiki/Conversion_of_units_of_temperature#Comparison_of_temperature_scales

Of these, Delisle is interesting because it goes hotter for lower values...

Luc

Re: How can I have Celcius not Kelvin on the X-axes of Prime plot

Werner_E — Wed, 10 Apr 2019 21:07:12 GMT

@ttokoro

Valery needs/wants °C on the abscissa!

Re: How can I have Celcius not Kelvin on the X-axes of Prime plot

Werner_E — Wed, 10 Apr 2019 21:16:56 GMT

@Fred_Kohlhepp wrote:

@Werner_E wrote:

So the bug was freshly introduced with Prime 5 (and we thought there would be no development of Prime any more 😉

And the beat goes on . . . .

I guess with the new fancy graphing utility the built-in graphs could be farmed out to the interns.

At least this new plot add-in can't show the bug in question here as it is totally unit-unaware. Hurray!

Re: How can I have Celcius not Kelvin on the X-axes of Prime plot

ttokoro — Thu, 11 Apr 2019 01:35:58 GMT

I understand what is the problem. X-axes allows K or R and not degree C or degree F. (x=x*unit ,not x=x*unit+C*unit)

So x axes can use the unit of delta degree C.

Re: How can I have Celcius not Kelvin on the X-axes of Prime plot

Fred_Kohlhepp — Thu, 11 Apr 2019 02:23:33 GMT

But Prime 4 (Expresseven) allows deg C on the x axis as well

Re: How can I have Celcius not Kelvin on the X-axes of Prime plot

ValeryOchkov — Thu, 11 Apr 2019 05:15:33 GMT

One interesting Mathcad Web-sheet:

The International Temperature Scale of 1990 (ITS-90)