cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
Showing results for 
Search instead for 
Did you mean: 

Celsius grade error

ptc-6026671
1-Newbie

Celsius grade error

Mathcad Prime Express 3.0:

img000017.png

This is ingenious!!!

Michal Glebowski

5 REPLIES 5

Looks like a conversion to Kelvin is done prior to the calculation. Or a conversion to some other absolute unit of measure for temperature. All in all, though, kind of disturbing.

Even if it is converted to Kelvins (it can be as there is no similar problem with Kelvins) I would expect rather value 2 with some noise, not 1... This conversion must be very rough.

Why would you expect 2?

275 / 274 = 1.0036...

It might be helpful to know why you're calculating the ratio of two temperatures. Is the ratio being looked for actually the ratio of two temperature changes, i.e. (T2 - T1) / (T4 - T3)? If so, you might have to explicitly make the relation ignore units in order to obtain the expected results.

Ok, now i see how it's calculated. And why such result appears. As a matter of fact there are some expressions which require dividing temperatures themselves.

I have empirical equation (Yaws) for heat capacity which includes temperature in some powers (Cp=A + BT + CT^2 + DT^3). To obtain value (to be able to process calculation with no units error) I have to divide each T by 1°C. Of course problem is a little more complicated as original expression is in Kelvines so to get each T i have to add 273.15.

Better

00.png

Announcements
Check out the latest
Mathcad Tip
"PTC Mathcad 15 / Prime 1-6 Update."