[D.ko]

In user fortran

I coded using USER_GETVAR functionlike below

call USER_GETVAR ('H2Og.T', CRESLT,
& Tc, CZ, DZ, IZ, LZ, RZ)
IF (CRESLT .NE. 'GOOD') GO TO 999

tcoef=1-(TC/647.096)

Tc has range from 250K to 400K
so tcoef should be a positive value.

But when I return the value tcoef and using it as a source term it shows a negative value when I see the source value through cfx solver plot graph.

My goal is to get tcoef**1.256 but tcoef has a negative value so I cannot calculate tcoef**1.256. How can I get proper value?
'tcoef' must be a positive value. it cannot be negative.