I can't evaluate decimal value to decimal FieldRef

I have a problem with evaluating decimal value into a decimal fieldRef. Everything works ok , but when i try to evaluate values smaller then 0.0001 in tables it shows like '0' and i can't understand why. For example
if i evalueate digit 0.00001 to decimal field via fieldRef it shows zerro.



this is my code:

EVALUATE(TempDecimal,TempText);
TargetField.VALUE := TempDecimal; // insert Decimal value

The variant with TargetField.VALIDATE() do not sute for me !

Regards.