The Constrain tab lets you define a parameter to be a constant value, but one value for all data sets. What if you want a different constant value for each data set?  Prism offers two ways to do this:

•Use the column title as the constant value.

•Use special notation within a user-defined equation to assign a different value for each data set. For example:

<A>Bottom=4.5

<B>Bottom=34.5

<C>Bottom=45.6

Y=Bottom + span*(1-exp(-1*K*X))

In this example, the parameter Bottom is set to 4.5 when fitting data set A, to 34.5 when fitting data set B, and to 45.6 when fitting data set C.