Compound IF statement with text

I have seen compound IF statements that evaluate numerical values.  e.g.  if (a=1,2,3)

How can I construct a compound IF statement where the variable being evaluated is text?  I want the IF loop to run if the text value Fault is A or B.

e.g.  if (Fault="A", "B")

thanks,

relayman

p.s. Prime 8