What is the correct way to wire an output from an RO-4 configured as "SC" (4-20 mA) to an analog input point on a Johnson Controls XP-9102?  Is external loop power required by the RO-4 output (as in, does the +15vdc loop power have to come from the XP-9102), or is loop power already provided by the RO-4?

David, good questions.  The RO-4' s current outputs, both SC and UC, are sourceing meaning that they do not require external voltage.  If external voltage is applied it will damage the output.