The interoperability of equipment as sensors, actuators, PLC regulatio
n or DCS is their global capability to exchange information in order t
o meet the end user requirements. The conformance testing of each syst
em to a communication standard is not sufficient to prove interoperabi
lity. Examples are given. After a presentation of the interoperability
problem, different test methods are presented, starting from the conf
ormance testing approach. The interoperability testing solution for co
mponents as sensors (or actuators) implies various constraints which a
re not identical in other areas (interoperability of computers, operat
ing systems with some communication profile). Several types of interop
erability have been introduced and are analysed. A particular kind of
test to verify the capabilities of equipment to be configured in the r
ight way is explained. This test method is applied to test the interop
erability of FIP compatible equipment.