Image Processing Reference
In-Depth Information
Inter-
operability
level
Inter-
connectable
Inter-
workable
Inter-
operable
Inter-
changeable
Incompatible
Compatible
Necessary
agreements
Temporal
behavior
Functional
behavior
Data
semantics
Definition of
the data
Access to the
data
Protocol
(layers 1-7)
FIGURE .
Application functionalities within the interoperability definitions.
standards, to be precise) define the rules that the system components must comply with to be able
to work with other components, but they often leave room for interpretation, and actual implemen-
tations may vary. Certification of the devices is a suitable way to reduce the problems, but by no
means a guarantee. Another reason for troubles is that the semantics of data objects are not precisely
defined. In fact, there are various degrees of interoperability, as defined by the IEC TC SCC WG
within the scope of the IEC “Interoperability Definitions” (Figure .). .).These definitions relate to
application functionalities that can be achieved, i.e., the degree to which devices and applications can
actually work together.
Incompatible.
The two communication partners have no common ground and their connection, if
physically possible, could result in damage. he connectors, voltage levels, and modulation methods
canbediferent.
Compatible.
The most fundamental requirement is that both devices use the same communication
protocol. hey can be connected and may exchange data packets. Still, compliance with the protocol
(as verified, e.g., by conformity tests according to ISO ) alone does not guarantee meaningful
cooperation between the applications as they cannot make sense of the received packets.
Interconnectable.
he partners have the same methods of accessing the data, and they mutually under-
stand the addressing methods used by the partner. his is important because the exact way in which
dataaremadeavailableinthenetworkisnotdeinedbytheprotocollayers;theyjustoferanumberof
services for data transmission. Being interconnectable, the partners can recognize whether received
messages were addressed to them, and they are capable of extracting the data (or encoding them in
the opposite direction). Furthermore, they use the application layer services in the same way and
have a common understanding of data types use for their applications.
Interworkable.
Applications share the same definitions of data, and they use the same variable types.
Therefore, they can correctly exchange data using a common way of coding. As an example, a sensor
can send its value in long_int format, and a controller can correctly receive and process this value.
Usually, the development tools offer support for this level. If the tools are designed for distributed
systems, errors violating interworkability can already be detected in an early development phase.
