Irregular D/A conversion is one of the problems involved in
Networked Control Systems. These are a special kind of control
systems, in which the communication between controller and
continuous plant to be controlled is performed through a shared
medium. Due to the irregular distribution of the utilization of
the shared link, the arrival instants of the control actions sent by
the controller are not regularly spaced in time. Typically, the
control actions are applied to the continuous plant holding their
values with a zero order holder. In an event driven D/A
converter, the control signal changes with the arrival of a new
action. If the actions arrive in an irregular pattern, the signal
held by the converter will be also irregular. This irregularity
will cause degradation of the performance and loop instability.
The paper presents a procedure to obtain a model of the discrete
equivalent of the plant dynamic, including the irregular
behavior caused by the shared link. This model can be used to
design a controller deal with irregular D/A conversion, avoiding
its detrimental effects.