C. Propagation Time
The propagation time, prop T , depends on the signal
transmission speed and the distance between the source and
destination nodes. For the worst case, the propagation delays
from one end to the other of the network cable for these three
control networks are: T s prop = 25.6μ for Ethernet (2500 m),
T s prop = 10μ for ControlNet (1000 m), and T s prop = 1μ for
DeviceNet (100 m). The length in parentheses represents the
typical maximum cable length used. The propagation delay is
not easily characterized because the distance between the
source and destination nodes is not constant among different
transmissions. Note that prop T in DeviceNet is generally less
than one bit time because DeviceNet is a bit-synchronized
network. Hence, the maximum cable length is used to
guarantee the bit synchronization among nodes.
III. MODEL OF NCSS UNDER NETWORK INDUCED DELAY
Networked Control Systems (NCSs) is a type of closedloop
control system with real-time communication networks
imported into the control channel and feedback channel. The
typical NCS model consists of a continuous linear timeinvariable
plant and a discrete controller.