GE Mark VIe System Manual page 38

1.6.1.2 Dual Controllers
The dual control architecture contains two controllers, two IONets, and singular or fanned TMR I/O modules. The following
diagram displays a Mark VIe control system with a Dual redundancy configuration.
Legend
IONet <R>
IONet <S>
UDH
The dual control Mark VIe architecture reliability can be significantly better than the single controller. The network and
controller components are redundant and can be repaired online. The I/O reliability can be mixed and matched to meet
varying requirements.
In a dual Mark VIe control system, both controllers receive inputs from the I/O modules on both networks and transmit
outputs on their respective IONet continuously. When a controller or network component fails, the system continues
operating. I/O packs receive inputs from both controllers, but prefer the designated controller. If the only packet received is
from a non-designated controller, then the I/O pack will use that packet.
Note With dual controllers, the level of I/O reliability can be varied to meet the application needs because not all I/O has to
be dual redundant.
The Mark VIe controllers listen for the data on both networks at power on. The channel that delivers the first valid packet
becomes the preferred network. As long as the data arrives on that channel the controller uses this data. When the preferred
channel does not deliver the data in a frame, the other channel becomes the preferred channel as long as valid data is supplied.
This prevents a given controller from bouncing back and forth between two sources of data. This does mean that different
controllers may have separate preferred sources of data but this can also happen if any component fails.
The I/O modules listen for the data on both networks at power on. If the packet from the designated controller is received, that
one is the preferred network. When the designated controller packet does not arrive in a given frame, the other channel is used
as long as valid data is supplied.
38 GEH-6721_Vol_I_BP
R S
Dual Mark VIe Control System
GEH-6721_Vol_I Mark VIe and Mark VIeS Control Systems Volume I
Public Information
Controllers
Switches
I/O Modules