Emerson ControlWave Instruction Manual page 62

ControlWave I/O Expansion Rack Instruction Manual
Wiring the Module Figure 3-11 shows field wiring assignments associated with a locally
3-14
operating in online mode monitors the DO values of its standby
counterpart in order to verify that standby DO values are consistent
should a failover occur. Depending upon software configuration
settings; a failover can be prevented if they are inconsistent. A
standard DO module used in a redundant system does not perform this
monitoring; therefore the potential exists to failover to a backup DO
module with failed hardware. For critical processes, the redundant DO
with read-back capability is recommended.
Use the same DO module type in any redundant pair; do not install a
DO with read-back module in the primary rack and a standard DO
module as its redundant counterpart in the backup rack, or vice versa.
See Software Configuration later in this section for details on setting
up DO with readback.
terminated DO module; Figure 3-12 shows a wiring diagram for the
DO. Field wiring assignments associated with remotely terminated DO
modules. Figure 3-13 shows field wiring assignments for a remotely
terminated DO module. Figure 3-14 shows a special remote
termination module with built-in discrete relay modules.
Figure 3-11. Local Terminal Block Assembly Assignments
Source Isolated DO Operation
I/O Modules
for Open
Revised Aug-2015