ETC CEM3 v1.5.1 - Manual (Page 58)

52 CEM3 User Manual
Automatic Control
Typically, in a redundant tracking system, the switch should be left in the auto position.
When the switch is set to auto, the A processor will have control by default. Control will
switch to B when any of the following events occur.
Loss of network
If network connectivity is lost to one processor but not the other, control will switch to the
one which still has network connectivity.
Loss of DMX
If DMX is lost by one processor but not the other, control will switch to the one still able to
receive DMX (note that the DMX data line is interconnected between both, so this would
only occur in the event of the failure of a DMX transceiver on the processor itself).
Power errors
If one processor experiences power errors but the other does not, control will switch to the
one that does not. Again, note that the same power is connected to both processors so this
would only occur in the event of an internal failure in the processor.
Total processor loss
If communication is completely lost to one processor but not the other, then control will
switch to the processor which is still available.
Display Status
When tracking is active and the A processor is in control, the displays will show as follows:
When control switches to the B processor (either by automatic failover or manual control
using the switch), the displays change to the following:
Rack 1 - CEM3 Rack
System OK
DMXA: 1 DMXB: Off
sACN: 2/1
[Info]
CEM3 Control
Backup Ready
Processor A
Processor B