Ross ACO-4400A, User Manual, Page: 49 / 112

ACO-4400A User Manual (Iss. 03) Operating Basics • 4–5
Operating Basics
The ACO-4400A can be thought of as an automatic multi-pole switch that actuates whenever an
error is detected in any BNC signal channel. All channels will switch at the same time.
Any unused BNC input channel should be configured to disable error checking. If unused
channels are not disabled, they will always produce error signals leading to improper operation.
Error threshold levels are pre-defined during initial testing, and are not adjustable.
Operating Mode
The ACO-4400A can be operated in one of two modes, selected from within the menu system.
The options are either Automatic or Manual control. When “Auto” is selected, the ACO-4400A
will automatically switch if a fault is detected. When “Manual” is selected, the ACO-4400A will
switch only when the operator manually selects between Primary and Backup.
Fault Reporting
There is an LCD indication for fault reporting on all channels. If a fault occurs in one of the
configured channels on either the Primary or Backup input, the LCD indicator will illuminate to
report the fault. The fault reporting is persistent, i.e. even if the fault is only an intermittent one,
the fault indicator will stay illuminated. If more than one fault exists, only the “first” one is
reported, i.e. counting from the lowest numbered configured channel. As faults are repaired, the
fault indicator displays the next faulty input/channel in the list, etc. Repairing the last fault will
update the LCD display to show that the [last] fault has been fixed - clearing the fault indication
will turn the LCD fault indication off.