US Utah-400, Setup And Operation, Page: 122 / 157

Troubleshooting
5-8
Troubleshooting
System Controller Alarms
System controller alarms are indicated by LEDs on the front of each controller card.
•
The active LED should be lit on one of the controller cards. If only one controller is present
(non redundant system), the active LED should be illuminated.
Please note the following additional points regarding the controller:
•
The heartbeat LED (DS6) indicates that the processor is communicating with the vital parts
of the system and is running the application software.
•
The MX LEDs indicates communication with the crosspoint matrix. The transmit LED (DS8)
will flash whenever communication is being made from the controller to the matrix. The
receive LED (DS7) will flash whenever communication is being received by the controller
from the matrix.
•
U-Net is used for communication between the controller and the control panels. The U-Net
data and U-Net transmit enable LEDs (DS9 and DS10) indicate when information is
exchanged between the system controller and a control panel.
•
If the active LED is on and the U-Net transmit enable LED (DS10) is off, this indicates that a
controller software upgrade has failed and the controller is waiting for a valid controller soft-
ware upgrade to be uploaded.
•
If used with an SC-4 or SC-400 system controller consult the appropriate controller manual
for details about the controller card.
•
The total MX bus cable length must be less than 300 feet and must be terminated at the last
chassis.