Table 10: SNC LED designations, normal statuses, descriptions, and other conditions
LED name
Color
State
Description
Flashing blue
and purple
1 blink per second (1 Hz) = Normal operating system and all monitored
processes start and the device is running
On blue
Power is supplied by 24 VAC, but controller is non-operational
Medium flicker,
purple and blue 2 blinks per second (2 Hz) = SNC starting up
Fast flicker,
purple and blue 5 blinks per second (5 Hz) = SNC shutting down
HEARTBEAT
Multi-color: blue
or purple
Off
No power
Off
No faults and normal operation
FAULT
Red
On
Device fault or no application loaded. Diagnostics are running or fault
conditions are detected. For example, excessive memory or flash usage, or a
high CPU/PWB temperature.
Flashing
1 blink per second (1 Hz) = indicates communication activity
SA BUS
Green
On
Devices have been defined but none are communicating (network engine
transmitting only)
Flashing
1 blink per second (1 Hz) = indicates communication activity
Off
No devices are communicating or no controllers have been configured to
work with this bus
FC BUS
Green
On
Controllers have been defined but none are communicating (network
engine transmitting only)
Flickering
Data is transferring on the Ethernet connection
ETH-1 and ETH-2
Green
Off
No communications
Flashing
Flash green = 1 blink per second (1 Hz), an approved device or devices are
connected and communicating correctly to either USB-1|2
On
Solid red = an unapproved device is connected to USB 1 and/or USB 2. In this
case a user needs to sequentially remove each device until the LED flashes
green or the LED is turned off.
Note:
Only approved USB adapters that have been tested and
qualified function with the SNC. Non-qualified adapters do not
function with the SNC.
USB-1|2
Green or Red
Off
No USB device is connected
On
On Steady = end-of-line termination is enabled for the Field Bus connection
EOL
Yellow
Off
Off Steady = indicates the end of line termination network is disabled
F4-SNC Installation Guide
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