Table 4: Network Engine LEDs designation, normal status, description, and other conditions
LED
Normal
Descriptions/Other Conditions
Run (Green)
On Steady
On Steady = network engine software is running.
On 1 second, Off 1 second = network engine software is in startup
mode.
On 0.5 seconds, Off 0.5 seconds = network engine software is
shutting down.
Off Steady = Operating system is shutting down or software is not
running.
24 VAC (Green)
On Steady
On Steady = 24 VAC power is present.
Off Steady = Loss of 24 VAC power. In the Off Steady condition,
the network engine can be running on battery power. Also see the
POWER LED.
BATT FAULT (Red)
Off Steady
On Steady = Battery fault. Replace the battery. Battery is not
connected or cannot be charged. The BATT FAULT LED may remain
On for up to 24 hours after initially powering on the network engine.
If the BATT FAULT LED remains on longer than 48 hours after initially
powering on the network engine, check the battery connection or
replace the battery.
GENL FAULT (Red)
Off Steady
On Steady = General Fault. Fault conditions are user configurable in
software. Preconfigured fault conditions include excessive memory
use, excessive flash use, excessive CPU or PWB temperature, and
Battery Fault. In normal operation, the GENL FAULT LED stays on
steady for the first half of the startup sequence.
Wiring considerations and guidelines for network integrations
Table 5: Network Engine Ethernet network rules
Category
Rules and Maximums
General
Star topology with network switches
Number of Devices
Maximum of 1,000 devices permitted at one site in the
Metasys
network.
2,000 m (6,600 ft) for plastic/glass fiber optic with external adapter
Line Length and Type
10 BaseT: 100 m (330 ft) Cat5 or Cat6 cable
100 BaseT: 100 m (330 ft) Cat5 or Cat6 cable
1000 BaseT: 100 m (330 ft) Cat5E or Cat6 cable
Terminations
For 10/100/1000 BaseT, no line terminators allowed.
Table 6: Guidelines for BACnet protocol MS/TP network topology
Category
Rules and Maximums
General
Two MS/TP Bus trunks, daisy chain topology only. No T or star topology
configurations.
NAE55/NIE55 Installation Guide
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