BAC-7302 RTU Controller
Revision E
Operating the controller
Controls and Indicators
17
Nomad patterns
There are three Com LED patterns that indicate that the controller
is an automatic addressing nomad controller that is receiving valid MS/TP traffic.
Error conditions for the LEDs
The two network isolation bulbs (KMC P/N HPO-0054), located next to the network
switch, serve three functions:
◆
Removing the bulbs opens the EIA-485 circuit and isolates the controller from
the network.
◆
If one or both bulbs are lit, it indicates the network is improperly phased. This
means that the ground potential of the controller is not the same as other
controllers on the network.
◆
If the voltage or current on the network exceeds safe levels, the bulbs operate as
fuses and may protect the controller from damage.
Isolation bulbs
The two network isolation bulbs (KMC P/N HPO-0054), located next to the network
switch, serve three functions:
◆
Removing the bulbs opens the EIA-485 circuit and isolates the controller from
the network.
◆
If one or both bulbs are lit, it indicates the network is improperly phased. This
means that the ground potential of the controller is not the same as other
controllers on the network.
◆
If the voltage or current on the network exceeds safe levels, the bulbs operate as
fuses and may protect the controller from damage.
Table 3-2 Automatic addressing nomad patterns
Controller state
LED pattern
Lost nomad
A long flash
Wandering nomad
A long flash followed by three short
flashes
Assigned nomad
Three short flashes followed by a long
pause.
