Hardware
Installation
15
The WattNode may be purchased with the following transceivers:
Transceiver
Bit Rate
Max. Nodes
1
Max. Distance
Max. Stub Length
TPT/XF-78
78 Kbps
64
1400 m
3.0 m
FTT-10
78 Kbps
64
500–2700 m
3.0 m
2
1
Per subnet (see Echelon LonWorks Products Databook for more details)
2
Only applies to bus topology networks.
Table 2.1: WattNode Transceivers
The FTT-10 transceiver is compatible with LPT-10 Link Power Twisted Pair networks.
The twisted pair networks are not polarized, so either network wire can be connected to either screw
terminal. When connecting to a network, there is a maximum permissible stub length. The stub is the
length of the branch wire connecting the main network to the WattNode. If the main network wiring is
connected directly to the WattNode, the effective stub length is zero.
To connect the network wiring, strip the wires to expose 1/4" (6 mm) of bare wire on each of the two
conductors. Then connect one conductor to each of the two terminals labeled ‘
Network
’ on the black
terminal block. If the WattNode is connected without a stub, then two wires can be connected to each
terminal. Each terminal should have one wire for each direction on the network. If this is done, then take
extra care with the two wires in each terminal slot, so that they are both securely tightened. Any loose
wires could disable an entire section of the network.
After the network wiring has been connected, check that all the wires are securely installed by gently
tugging on each wire in turn. Also check that the terminal block connectors are completely seated. At this
point power may be applied to the WattNode. Note: there is no harm in applying power before making the
network connections.
2.7 Installation Summary
1)
Mount the WattNode.
2)
Turn off power before installing toroidal CTs or making voltage connections.
3)
Place the current transformers (CTs) around the line wires of the circuit being measured. Take care
to orient the CTs correctly.
4)
Connect the twisted white and black wires from the CT to the black terminal block on the
WattNode, matching the wire colors to the white and black dots on the label of the WattNode.
5)
Jumper any unused CT inputs with an insulated shorting wire.
6)
Connect the voltage wires to the white terminal block of the WattNode, and double check that the
current measurement phases match the voltage measurement phases.
7)
For twisted pair networks, connect the network wires (polarity is unimportant).
8)
Turn on power for the WattNode.
