Input and Output Terminals
The input spade terminals are located on the bottom of
the VMA near the N2/FC Bus terminal block. The output
spade terminals are located on the top of the controller
near the power supply spade terminals. See
Table 4
for
more information.
N2/FC Bus Terminal Block
The N2/FC Bus terminal block is a blue, removable,
4-terminal plug that fits into a board-mounted jack.
Wire the removable N2/FC Bus terminal block plugs on
the VMA and other field controllers in a daisy-chain
configuration using 3-wire twisted, shielded cable as
shown in
Figure 4
. See
Table 5
and
Table 6
for more
information.
Figure 4: N2/FC Bus Terminal Block Wiring
Note:
The Shield terminal (SHLD) on the N2/FC Bus
terminal block is isolated and can be used to
connect the cable shields on the bus (
Figure 4
).
SA Bus Spade Lugs
Wire the SA Bus spade lugs on the VMA and other SA
Bus devices in a daisy-chain configuration using 4-wire
twisted, shielded cable as shown in
Figure 5
. See
Table
6
for more information.
Figure 5: SA Bus Spade Lug Wiring
Note:
Connecting an IOM to the VMA by using the SA
Bus connection is not supported.
Modular Port
The modular (TSTAT) port on the face of the VMA
(
Figure 3
) is an RJ-45, 8-position modular jack used to
connect your new or existing sensor to the VMA using
one of the two included adapters. Refer to the Sensor
Replacement section in the
N2 VMA Application Note
(LIT-12011829)
.
Figure 6: Pin Number Assignments for the Modular
Port on VMA18 Controllers
6
VMA1826/1832 VAV Controller Installation Instructions
