Modular Ports
The modular and FC Bus ports on the face of the VMA
(
) are RJ-12 (6-position) modular jacks as shown
in
The modular SA Bus port provides a connection for the
VAV Balancing Tool and NS Series sensors.
Figure 5: Pin Number Assignments for Sensor (SA
Bus and FC Bus) Ports on VMA1615/1630 Controllers
Note:
Do not use the modular SA Bus port and the
terminal block SA Bus simultaneously. Only use
one of these connections at a time.
Supply Power Terminal Block
The 24 VAC supply power terminal block is a gray,
removable, 2-terminal plug that fits into a board-mounted
jack on the upper left of the VMA controller.
Wire the 24 VAC supply power wires from the transformer
to the HOT and COM terminals on the terminal plug as
shown in
. See
for more information.
Figure 6: 24 VAC Supply Power Terminal Block Wiring
Important:
Connect 24 VAC supply power to the VMA
and all other network devices so that
transformer phasing is uniform across the
network devices. Powering network devices
with uniform 24 VAC supply power phasing
reduces noise, interference, and ground
loop problems. The VMA does not require
an earth ground connection. However, when
grounding the secondary of the 24 VAC
transformer is required, only one connection
to ground should be made near the
transformer. See the following figure.
Figure 7: Transformer Grounding
Risk of Property Damage:
Do not apply power to the
system before checking all wiring connections. Improper
wiring of this terminal may cause a short circuit across
the 24 VAC power supply on VMA models. A short circuit
may result in a tripped circuit breaker or blown fuse. If
using a transformer with a built-in fuse, the transformer
may need to be replaced.
Risque de dommages matériels
: Ne mettez pas
l’appareil sous tension avant d’avoir vérifié toutes les
connexions du câblage. Le câblage inadéquat de cette
borne peut causer un court-circuit sur l’alimentation
électrique de 24 V c.a. des -1 VMA modèles. Un
court-circuit peut causer le déclenchement du disjoncteur
ou le grillage d’un fusible. Si vous utilisez un
transformateur avec un fusible intégré, vous pourriez
devoir remplacer le transformateur.
To wire the VMA1615/1630 controller:
1. Terminate wiring according the appropriate figure in
.
2. Wire network sensors and other devices to the VMA's
SA Bus.
3. Wire the FC Bus in a daisy chain.
4. Ensure that the VMA’s device address DIP switches
are set to the appropriate device address. (See
7
VMA1615 and VMA1630 Variable Air Volume Controllers Installation Instructions