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NOTE:
Multiple controllers may be powered from a single transformer. Recommend 5VA for
transformer sizing when designing power configurations. It is recommended that zones
or specific areas are powered in groups, and that not all controllers within the system
are powered from a single transformer.
COMMUNICATIONS BUS WIRING
The BASYX VAV / VVR can be used in a stand alone configuration with a wall mounted sensor, with a PSC in smaller
applications, or in an array utilizing hundreds of units. When used in an application smaller than 32 total units, a
minimum of one (1) PSC must be installed. If used in a large array they must be used in conjunction with the BASYX
SCM Supervisor System and the required number of BASYX UBE Communications Expanders. Up to 32 BASYX
UBE expander boards can be connected to the BASYX Supervisor. In turn up to 32 BASYX VAV / VVR or other
system controllers can be connected to each communication expander providing great flexibility to conform to any
building’s physical installation requirements.
All communication wiring consists of a shielded, plenum rated cable (See Figures 9 & 10). Use 22 AWG, twisted pair,
stranded, shielded, plenum rated cable (Recommended Belden 6500FE) for all communications wiring. In lieu of the
6500FE cable, a stranded 2 pair cable with individually paired shields may be used. When connecting a channel of
controllers, connect communications in a daisy chain configuration.
Communication is via EIA RS-485 protocol. This requires that the system be wired according to the following
methods and rules:
•
Communications cable must be 1 twisted pair (Belden 6500FE), 22 AWG, plenum rated.
•
The total distance from the UBE expander to the last VAV / VVR in the daisy chain must
not exceed 4000 feet.
•
The drain wire of the communication cable must
NOT
be connected to the
VAV / VVR controller, twist shield wires together to create single shield for the entire daisy chain
and connect to ground at one end only (suggest at the UBE location).
•
Connection of the REF terminal on the VAV / VVR controller is
NOT
required.
•
Each VAV / VVR in the daisy chain must have a unique address. Refer to the
instructions below for setting the Device Address (ADDR) dip switch.
Connect the communications wiring to the terminal blocks on the edge of the VAV / VVR assembly , -,
and REF as shown in Figure 9.
CAUTION:
All communication wiring must be connected such that the plus (+)
terminal is wired to a plus terminal and the minus terminal (-) is
wired to a minus terminal. Do not install communications cables near
power cables or in power conduits. Isolate all communications wiring
from large motors, fluorescent lighting fixtures or other sources of
high intensity electromagnetic interference (EMI).
