Table of Contents
Advertisement
MERLIN NX IP AND MST/TP VAV CONTROLLER - INSTALLATION INSTRUCTIONS
POWER SUPPLY
General Information
To prevent a risk of injury due to electrical shock and/or
damage to device due to short-circuiting, low-voltage and
high-voltage lines must be kept physically separate from
one another. Further, to prevent a risk of short-circuiting
and damage to your unit, do not reverse the polarity of the
power connection cables, and avoid ground loops (i.e.,
avoid connecting one field device to several controllers).
Before wiring the controller, determine the input and output
device requirements for each controller used in the system.
Select input and output devices compatible with the
controller and the application. Consider the operating
range, wiring requirements, and the environment conditions
when selecting input/output devices.
Determine the location of controllers, sensors, actuators
and other input/output devices and create wiring diagrams
for illustrations of typical controller wiring for various
configurations.
The application engineer must review the control job
requirements. This includes the sequences of operation for
the controller, and for the system as a whole. Usually, there
are variables that must be passed between the controllers
that are required for optimum system wide operation.
Typical examples are the TOD, Occ/Unocc signal, the
outdoor air temperature, the demand limit control signal,
and the smoke control mode signal.
It is important to understand these interrelationships early in
the job engineering process, to ensure proper
implementation while configuring the controllers.
NOTE:
All wiring must comply with applicable electrical
codes and ordinances. Refer to job or manufacturers'
drawings for details. Local wiring guidelines (for
example, IEC 364-6-61 or VDE 0100) may take pre-
cedence over recommendations provided in these
installation instructions.
To comply with CE requirements, devices having a
voltage of 50-1000 VAC or 75-1500 VDC but lacking
a supply cord, plug, or other means for disconnecting
from the power supply must have the means of dis-
connection incorporated in the fixed wiring. This type
of disconnection must have a contact separation of at
least 1/8 in. (3 mm) at all poles.
EN1Z-1076GE51 R1021
Power Wiring
All wiring must comply with applicable electrical codes and
ordinances, or as specified on installation wiring diagrams.
Controller wiring is terminated to the screw terminal blocks
located on the device.
NOTE:
For multiple controllers operating from a single trans-
former, the same side of the transformer secondary
must be connected to the same power input terminal
in each controller.
All loads on the controller must be powered by the
same transformer that powers the controller itself. A
controller can use separate transformers for control-
ler power and output power.
The 24 VAC power from an energy limited Class II power
source must be provided to the controller. To conform to
Class II restrictions (U.S. only), the transformer must not be
larger than 100 VA.
NOTE:
Power must be off prior to connecting or removing
connections from the 24 VAC power (24 V~/24 V0),
and 20 VDC power (20 VDC) terminals.
Use the heaviest gauge wire available, up to 18 AWG
(1 mm2), with a minimum of 22 AWG (0.3 mm2), for
all power wiring.
CAUTION
CAUTION
Where multiple devices are powered from a single
transformer, the same side of the transformer
secondary must be connected to the same power
input terminal in each device.
14
Advertisement
Table of Contents
