MegaControls NT10 Series Manual

RS-485 Modbus RTU Networking Room Thermostats for Fan Coil Units
Features
■
Ultra slim wall-mount unit to match
any decor
■
Supports standalone operation on RS
-485 communication failure. A power
reset must be carried out on
thermostat before this can take place.
■
Fan coil application database pre-
loaded
■
Large easy-to-read Liquid Crystal
Display (LCD), with LED backlight
■
A stylish bi-directional rotating dial
and two compact touch keys to
provide ease of operation
■
Choice of constant display of ambient
temperature or temperature set point
value
■
Output relays employed for direct
connection of valve actuators and 3-
speed fan
■
Configurable operating parameters
■
Choice of ºC or ºF temperature
display via parameter setup menu
■
2-wire on-off, 3-wire floating and 0-10
VDC output models available
■
Adjustable proportional band for 3-
wire floating and modulating models
■
Adjustable integral time for
modulating models
■
Choice of valve stroke time for 3-wire
floating output models
■
Field adjustable high and low
occupied set point limit settings
■
Field adjustable cooling and heating
unoccupied set point values
(applicable to some models only)
■
Choice to retain last entered settings
on power resumption
■
Dual-output on-off and 0-10 VDC
models with auto cooling/heating
changeover (deadband operation)
and manual override
■
Choice of operating sequence for dual
-output models
■
Adjustable 1 to 5 K deadband for dual
-output models
■
Unoccupied mode capability with field
adjustable cooling and heating set
points, , not available to "1M", 1AM"
and "1FM" models.
■
Choice of unoccupied mode activation
in operating mode only or in both
standby and operating modes
■
Window contact closure to shut down the
FCU and lock out all thermostat functions
■
Provides one additional digital input
Copyright © Mega Controls Limited
NT10 Series
for function such as remote night
setback, service/filter alarm or motion
detection
■
Choice of fan action in unoccupied
mode
■
Choice of auto fan action in heating
mode
■
Field recalibration capability of
measured temperature
■
Continuous or auto fan operation
■
External and seasonal changeover
temperature sensor capability
■
Optional infra-red remote control unit
■
Optional special faceplate color
available on request
General
The NT10 Series RS-485 networking
room thermostats use the communication
technologies of Modbus RTU
communication protocol to monitor and
supervise fan coil units in the heating,
ventilating and air-conditioning industry,
and employ a simple master/slave
protocol. All NT10 Series thermostats are
slaves in this protocol, and can be under
the control of a Mega Controls BACnet
gateway, either BMG or BMGE Series,
called the master. The BMGs and
BMGEs are native BACnet MS/TP
devices and communicate using the
BACnet MS/TP or BACnet-over-Ethernet
protocol. The master can also be a
Modbus network supervisor.
The master and all slaves are daisy-
chained through a RS-485 Modbus RTU
network. The maximum number of NT10
slaves in a Modbus RTU network is 32.
Each BMG has 2 addresses. Net 2
address is always 0 which is the address
of the Modbus RTU network. Net 1
address is the MAC address of the
BACnet MS/TP network which is also set
up for a maximum of 32 devices in a
trunk cable length not exceeding 1000 m.
The BMG gateway spontaneously
detects the presence of slaves that go
online in its NET 2 network.
If more than 32 BMGs are needed in the
system, an additional BACnet system
device is required for the second BACnet
MS/TP network.
Each BMGE gateway is available with
two RS-485 networks. Each network can
Issue Date March 1, 2018
support up to 32 NT10 Series
Modbus RTU devices. The BMGE
gateway spontaneously detects the
presence of slaves that go online
in its NET 1 and NET 2 networks.
The NT10 Series thermostats
cover a wide range of fan coil
applications, including 2 and 4-pipe
fan coils and direct connection to 3
-speed fans. Temperature sensing
can be from a built-in room sensor
or a remote sensor.
A fan-speed control touch key
allows control of a 3-speed fan.
The speed control key has 4
positions: "Hi-Med-Low-Auto". In
the "Hi", "Med" or "low" position,
the fan runs continuously at the
selected speed. In the "Auto"
mode, the fan speed is
temperature dependent and
controlled automatically at 2 K
differential increments from low to
high speed.
Ordering
To order, specify complete model
numbers.
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