network thermostat NT-485 NetX Modbus Translator Installation Guide
- June 6, 2024
- Network Thermostat
Table of Contents
- network thermostat NT-485 NetX Modbus Translator
- WHAT IS IN THE BOX?
- HARDWIRE INSTALLATION
- CABLE TERMINATIONS
- MODBUS ADDRESS SETTING
- MODBUS COMMS CONFIGURATIONS
- ONE (1) YEAR LIMITED WARRANTY
- SPECIFICATIONS
- Sensors: 1-2, 3-5, 6+ Sensors
- FINAL ASSEMBLY DIAGRAM
- Read User Manual Online (PDF format)
- Download This Manual (PDF format)
network thermostat NT-485 NetX Modbus Translator
BEFORE YOU START
Please read the entire install manual. The NT-485 will need tobe correctly
wired and configured for proper operation.
INTRODUCTION
The Network Thermostat NT-485 Modbus translator is designed to allow Modbus status and control of basic thermostat functions when connected to an X-series thermostat. The NT-485 resides on the wired Remote Sensor Bus (RSBus) along with the other NetX sensor types (such as the NT-URS). The Modbus MS/TP points are listed in the document “240319 NT-485 Modbus Points List”.
WHAT IS IN THE BOX?
- (1) NT-485 Modbus Translator
- (2) 3/16 Drywall anchors
- (2) Mounting Screws
- (1) Installation Manual
NT-485 CALLOUT
- Diagnostic LED
- Number of Sensors Jumper
- Wiring to Thermostat
- 485 Termination
- Wiring to BAS System (Modbus MS/TP)
MOUNTING LOCATIONS
For proper operation, the NT-485 must be mounted in an interior location.
HARDWIRE INSTALLATION
-
Install the X-Series thermostat according to the instruction manual supplied with it.
-
Install NT-485 in a convenient location for wiring access to both the X-Series thermostat and the BAS system.
-
Install RSBus cable (Red Arrow) from the thermostat to the NT-485 location. NT-URS sensors may be placed before or after the NT-485. The maximum distance is 300ft. (90m).
Use CAT5 or CAT5e unshielded, or 1-Pair Twisted Shielded Cable with Drain and nominal capacitance of 12 pF/ft or less, such as Connect Air W221P-2003NT available from Network Thermostat.
Use Riser-Rated or Plenum Rated cable as required by local code. -
Install Modbus cable (Blue Arrow) from the BAS System to the NT-485 location. Maximum distance is 300ft. (90m) While not required, the same cable type may be used.
Typically, a 1-Pair Twisted Shielded Cable with Drain and nominal capacitance of 12 pF/ft or less or advantageous for RS-485 networks.
Use Riser-Rated or Plenum Rated cable as required by local code
CAUTION: Disconnect power to the thermostat or remove thermostat faceplate before connecting either end of the cable.
CABLE TERMINATIONS
THERMOSTAT TO NT-485
-
After mounting the thermostat and NT-485, run the sensor cable from the thermostat to the NT-485.
-
Strip 1/4 inch of insulation from three wires at the NT-485. Install the wires in the terminals using the table below.
Cat5/Cat5e cable color code:
RS+V = Green with White Stripe
RS2 = Brown with White Stripe
RS1 = Green
or
1-Pair Shielded cable color code: (W221P-2003NT)
RS+V = White
RS2 = Drain wire
RS1 = Black
NOTE:
Be careful with the wire color going to each terminal. The order of the terminals on the thermostat are not the same as the NT-485. -
Strip 1/4 inch of insulation from the same three wires and connect to the thermostat backplate terminals labeled RS1,RS2 and RS+V.
NT-485 TO MODBUS MS/TP
Run the Modbus cable from the NT-485 to the Modbus MS/TP device.
-
Strip 1/4 inch of insulation from the 1-pair conductors at each end of the cable. Install the wires in the terminals using the table below.
1-Pair Shielded cable color code: (W221P-2003NT)
A (+) = White
B ( – ) = Black
GND (no label on terminal) = Drain wire (optional) -
Connect the wires to the appropriate terminals on both ends for Modbus MS/TP communications.
RSBUS LOADING – JUMPER SETTINGS
The RSBus allows multiple devices/sensors to be connected on the bus. The
NT-485 counts as one of those devices.
Therefore, the #Sensors jumper must be set appropriately for reliable
communications between the thermostat and the remote devices/sensors.
Set the jumper to match the total number of sensors directly connected to the thermostat; 1-2, 3-5, or 6+ sensors.
IMPORTANT: Do Not Count The Additional NT-URS Sensors Used For Indoor Averaging.
Sensor Counting Example 1:
You are connecting an NT-485, an NT-URS (INDOOR) sensor, an NT-URS (OUTDOOR)
sensor, and an NT-URS (AUX1) sensor. The sensor count is 4 and the correct
jumper configuration is the middle jumper 3-5.
SENSOR TYPE CONFIGURATION
Sensor Counting Example 2:
You are connecting an NT-485 and six (6) NT-URS (INDOOR) sensors (Averaged).
The sensor count is 2 and the correct jumper configuration is the top jumper
1-2.
Sensor Counting Example 3:
You are connecting an NT-485, an NT-URS (INDOOR) sensor, an NT-URS (OUTDOOR)
sensor, an NT-URS (AUX1),an NT-URS (AUX2) sensor, an NT-URS (Water Leak)
sensor. The sensor count it 6 and the correct jumper configuration is the
bottom jumper 6+.
X-SERIES THERMOSTAT SETUP FOR MODBUS
The X-Series thermostat has a dot matrix display at the top of the touchscreen. The touchscreen can be used for determining of the NT-485 is connected to the thermostat, and for setting the NT-485 Modbus address.
-
Reattach the X-Series thermostat faceplate after cable connections are completed and verified. (See your thermostat installation manual for instructions.)
-
After power-up, it will take up to 1 minute for the X-Series thermostat to initially find and communicate with the NT-485 on the RSBus.
When communications has been established, the dot matrix will display:
Modbus Active for 5 seconds and then return to normal functionality. -
Each time the thermostat communicates with the NT-485, the GREEN LED will blink. This indicates normal connection between the thermostat and the NT-485.
MODBUS ADDRESS SETTING
- To set the Modbus address from the touchscreen, press the Menu button in the lower-left corner of the screen and hold for 5 seconds and then release.
The thermostat will now be in the Installer Menu.
Navigate to the Modbus Address menu section, and use the + and – buttons to set the address, then tap the to save.
NOTE: The Modbus address may also be set over Modbus communications
MODBUS COMMS CONFIGURATIONS
BAUD RATE: 9600
DATA BITS: 8
PARITY: EVEN
STOP BITS: 1
LED STATUS
The NT-485 includes a Diagnostic LED that can help you troubleshoot your
installation and sensor operation.
LED Off:
LED OFF indicates no power to the NT-485. Check wiring between the NT-485 and
the thermostat for problems. Fix as necessary.
LED On Solid During Power-Up:
On power-up, the LED will turn on solid until the NT-485 successfully
communicates with the thermostat.
LED Blink:
The LED will blink during communications with the thermostat; approximately
every 15 seconds.
ONE (1) YEAR LIMITED WARRANTY
Network Thermostat™ warrants to the original purchaser that this product will
be free from defects in workmanship and materials for a period of one year
from the date of purchase with proof of purchase.
Warranty Limitations
This warranty begins on the date of purchase.
Warranty is Void if:
- The date code or serial number is defaced or removed.
- The product has a defect or damage due to product alteration, connection to an improper electrical supply, shipping and handling, accident, fire, flood, lightning or other conditions beyond the control of the manufacturer.
- The product is not installed according to the manufacturer’s instructions and specifications.
Owner’s Responsibility
- Provide proof of purchase.
- Provide normal care and maintenance.
- Pay for freight, labor and travel.
- Return any defective product.
- In no event shall the manufacturer be liable for incidental or consequential damages.
This warranty gives you specific legal rights and you may have others which vary by state and/or province. For example, some states and/or provinces do not allow the exclusion or limitation of incidental or consequential damages, so this exclusion may not apply to you. The manufacturer’s continuing commitment to quality products may require a change in specifications without notice.
SPECIFICATIONS
Rated Voltage:
20V to 30VAC, 24VAC nominal
Modbus Communications Settings:
Baud: 9600
Data Bits: 8
Parity: Even
Stop Bits: 1
Terminations:
RSBus: RS1 – Data, RS+V – Power, RS2 – Return
Modbus: A, B, GND (optional)
Sensors: 1-2, 3-5, 6+ Sensors
Dimensions:
3.6”H x 2.0”W x 1.2”D (90.4mm x 51mm x 30mm)
Approved Cable Types:
CAT5 or CAT5e unshielded, or 1-Pair Twisted Shielded Cable with Drain and
nominal capacitance of 12pF/ft or less. Use riser or plenum jacket as required
by local code.
Maximum 300ft Total Sensor Cable Length per Thermostat
MODBUS POINTS LIST
See Network Thermostat Document 240319
FINAL ASSEMBLY DIAGRAM