Carrier RTU Open v3 Quick setup guide

R
RT TU U O Op pe en n v v3 3
I
In nt te eg gr ra at ti io on n G Gu ui id de e
CARRIER CORPORATION ©2016
A member of the United Technologies Corporation family · Stock symbol UTX · Catalog No. 11-808-521-01 · 2/22/2016

Verify that you have the most current version of this document from
www.hvacpartners.com
or your local Carrier
office.
Important changes are listed in
Document revision history
at the end of this document.
CARRIER CORPORATION ©2016. All rights reserved throughout the world. i-Vu is a registered trademark of Carrier
Corporation. BACnet is a registered trademark of ASHRAE. All other trademarks are the property of their respective
owners.

Contents
Introduction.................................................................................................................................................................. 1
What is the RTU Open controller? ......................................................................................................................1
Safety considerations & handling warning.......................................................................................................3
Wiring inputs and outputs........................................................................................................................................... 4
Communications wiring .............................................................................................................................................. 6
Protocol overview..................................................................................................................................................6
BACnet MS/TP ......................................................................................................................................................7
To set up the RTU Open for BACnet MS/TP......................................................................................... 7
Troubleshooting BACnet MS/TP........................................................................................................... 8
Modbus...................................................................................................................................................................9
To set up the RTU Open for Modbus .................................................................................................... 9
Troubleshooting Modbus ....................................................................................................................11
Johnson N2 ......................................................................................................................................................... 12
To set up the RTU Open for N2...........................................................................................................12
Troubleshooting N2.............................................................................................................................13
LonWorks ............................................................................................................................................................ 14
To set up the RTU Open for the LonWorks Option Card (Part #LON-OC) .........................................14
Commissioning the controller for LonWorks communication...........................................................15
Troubleshooting LonWorks .................................................................................................................16
Start-up.......................................................................................................................................................................17
Sequence of Operation .............................................................................................................................................18
Occupancy........................................................................................................................................................... 18
Supply fan ........................................................................................................................................................... 19
Cooling................................................................................................................................................................. 19
Economizer ......................................................................................................................................................... 20
Power Exhaust.................................................................................................................................................... 21
Pre-Occupancy Purge........................................................................................................................................ 21
Unoccupied Free Cooling .................................................................................................................................. 21
Optimal Start ...................................................................................................................................................... 22
Enthalpy control ................................................................................................................................................. 23
Indoor Air CO2 .................................................................................................................................................... 23
Heating ................................................................................................................................................................ 24
Heat Pump operation........................................................................................................................................ 24
Dehumidification ............................................................................................................................................... 25
Demand Limiting ............................................................................................................................................... 25
Door switch ......................................................................................................................................................... 25
Remote Occupancy ........................................................................................................................................... 26
Fire Shutdown .................................................................................................................................................... 26
Compressor Safety ............................................................................................................................................ 26
Fan Status........................................................................................................................................................... 26
Filter status......................................................................................................................................................... 27
Alarms ................................................................................................................................................................. 27
Linkage................................................................................................................................................................ 29
Air source mode determination....................................................................................................................... 31
Troubleshooting .........................................................................................................................................................32
LED's .................................................................................................................................................................... 32
Compliance ................................................................................................................................................................34
FCC Compliance................................................................................................................................................. 34
CE Compliance ................................................................................................................................................... 34
BACnet Compliance........................................................................................................................................... 34

Contents
Appendix A: Network Points List for RTU Open......................................................................................................35
Network points list for BACnet and Modbus ................................................................................................. 35
Network points list for N2 and LonWorks...................................................................................................... 43
Appendix B: BACnet Protocol Implementation Conformance Statement ...........................................................46
Appendix C: Modbus Protocol Implementation Conformance Statement...........................................................47
Appendix D: Johnson N2 Protocol Implementation Conformance Statement....................................................49
Appendix E: LonWorks Protocol Implementation Conformance Statement .......................................................51
Document revision history ........................................................................................................................................52
Index ...........................................................................................................................................................................53

RTU Open v3 Carrier Proprietary and Confidential CARRIER CORPORATION ©2016
Integration Guide All rights reserved
1
What is the RTU Open controller?
The RTU Open controller (part# OPN-RTUM2) is available as an integrated component of a Carrier rooftop unit, or
as a field-installed retrofit product.
NOTE
The RTU Open controller is available in both English or Metric units. The metric version has (-M) appended
to the part number. Everything in this document applies to both versions.
Its internal application programming provides optimum rooftop performance and energy efficiency. RTU Open
enables the unit to run in 100% stand-alone control mode or it can communicate to the Building Automation
System (BAS).
The RTU Open supports the following:
•
ZS Sensors
- 3 models are available for monitoring space temperature, space relative humidity, and space
IAQ/CO2. Sensors provide:
○Space setpoint offset adjustment
○Pushbutton override
○Occupancy indicator
•
Third party protocols
- On-board DIP switches allow you to select the baud rate and choose one of the
following protocols:
○BACnet
○Modbus
○Johnson N2
○LonWorks
•
Mixed systems
- Supports CCN air terminals using Linkage to BACnet RTU Open Air Source
•
California Title 24
- Includes advanced Fault Detection and Diagnostic Logic for Economizer Operation in
accordance with California Title 24 requirements
•
Equipment Touch
- Carrier Commercial Control’s user interface. The Equipment Touch is a touchscreen
device with a 4.3 in. color LCD display that you connect to the RTU Open (driver v6.00:082 or later) to view or
change its property values, schedule equipment, view trends and alarms, and more, without having to access
the system's server.
The RTU Open’s application supports detailed color graphics, status, properties, alarms, trends, performance,
configuration, and help on the Equipment Touch. In addition, an RTU Open Startup Wizard has specific
screens to facilitate the Carrier Controls installation technician in initially configuring the RTU Open.
For more details about the Equipment Touch, see the Equipment Touch Installation and Setup Guide.
Introduction

Introduction
RTU Open v3 Carrier Proprietary and Confidential CARRIER CORPORATION ©2016
Integration Guide All rights reserved
2

Introduction
RTU Open v3 Carrier Proprietary and Confidential CARRIER CORPORATION ©2016
Integration Guide All rights reserved
3
Safety considerations & handling warning
WARNING
When you handle the RTU Open:
•Do not contaminate the printed circuit board with fingerprints, moisture, or any foreign material.
•Do not touch components or leads.
•Handle the board by its edges.
•Isolate from high voltage or electrostatic discharge.
•Ensure that you are properly grounded.

Wiring inputs and outputs
RTU Open v3 Carrier Proprietary and Confidential CARRIER CORPORATION ©2016
Integration Guide All rights reserved
4
RTU Open Inputs and Outputs Table
Channel
Number
Type
Signal
Function
Part Number
Wire/Terminal
Numbers
Alternate
Terminals
Input 1
AI
4-20 mA
CO2
OAQ
Space Relative Humidity
33ZCT55CO2 33ZCT56CO2
33ZCSPTCO2-01
33ZCSPTCO2LCD-01
w/ 33ZCASPCO2
33ZCSENSRH-02
J4
- 5 & 6
N/A
Input 2
AI
4-20 mA
CO2
OAQ
Space Relative Humidity
33ZCT55CO2 33ZCT56CO2
33ZCSPTCO2-01
33ZCSPTCO2LCD-01
w/ 33ZCASPCO2
33ZCSENSRH-02
J4
- 2 & 3
N/A
Input 3
BI
24 Vac
Compressor Safety **2
Fan Status
Filter Status
Remote Occupancy
Door Contact
N/A
CRSTATUS005A00
CRSTATUS005A00
Field-supplied
Field-supplied
J1
- 2
J5
- 5 & 6
***
Input 4
BI
24 Vac
Safety Chain *
N/A
J1
- 9
N/A
Input 5
BI
24 Vac
Fire Shutdown **1, 2
Fan Status
Filter Status
Remote Occupancy
Door Contact
Field-supplied
CRSTATUS005A00
CRSTATUS005A00
Field-supplied
Field-supplied
J1
- 10
J5
- 3 & 4
***
Input 6
AI
10K
Thermistor
Supply Air Temperature
33ZCSENSAT 33ZCSENDAT
J2 - 1 & 2
N/A
Input 7
AI
10K
Thermistor
Outside Air Temperature
33ZCSENOAT
J2 - 3 & 2
N/A
Input 8
BI
24 Vac
Enthalpy **
Fan Status
Filter Status
Remote Occupancy
Door Contact
33SENTHSW
CRSTATUS005A00
CRSTATUS005A00
Field-supplied
Field-supplied
J2
- 6 & 7
J5
- 1 & 2
***
Input 9
BI
24 Vac
Humidistat **
Fan Status
Filter Status
Remote Occupancy
Door Contact
--HL--38MG-029
CRSTATUS005A00
CRSTATUS005A00
Field-supplied
Field-supplied
J5 - 7 & 8
N/A
Input 10
AI
10K
Thermistor
Space Temperature
33ZCT55SPT 33ZCT56SPT
33ZCT59SPT
J20 - 1 & 2
N/A
Input 11
AI
100K
Thermistor
Space Temperature
Setpoint Adjust
33ZCT56SPT 33ZCT59SPT
J20 - 3 & 4
N/A
Rnet
AI
Zone Temperature
SPS / SPPL / SPP
J13
- 1, 2, 3, 4
N/A
AO - 1
AO
Economizer
Economizer
Actuator-Field-supplied
J2
- 5 & 4
N/A
AO - 2
AO
0-10 Vdc or
2-10 Vdc
Variable Frequency Drive
Field-supplied
J22
- 1 & 2
N/A
BO - 1
BO
N/A - Relay
Fan (G)
N/A
J1
- 4
N/A
BO - 2
BO
N/A - Relay
Heat 2 (W2) Output
N/A
J1
- 5
N/A
BO - 3
BO
N/A - Relay
Heat 1 (W1) Output
N/A
J1
- 6
N/A
BO - 4
BO
N/A - Relay
Cool 2 (Y2) Output
N/A
J1 - 7
N/A
Wiring inputs and outputs

Wiring inputs and outputs
RTU Open v3 Carrier Proprietary and Confidential CARRIER CORPORATION ©2016
Integration Guide All rights reserved
5
Channel
Number
Type
Signal
Function
Part Number
Wire/Terminal
Numbers
Alternate
Terminals
BO - 5
BO
N/A - Relay
Cool 1 (Y1) Output
N/A
J1
- 8
N/A
BO - 6
BO
N/A - Relay
Humidi-MiZer™
N/A
J11
- 7 & 8
N/A
BO - 7
BO
N/A - Relay
Reversing Valve / High
Speed Fan
N/A
J11
- 5 & 6
N/A
BO - 8
BO
N/A - Relay
Power Exhaust
N/A
J11
- 2 & 3
N/A
Legend
AI
-Analog Input
AO
- Analog Output
BI
-Digital Input
BO
- Digital Output
*
Safety Chain Feedback
- 24 Vac required at this wire to provide
Run Enabled
status. Provide a jumper from
J1
- 1 to
J1
- 9 if
no safeties are used. See "To wire inputs and outputs" in the RTU Open Installation Guide for additional information on the RTU
Open wiring harness assembly terminations.
**
Default input function
***
Parallel screw terminal at
J5
(
J5
- 1 =
J2
- 6,
J5
- 3 =
J1
- 10,
J5
- 5 =
J1
- 2) may be used in place of the associated flying leads
at the harness (Part# OPN-RTUHRN). See "To wire inputs and outputs" in the RTU Open Installation Guide for additional
information.
1
N.C. contact must be used as a primary safety device for approved fire shutdown operation. N.O. contact for monitoring only.
2
If a function other the default is used, do NOT connect wires from J1-x.

Communications wiring
RTU Open v3 Carrier Proprietary and Confidential CARRIER CORPORATION ©2016
Integration Guide All rights reserved
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Protocol overview
Protocols are the communication languages spoken by the control devices. The main purpose of a protocol is to
communicate information in the most efficient method possible. Different protocols exist to provide specific
information for different applications.
In the BAS application, many different protocols are used, depending on manufacturer. Different protocols do not
change the function of the controller, but they typically require the owner to change systems or components in
order to change from one protocol to another. The RTU Open is an effective solution to minimize the amount of
controllers that you may need to change in order to communicate with different types of protocols.
You can set the controller to communicate 1 of 4 different protocols:
•BACnet MS/TP (page 7)
•Modbus (page 9)
•N2 (page 12)
•LonWorks (page 14)
The default setting is BACnet MS/TP. Switch 3 (
SW3
) on the board sets protocol and baud rate. Switches
MSB
(
SW1
) and
LSB
(
SW2
) set the board’s network address. See table below for specific switch settings. The third
party connects to the controller through port
J19
for BACnet MS/TP, Modbus, and N2, and through
J15
for the
LonWorks Option Card.
NOTES
•Changing protocol requires no programming or point assignment by the installer or operator.
•Power must be cycled after changing the
MSB
(
SW1
) -
LSB
(
SW2
) settings or connecting the LonWorks Option
Card to
J15
.
SW3 Switch Settings Table
Protocol Selection
Baud Rate
Protocol
DS8
DS7
DS6
DS5
DS4
DS3
DS2
DS1
BACnet MS/TP
(Default)
Master Unused Off Off Off On Off Select Baud Select Baud
Modbus
Slave Unused Off Off On On Off Select Baud Select Baud
N2
Slave Unused Off Off Off On On Off Off
Lonworks
Unused On On Off On Off Off On
Baud Selection Table
Baud Rate
SW3/DS2
SW3/DS1
9,600
Off Off
19,200
On Off
38,400
Off On
76,800
(Default) On On
Communications wiring

Communications wiring
RTU Open v3 Carrier Proprietary and Confidential CARRIER CORPORATION ©2016
Integration Guide All rights reserved
7
BACnet MS/TP
To set up the RTU Open for BACnet MS/TP
Refer to Appendix B (page 46) for the Protocol Implementation Conformance Statement, or download the latest
from BACnet International http://www.bacnetinternational.net/catalog/index.php?m=28.
NOTE
This controller counts as a full load on the MS/TP bus.
1 Turn
off
the RTU Open's power.
NOTE
Changes made to the switches when the controller is on will not take effect until the power is cycled!
2 Using the rotary switches
MSB
(
SW1
) and
LSB
(
SW2
), set a unique MS/TP MAC address for the RTU Open.
Set the
MSB
(
SW1
) switch to the tens digit of the address, and set the
LSB
(
SW2
) switch to the ones digit.
Valid addresses are 01-99.
NOTE
The rotary switches also determine the BACnet device instance of the controller on the BACnet
network. The BACnet device instance is automatically generated based on the scheme 16101xx, where “16”
is the BACnet vendor ID for Carrier Corporation, and xx equals the rotary switch address.
EXAMPLE
To set the controller’s MS/TP MAC address to 01, point the arrow on the
MSB
(
SW1
) switch to 0
and the arrow on the
LSB
(
SW2
) switch to 1. Internally, the BACnet device instance is automatically
generated as 1610101.
3 Set the
SW3
Comm Selector DIP switches
DS1
and
DS2
for the appropriate communications speed (9600,
19.2k, 38.4k, or 76.8k bps).
NOTE
Use the same baud rate and communication settings for all controllers on the network segment. The
RTU Open is fixed at 8 data bits, No Parity, and 1 Stop bit for this protocol's communications.
Baud Selection Table
Baud Rate
SW3/DS2
SW3/DS1
9,600
Off Off
19,200
On Off
38,400
Off On
76,800
On On
4 Set
SW3
Comm Selector DIP switches
DS3
through
DS6
for BACnet MS/TP. See table and example below.
5 Leave
DS7
and
DS8
in the OFF position. These switches are not applicable to MS/TP.
SW3 Protocol Switch Settings for MS/TP
DS8
DS7
DS6
DS5
DS4
DS3
Off Off Off Off On Off

Communications wiring
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Integration Guide All rights reserved
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The following example shows the DIP switches set for 76.8k (Carrier default), and MS/TP.
6 Connect the MS/TP network to the controller's
J19
port. Connect to
Net+
,
Net-
, and
SHLD
.
Wire specifications
○A dedicated 22 AWG shielded twisted pair wire (EIA 485)
○Maximum wire length 2000 feet (610 meters) or 32 nodes
○Devices should be daisy-chained and not star-wired
○Attach the drain/shield wire to both ends of the network segment and through every controller
NOTE
Use the same polarity throughout the network segment.
7 Turn
on
the RTU Open's power.
Troubleshooting BACnet MS/TP
Check the following to troubleshoot your RTU Open:
1 Verify that the BAS and controller are both set to speak the BACnet MS/TP protocol on the Comm Selector
DIP switches
DS3 - DS6
.
2 Verify that the BAS and the controller are both set for the same baud rate:
○Baud rate DIP switches DS2 and DS1
○Obtain a Modstat of the controller. Scroll to the bottom of the page to
Network Communications
to view
the active protocol and baud rate.
3 Verify that the BAS is configured to speak 2-wire EIA-485 to the controller. The BAS may have to configure
jumper or DIP switches on their end.
4 Verify that the BAS and the controller have the same communication settings (8 data bits, No Parity, and 1
stop bit).
5 Verify proper connection wiring between the BAS and the controller.
6 Verify that the controller has a unique MAC address on the MS/TP bus. The controller’s MS/TP MAC address
is set by its rotary address switches.

Communications wiring
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Integration Guide All rights reserved
9
7 Verify that the BAS is reading or writing to the proper BACnet objects in the controller. Refer to Appendix A for
the points list for the controller.
8 Verify that the BAS is sending his requests to the proper MS/TP MAC address of our controller.
9 Present the BAS company with a copy of the controller’s BACnet PICS so that they know which BACnet
commands are supported. The PIC statements are updated regularly. Please refer to the BACnet website
http://www.bacnetinternational.net/catalog/index.php?m=28 for the latest information. In certain
situations, it may be necessary to adjust the MS/TP Protocol timing settings through the Equipment Touch
device.
It may be necessary to adjust the following MS/TP protocol timing settings through the Equipment Touch device:
Max Masters
- defines the highest MS/TP Master MAC address on the MS/TP network.
For example, if there are 3 master nodes on an MS/TP network, and their MAC addresses are 1, 8, and 16, then
Max Masters would be set to 16 (since this is the highest MS/TP MAC address on the network).
This property optimizes MS/TP network communications by preventing token passes and “poll for master”
requests to non-existent Master nodes.
In the above example, MAC address 16 knows to pass the token back to MAC address 1, instead of counting up to
MAC address 127. Each MS/TP master node on the network must have their Max Masters set to this same value.
The default is 127.
Max Info Frames
- defines the maximum number of responses that will be sent when the RTU Open receives the
token. Any positive integer is a valid number. The default is 10 and should be ideal for the majority of applications.
In cases where the RTU Open is the target of many requests, this number could be increased as high as 100 or
200.
NOTES
•MS/TP networks can be comprised of both master and slave nodes. Valid MAC addresses for master nodes
are 0 – 127 and valid addresses for Slave nodes are 0 - 254.
•If the third party attempts to communicate to the controller but does not get a response, make sure the
controller is set as a BACnet MS/TP (m) master. The BACnet software asks the controllers, “Who Is?” This is
to auto-locate devices on the network. Only controllers set as masters will answer this request.
•See Appendix A (page 35) for Points Mapping tables.
Modbus
To set up the RTU Open for Modbus
Refer to Appendix C (page 47) for the Modbus Protocol Implementation Conformance Statement (PICS).
1 Turn
off
the RTU Open's power.
NOTE
Changes made to the switches when the controller is on will not take effect until the power is cycled!
2 Using the rotary switches, set a unique Modbus slave address for the RTU Open. Set the
MSB
(
SW1
) switch to
the tens digit of the address, and set the
LSB
(
SW2
) switch to the ones digit. Valid Modbus slave addresses
are 01-99.

Communications wiring
RTU Open v3 Carrier Proprietary and Confidential CARRIER CORPORATION ©2016
Integration Guide All rights reserved
10
EXAMPLE
To set the controller's Modbus slave address to 01, point the arrow on the
MSB
(
SW1
) switch to 0
and the arrow on the
LSB
(
SW2
) switch to 1.
3 Set the
SW3
Comm Selector DIP switches
DS1
and
DS2
for the appropriate communications speed (9600,
19.2k, 38.4k, or 76.8k bps).
NOTE
Use the same baud rate and communication settings for all controllers on the network segment. The
RTU Open is fixed at 8 data bits, No Parity, and 1 Stop bit for this protocol's communications.
Baud Selection Table
Baud Rate
SW3/DS2
SW3/DS1
9,600
Off Off
19,200
On Off
38,400
Off On
76,800
On On
4 Set
SW3
Comm Selector DIP switches
DS3
through
DS6
for Modbus. See example below.
5 Leave
DS7
and
DS8
in the OFF position. These switches are not applicable to Modbus.
SW3 Protocol Switch Settings for Modbus
DS8
DS7
DS6
DS5
DS4
DS3
Off Off Off On On Off
The following example shows the DIP switches set for 9600 baud and Modbus.
6 Connect the Modbus EIA-485 network to the RTU Open's
J19
port. Connect to
Net+
,
Net-
, and
SHLD
.

Communications wiring
RTU Open v3 Carrier Proprietary and Confidential CARRIER CORPORATION ©2016
Integration Guide All rights reserved
11
Wire specifications
○A dedicated 22 AWG shielded twisted pair wire (EIA 485)
○Maximum wire length 2000 feet (610 meters) or 32 nodes
○Devices should be daisy-chained and not star-wired
○Attach the drain/shield wire to both ends of the network segment and through every controller
NOTE
Use the same polarity throughout the network segment.
7 Turn
on
the RTU Open's power.
Troubleshooting Modbus
Check the following to troubleshoot your RTU Open:
1 Verify that the BAS and controller are both set to speak the Modbus RTU protocol on the Comm Selector DIP
switches
DS3 - DS6
.
2 Verify that the BAS and the controller are both set for the same baud rate:
○Baud rate DIP switches DS2 and DS1
○Obtain a Modstat of the controller. Scroll to the bottom of the page to
Network Communications
to view
the active protocol and baud rate.
3 Verify that the BAS is configured to speak 2-wire EIA-485 to the controller. The BAS may have to configure
jumper or DIP switches on their end.
4 Verify that the BAS and the controller have the same communication settings (8 data bits, No Parity, and 1
stop bit).
5 Verify proper connection wiring between the BAS and the controller.
6 Verify that the rotary address switches are set for the controller's unique slave address.
7 BAS must be reading or writing to the proper point addresses on the controller.
8 BAS is sending requests to the proper slave address of the controller.
NOTES
•Refer to Appendix A (page 35) for the Network Points list.
•Refer to Appendix C (page 47) for the Protocol Implementation Conformance Statement.
Modbus Exception Codes that might be returned from this controller
Codes
Name
Description
01 Illegal Function The Modbus function code used in the query is not
supported by the controller.
02 Illegal Data
Address
The register address used in the query is not supported
by the controller.
04 Slave Device
Failure
The Modbus Master has attempted to write to a non-
existent register or a read-only register in the
controller.

Communications wiring
RTU Open v3 Carrier Proprietary and Confidential CARRIER CORPORATION ©2016
Integration Guide All rights reserved
12
Johnson N2
To set up the RTU Open for N2
Refer to Appendix D (page 49) for the N2 Protocol Implementation Conformance Statement (PICS).
1 Turn
off
the RTU Open's power.
NOTE
Changes made to the switches when the controller is on will not take effect until the power is cycled!
2 Using the rotary switches, set a unique N2 slave address for the RTU Open. Set the
MSB
(
SW1
) switch to the
tens digit of the address, and set the
LSB
(
SW2
) switch to the ones digit. Valid N2 slave addresses are 01-99.
EXAMPLE
To set the N2 slave address to 01, point the arrow on the
MSB
(
SW1
) switch to 0 and the arrow on
the
LSB
(
SW1
) switch to 1.
3 Set the Comm Selector DIP switches
DS1
and
DS2
for the 9600 baud.
NOTE
Use the same baud rate and communication settings for all controllers on the network segment. The
RTU Open is fixed at 9600 baud, 8 data bits, No Parity, and 1 Stop bit.
4 Set
SW3
Comm Selector DIP switches
DS3
through
DS6
for N2. See example below.
5 Leave
DS7
and
DS8
in the OFF position. These switches are not applicable to N2.
SW3 Protocol Switch Settings for N2
DS8
DS7
DS6
DS5
DS4
DS3
Off Off Off Off On On
The following example shows the DIP switches set for 9600 baud and N2.
6 Connect the N2 EIA-485 network to the controller's
J19
port. Connect to
Net+
,
Net-
, and
SHLD
.

Communications wiring
RTU Open v3 Carrier Proprietary and Confidential CARRIER CORPORATION ©2016
Integration Guide All rights reserved
13
Wire specifications
○A dedicated 22 AWG shielded twisted pair wire (EIA 485)
○Maximum wire length 2000 feet (610 meters) or 32 nodes
○Devices should be daisy-chained and not star-wired
○Attach the drain/shield wire to both ends of the network segment and through every controller
NOTE
Use the same polarity throughout the network segment.
7 Turn
on
the RTU Open's power.
Troubleshooting N2
Check the following to troubleshoot your RTU Open:
1 Verify that the BAS and controller are both set to speak N2 protocol on the Comm Selector DIP switches
DS3 -
DS6
.
2 Verify that the BAS and the controller are both set for the same baud rate:
○9600 for N2
○Baud rate DIP switches DS2 and DS1
○Obtain a Modstat of the controller. Scroll to the bottom of the page to
Network Communications
to view
the active protocol and baud rate.
3 Verify that the BAS is configured to speak 2-wire EIA-485 to the controller. The BAS may have to configure
jumper or DIP switches on their end.
4 Verify that the BAS and the controller have the same communication settings (8 data bits, No Parity, and 1
stop bit).
5 Verify proper connection wiring between the BAS and the controller.
6 Verify that the rotary address switches are set for the controller's unique slave address.
7 BAS must be reading or writing to the proper point addresses on the controller.
8 BAS is sending requests to the proper slave address of the controller.
NOTES
•Refer to Appendix A (page 35) for the Network Points list.
•Refer to Appendix D (page 49) for the Protocol Implementation Conformance Statement.

Communications wiring
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14
LonWorks
When you handle the LonWorks Option Card:
•Do not contaminate the printed circuit board with fingerprints, moisture, or any foreign material.
•Do not touch components or leads.
•Handle the board by its edges.
•Isolate from high voltage or electrostatic discharge.
•
Ensure that you are properly grounded.
Refer to Appendix E (page 51) for the LonWorks Protocol Implementation Conformance Statement (PICS).
To set up the RTU Open for the LonWorks Option Card (Part #LON-OC)
1 Turn
off
the RTU Open's power.
NOTES
○Changes made to the switches when the controller is on will not take effect until the power has been
cycled!
○The controller’s rotary address switches are not used when the LON-OC is installed. That’s because each
LON-OC has a 48-bit Neuron ID that makes it unique on the LonWorks network.
2 Set the Comm Selector DIP switches
DS1
and
DS2
on
SW3
for 38.4k Communications speed. This is the
speed at which the LON-OC speaks to the RTU Open. It is fixed at 38.4k.
3 Set the Comm Selector DIP switches
DS3
through
DS6
on
SW3
for LonWorks. See example below.
4 Set the Comm Selector DIP switch
DS7
on
SW3
to the ON position to enable the LON-OC.
5 Leave Comm Selector DIP switch
DS8
on
SW3
in the OFF position since it is not used.
SW3 Protocol Switch Settings for LonWorks
DS8
DS7
DS6
DS5
DS4
DS3
Off On On Off On Off

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The following example shows the DIP switches set for 38.4k baud and the LON-OC enabled.
6 Plug the LON-OC's ribbon cable into Comm Option Port
J15
on the controller. See illustration below.
CAUTION!
The controller must be
OFF
before being connected.
7 Connect the LonWorks network to the LON-OC via the 2-pin
Net
port.
NOTE
The 2-pin
Net
port provides TP/FT-10 channel compatibility. The TP/FT-10 or "Free Topology" network
type is
polarity insensitive
. Use 24 to 16 AWG twisted pair wire.
8 Turn
on
the RTU Open's power.
9 Commission the controller for LonWorks communication. See instructions below.
Commissioning the controller for LonWorks communication
Before a device can communicate on a LonWorks network, it must be commissioned. Commissioning allows the
system integrator to associate the device hardware with the LonWorks system’s network layout diagram. This is
done using the device’s unique Neuron ID.
A network management tool such as Echelon’s LonMaker is used to commission each device, as well as, to assign
addressing. Specific instructions regarding the commissioning of LonWorks devices should be obtained from
documentation supplied with the LonWorks Network Management Tool.

Communications wiring
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Integration Guide All rights reserved
16
When a new device is first commissioned onto the LonWorks network, the system integrator must upload the
device’s External Interface File (XIF) information. LonWorks uses the XIF to determine the points (network
variables) that are available from a device. The RTU Open has a set of predefined network variables. These
variables can be bound or accessed by the Network Management Tool.
The
Browse
feature of the Network Management Tool allows you to read real-time values from the RTU Open. The
Network Management Tool allows you to test integration prior to binding the controller's network variables to other
LonWorks nodes.
Troubleshooting LonWorks
Check the following to troubleshoot your RTU Open:
1 Verify that the BAS and controller are both set to speak the LonWorks protocol by theComm Selector DIP
switches
DS3 - DS6
.
2 Verify that the BAS and the controller are both set for the same baud rate:
○38.4k for LonWorks
○Baud rate DIP switches DS2 and DS1
○Obtain a Modstat of the controller. Scroll to the bottom of the page to
Network Communications
to view
the active protocol and baud rate.
3 BAS must be reading or writing to the proper point addresses on the controller.
4 Verify that the Comm Option Port is enabled on the controller. The Comm Option Port setting must be set via
SW3
(switch
DS7
). It should be in the ON position to enable LonWorks communication.
5 Verify that controller has been properly commissioned onto the LonWorks network. See Commissioning the
controller for LonWorks communication (page 15).
6 Use the
Browse
feature of the network management tool to verify that you can communicate and get real-
time values from the controller before connecting the BAS.
7 Once you have confirmed communications with the controller using the network management tool, connect
the BAS.
8 Verify that the BAS is connected properly to the LonWorks Option Card's 2-wire TP/FT-10 Net port, which is
polarity insensitive. The BAS may have to configure jumper or DIP switches on their end to support TP/FT-10.