Carrier RTU-MP, Integration Manual

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RTU-MP Controller 5
Communications wiring - protocols
Protocol Overview
Protocols are the communication languages spoken by control devices. The main purpose of a protocol is to
communicate information in the most efficient method possible. Different protocols exist to provide different
kinds of 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-MP is an effective solution to minimize
the amount of equipment change necessary to communicate with different protocols. Currently, the four most
common protocols are: BACnet, Modbus, N2, and LonWorks.
The RTU-MP can be set to communicate using one of four different protocols: BACnet, Modbus, N2, or
LonWorks. The default setting is BACnet. Switch 3 ( SW3 ) on the board is used to set protocol and baud rate.
Switches 1 and 2 ( SW1 and SW2 ) are used to set the board’s network address. See the table below for the
specific switch settings. The 3rd party connection to the RTU-MP is through port J19 for BACnet, 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 SW1 - SW3 settings.
SW3 Switch Settings Table
Protocol Selection Baud Rate
Protocol DS8 DS7 DS6 DS5 DS4 DS3 DS2 DS1
BACnet MS/TP
(Default)
Unused Master Off Off Off On Off
Select
Baud
Select
Baud
Modbus Unused Slave Off Off On On Off Select
Baud
Select
Baud
N2 Unused Slave 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
Off 9,600 Off
On 19,200 Off
Off 38,400 On
76,800 On
(Default)
On
Installation