Table of Contents
Advertisement
Installation
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
BACnet MS/TP
(Default)
Modbus
N2
Lonworks
Baud Selection Table
Baud Rate
9,600
19,200
38,400
76,800
(Default)
RTU-MP Controller
DS8
Master
Unused
Slave
Unused
Slave
Unused
Unused
SW3/DS2
SW3/DS1
Off
Off
On
Off
Off
On
On
On
Protocol Selection
DS7
DS6
DS5
DS4
Off
Off
Off
On
Off
Off
On
On
Off
Off
Off
On
On
On
Off
On
Baud Rate
DS3
DS2
DS1
Off
Select
Select
Baud
Baud
Off
Select
Select
Baud
Baud
On
Off
Off
Off
Off
On
5
Advertisement
Table of Contents
