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on manufacturer. Protocols do not change the functi on of
a controller; just make the front end user different.
The RTU--MP ca n be set to communicate on four different
protocols: BACnet, Modbus, N2, and LonWorks. 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 Fig. 63 for the switch setting
per protocol. The 3rd party c onnection to t he RTU--MP is
through plug J19.
NOTE: Power must be cycled after changing the SW1--3
switch settings.
BACnet
MS/TP
BACnet Master Slave/Token Passing (MS/TP) is used for
communicating BACnet over a sub--network of
BACnet--only cont rollers. This is the default Bryant
communications protocol. Each RTU--MP module a cts as
an MS/TP Master. The speed of an MS/TP network can
range from 9600 to 76.8K baud. Physica l Addresses can
be set from 01 to 99.
Modbus
The RTU--MP module can speak the Modic on Modbus
RTU Protocol as described in the Modicon Modbus
Protocol Referenc e Guide, PI--MBUS--300 Rev. J.The
speed of a Modbus network c an range from 9600 to 76.8K
baud. Physical Addresses can be set from 01 to 99.
Johnson
N2
N2 i s not a standard protocol, but one that was created by
Johnson Controls, Inc. that has been made open and
avai lable to the public. The speed of N2 network is
limited to only 9600 baud. Physical addresses can be set
from 01 to 99.
LonW
orks
LonWorks i s an open protocol that requires the use of
Eche lon’s Ne uron microprocessor to encode a nd decode
the LonWorks packets. In order to reduce the cost of
adding that hardware on every module , a separate
LonWorks Option Card (LON--OC) was designed to
connect to the RTU--MP.
This accessory card is needed for LonWorks and has to be
ordered and connected using the ribbon cable to plug J15.
The RTU--MP’s baud ra te must be set to 38.4k to
communicate with the LON--OC. The address switches
(SW1 & SW2) are not used with L onWorks.
Local
Access
BACview
6
Handheld
The BACview
6
is a keypad/display interface used to
connect to the RTU--MP to access the control information,
read sensor values, and test the RTU, see Fig. 64. This is
an accessory interface that does not come with the MP
controller and can only be used a t the unit. Connect the
BACview
6
to the RTU--MP’s J12 local access port. There
are 2 password protected levels in the display (User and
Admin). The user pa ssword is defaulted to 0000 but can
be changed. The Admin password is 1111 and cannot be
changed. There is a 10 minute auto logout if a screen is left
idle. Contact your Bryant applications engineer for details
on navigati on and screen content.
Virtual BACview
Virt ual BACview is a freeware computer program that
functions as the BACview
6
Handheld. The USB Link
interface (USB--L) is required to connect a com puter to
the RTU--MP board. The link cable connects a USB port
to the J12 local access port. This program functions and
operates identical to the handheld.
SW3 Protocol Selection
PROTOCOL DS8 DS7 DS6 DS5 DS4 DS3 DS2 DS1
BACnet MS/TP
(Master)
Unused OFF OFF OFF ON OFF Select Baud Select B aud
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 OFF
NOTE:
DS = Dip Switch
BACnet MS/TP SW3 example shown
Baud Rate Selections
BAUD RA TE DS2 DS1
9600 OFF OFF
19,200 ON OFF
38,400 OFF ON
76,800 ON ON
C07166
Fig. 63 -- RTU--MP SW3 Dip Switch Settings
548J