do not need to be physically connected on the bus in
their numerical device address order.
5. Write each field controller’s device address on the
white label below the DIP switch block on the
controller’s cover.
Refer to the
MSTP Communications Bus Technical
Bulletin (LIT-12011034)
for more information on field
controller device addresses and how to set them on
MSTP Buses.
show and describe the valid FC Bus and SA Bus
device addresses for Johnson Controls MSTP
communications bus applications.
Table 6: FC Bus Device Address Descriptions
Address Description
Device
Address
Reserved for FC Bus Supervisory Controller
(not valid for field controllers).
0
(Switch 128
OFF)
Reserved for peripheral devices (not valid for
field controllers).
1 to 3
(Switch 128
OFF)
Valid for MSTP Master field controllers on a
hard-wired
SA Bus or FC Bus.
4 to 127
(Switch 128
OFF)
Setting the N2 Controller Address to
be Greater than 127
N2-configured controllers support the full range of
possible N2 device addresses provided by the N2 protocol
standard (1-255). However, these controllers require
special configuration for addresses above 127.
Use the following instructions for controller addresses
greater than 127. Prior to performing this procedure, be
sure the controller has been converted from BACnet to
N2 protocol first. Refer to the
Modernization Guide for
Legacy N2 Controllers (LIT-12012005)
for more
information.
1.
Disconnect the 24 VAC supply from the controller.
2.
Remove the FC Bus connector from the controller.
3.
Set the address switch set to the desired N2 address.
4.
Set the address switch segment labeled 128 to OFF.
5.
Reconnect the 24 VAC supply to the controller.
6.
Using an SA bus connection, download the firmware
and controller application file. The download process
asks to confirm switching the communication protocol
to N2.
7.
Click
OK
.
8.
After the download is finished, disconnect the 24
VAC supply to the controller.
9.
Set the address switch segment labeled 128 to ON.
10. Reattach the FC Bus connector to the controller.
11. Reconnect the 24 VAC supply to the controller.
Setting the EOL Switch
Each field controller has an EOL switch, which, when set
to ON (up), sets the field controller as a terminating device
on the bus. See (
) for the EOL switch location
on the field controller. The default EOL switch position is
OFF (down). The amber EOL LED illuminates to show
the EOL is active.
Figure 10: EOL Switch Positions
To set the EOL switch on a field controller:
1. Determine the physical location of the controller on
the SA or FC Bus.
2. Determine if the controller must be set as a
terminating device on the bus.
Note:
The EOL termination rules for SA Buses and
FC Buses are different. Refer to the
MSTP
Communications Bus Technical Bulletin
(LIT-12011034)
for detailed information
regarding EOL termination rules and EOL
switch settings on SA and FC Buses.
3. If the controller is a terminating device on the FC Bus,
set the EOL switch to ON. If the controller is not a
terminating device on the bus, set the EOL switch to
OFF.
Note:
When the EOL switch is set to ON, the LED
light on the face of the controller is illuminated.
16
VMA1615 and VMA1630 Variable Air Volume Controllers Installation Instructions