DIP switch block at the top of the controller (Figure
1). Device addresses 1 through 253 are the valid N2
addresses for these N2 controllers.
Valid MS/TP addresses for wired controllers are
4 through 127. For wireless controllers, valid
addresses are 132 through 254 (132 [132-128=4]
through 254 [254-128=126]).
For wireless controllers, the address 120 through
127 are used by the ZigBee
®
Coordinator. This may
cause a smaller field device range.
If the VMA18 Series controller may eventually be
converted to MS/TP, use addresses 4 through
127 for a wired VMA controller or addresses 132
through 253 for a future wireless VMA controller, if
possible. Using these addresses simplifies the MS/
TP conversion process.
Note:
Metasys
field controllers ship with
Switch 128 ON and the remaining address
switches OFF rendering the controllers wired
subordinate devices, which do not operate
on MS/TP buses, but do not interfere with
bus operation. Set a valid and unique device
address on the field controller before applying
power to the controller on the bus.
The DIP switch block (Figure 14) has eight switches
numbered 128, 64, 32, 16, 8, 4, 2, and 1. Switches 128
through 1 are device address switches.
Figure 14: Device address switches set to 21
To set the device addresses on a
Metasys
field
controller:
1. Set all of the switches on the field controller’s
device address DIP switch block (128 through 1)
to OFF.
2. Set one or more of the eight address switches
(128 through 1) to ON, so that the sum of the
switch numbers set to ON equals the intended
device address. Set the highest number switch
that is less than or equal to the intended device
address to ON. Then continue setting lower
numbered switches until the total equals the
intended address. For example, if the intended
device address is 21, set Switch 16 to ON first,
then set Switch 4 to ON, followed by Switch 1
3. Set a unique and sequential device address
for each of the field controllers connected on
the N2 bus, starting with device address 1.
To ensure the best bus performance (if the
protocol is changed to BACnet MS/TP), set
sequential device addresses with no gaps in
the device address range (4, 5, 6, 7, 8, 9, and
so on). The field controllers do not need to
be physically connected on the bus in their
numerical device address order.
4. Write each field controller’s device address on
the white label below the DIP switch block on
the controller’s cover.
Refer to the
N2 Communications Bus Technical Bulletin
(LIT-636018)
for more information on field controller
device addresses and how to set them on N2 buses.
Setting the EOL switch
Each field controller has an EOL (End of Line) switch,
which, when set to ON (up), sets the field controller
as a terminating device on the bus. See Figure 1 for
the EOL switch location on the field controller. The
default EOL switch position is OFF (down).
Figure 15: EOL switch positions
To set the EOL switch on a field controller:
1. Determine the physical location of the field
controller on the N2 or FC Bus.
2. Determine if the field controller must be set as
a terminating device on the bus.
VMA1826/1832 VAV Controller Installation Guide
20
