Emerson E2 - Manual (Page 62)

6-2 • E2 RX/BX/CX I&O Manual 026-1610 Rev 13 14-SEP-2011
6.1.2 MultiFlex-Plus (+) Board
The MultiFlex-plus board contains a replacement
RS485 transceiver chip that presents less of a load on the
network than a non-plus board. This increases the maxi-
mum number of devices that can be placed on the network,
but not the number of board types an Einstein controller
can communicate with.
The MultiFlex-plus board now accounts for only 1/8
the load of a non-plus board with 32 total devices on the
network (one Einstein controller + 31 boards). This new
conversion allows for the placement of 256 devices on the
network (one Einstein controller + 255 boards). The num-
ber of boards an Einstein controller can support is
increased from 31 up to 255 using MultiFlex-plus boards
only. In other words, the number of I/O net devices are no
longer restricted by the I/O net 31-node limitation.
6.1.2.1 Board Designation
Plus boards are always identified with a plus (+) sign
that appears on the plastic insulating cover on the top of
the board, after the board name.
6.1.2.2 Board Calculations
With X as the number of plus boards and Y as the num-
ber of non-plus boards, use the following equation to
ensure that the number of devices on your network has not
exceeded the maximum load limitation of the network. For
example, if the total number of devices is less than 256,
the maximum load limitation has not been exceeded.
6.1.3 Wiring Types
Retail Solutions specifies all RS485 I/O and MOD-
BUS wiring used by the E2 must be Belden 8641
(24AWG, 300V, Retail Solutions P/N 135-8641); Belden
8761 (22 AWG, 300V not stocked by Retail Solutions); or
a 600V-shielded 22AWG equivalent stocked by Retail
Solutions (P/N 135-0600). These are two-connector
shielded twisted pair cables that support a maximum daisy
chain cable distance of 4000 feet (1219 m) between the E2
and the end device on the network.
6.1.4 The I/O Network Structure
(Daisy Chains)
The RS485 Input/Output (I/O) Network connects all
input and output communication boards together in a sin-
gle open communications loop. This loop, or “daisy
chain,” connects the E2 to multiple input and output com-
munication boards, and terminates at the last input or out-
put board on the network. A diagram of this network
arrangement is shown in Figure 6-1.
6.1.5 Network Noise Minimiza-
tion
Site environments will frequently have numerous
sources of high EMI, or “noise,” that must be accounted
for when routing RS485 network cable. Although the
cable is shielded against noise, the installer must follow
best practices for minimizing network noise.
In general, installers should follow these guidelines
when installing RS485 networks:
PAK 32 MultiFlex PAK rack
controller MultiFlex PAK
CCB 99 CCB case controllers CCBs
ESR 31 MultiFlex ESR valve
controller MultiFlex ESR
CUB-
II 32 Single condensing
unit controller (one
compressor and up to
4 condenser fans) MultiFlex CUB II
NOTE: The MultiFlex-plus board replaces the
old-style MultiFlex boards and is currently
being shipped.
Board
Type
Max # Translation
Boards That
Match Board Type
Table 6-1 - Board Types and Boards Included in Each Type
X + (Y • 8) < 256
Figure 6-1 - I/O Network Configurations