- Emerson Remote Terminal Unit Instruction Manual

2-14 / Installation & Operation CI-ControlWave Express
Table 2-4 - RS-485 Network Connections
(see Table 2-3C ControlWave Express RS-485 Port Pin # Assignments)
From
Master
To 1st
Slave
To nth
Slave
TXD+ RXD+ RXD+
TXD− RXD− RXD−
RXD+ TXD+ TXD+
RXD− TXD− TXD−
GND/ISOGND* GND/ISOGND* GND/ISOGND*
* ISOGND with Isolated RS-485 Ports Only!
Note: Pins 1, 2, 3, 4 & 9 of BBI Series 3305, 3310, 3330, 3335 & 3340 RTU/DPC RS-485 Comm.
Ports are assigned as follows: 1 = TXD+, 2 = TXD-, 3 = RXD+, 4 = RXD- & 9 = ISOGND.
Table 2-5 - CPU/System Controller Bd. Switch SW3 Assignments
RS-485
Loopback & Termination Control for COM3
SWITCH
#
RS-485 Function
Switch ON
Setting
SW3-1 TX+ to RX+ Loopback/2-Wire
ON – 2-Wire Operation or Loopback Enabled
OFF – 4-Wire Operation & Loopback Disabled
SW3-2
TX− to RX− Loopback/2-Wire
ON – 2-Wire Operation or Loopback Enabled
OFF – 4-Wire Operation & Loopback Disabled
SW3-3 100 Ohm RX+ Termination ON – End Nodes Only
SW3-4
100 Ohm RX− Termination
ON – End Nodes Only
SW3-7 RX+ Bias (End Nodes/Node)
ON – 4-Wire = Both End Nodes
2-Wire = One End Node Only
OFF – No Bias
SW3-8
RX− Bias (End Nodes/Node)
ON – 4-Wire = Both End Nodes
2-Wire = One End Node Only
OFF – No Bias
SW3-5 & SW3-6 Not Used
2.3.3.4 Ethernet Port
ControlWave Express CPU/System Controller Boards can contain one Ethernet Port that
utilizes a 10/100Base-T RJ-45 modular connector (J1) and typically provides a shielded
twisted pair interface to an Ethernet Hub.
A typical Ethernet Hub provides eight (8) 10/100Base-T RJ-45 Ports (with Port 8 having the
capability to link to another Hub or to an Ethernet communications port). Both ends of the
twisted pair Ethernet cable are equipped with modular RJ-45 connectors. These cables have
a one-to-one wiring configuration as shown in Figure 2-8. Table 2-6 provides the
assignments and definitions of the 8-pin 10/100Base-T connector.
It is possible to connect two nodes in a point-to-point configuration without the use of a
Hub. However, the cable used must be configured such that the TX+/- Data pins are
connected to the RX+/- Data pins (swapped) at the opposite ends of the cable (see Figure 2-
7).
The maximum length of one segment (CPU to Hub) is 100 meters (328 feet). The use of
Category 5 shielded cable is recommended.
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