COM Port Associations - E2 Versions 3.xx and Below
ECT MODBUS Networking to E2s • 37
22 ECT MODBUS
Networking to
E2s
Connecting a XM670 - XM679 controller to an E2
requires the E2 to be version 2.84 or above. Contact
Emerson for upgrade information if the controller is a
version before 2.84.
22.1.COM Port Associations
- E2 Versions 3.xx and
Below
An E2 has up to three COM ports that can be assigned
for MODBUS communication: COM2, an RS485
port on the E2 power interface board, and COM4 and
COM6, which are optional ports requiring expansion
cards.
COM4 is recommended for MODBUS
connection of XM670 - XM679 units.
COM ports can only be used for one function; in other
words, if COM2 is set up as the I/O network, you
cannot connect MODBUS devices to COM2. Ensure
your E2 is equipped with an RS485 COM Card
(P/N
637-4890)
and configured in E2 General Services
(
,
Serial
tab)
to enable COM4 or an
E2 Expansion COM Card
(P/N 637-4871)
to enable
COM6.
Connect the MODBUS network cable to the three-
terminal connector on the COM port you wish to
assign as MODBUS. Reverse polarity of +/- on
RS485 cable from E2 to the device.
22.2.COM Port Associations
- E2 Versions 4.0 and
Above
Figure 22-1 - Location of E2 Com Ports - E2 PIB Board (E2
versions 3.xx and Below)
E2 PIB COM PORT ASSOCIATIONS
COM1
COM4
COM6
COM2
Serial Device
RS485 COM Port
(2 Connectors)
RS485 COM Card
(2 Connectors)
Serial Device
RS232 Port
POWER INTERFACE BOARD
(PIB)
E2 Modem/Expansion
COM Card Mounted
Above PIB
Plug-In
Modem
Card
COM3
E2 Enclosure (Right Side)
RS485
RS232
Figure 22-2 - MODBUS Networking
Figure 22-3 - Location of E2 Com Ports - E2 PIB Board (E2
versions 4.0 and Above)
E2
XM670/
XM679
#1
TERMINATED,
BIASED
(ALL 3 JUMPERS
IN UP POSITION)
XM670/
XM679
#2
XM670/
XM679
#3
E2 PIB COM PORT ASSOCIATIONS
COM1
Serial Device
RS232 Port
POWER INTERFACE BOARD
(PIB)
E2 Enclosure (Right Side)
COM2
COM6
COM4
Serial Device
RS485 COM Ports
Plug-In
Modem
Card
COM3
