Ect Modbus Networking To E2S; Com Port Associations - E2 Versions; Com Port Associations - E2 Versions 4.2 And Above - Emerson Dixell XR75CX Series Installation And Operation Manual

18 ECT MODBUS
Networking to
E2s
18.1. COM Port Associations
- E2 Versions 3.xx and
Below
E2 PIB COM PORT ASSOCIATIONS
E2 Enclosure (Right Side)
E2 Modem/Expansion
COM Card Mounted
Above PIB
RS232
COM3
Plug-In
Modem
Card
RS485 COM Card
(2 Connectors)
POWER INTERFACE BOARD
COM4
Serial Device
RS485 COM Port
(2 Connectors)
COM2
Figure 18-1 - Location of E2 COM Ports (E2 versions 3.xx and
Below)
Connecting a XR75CX 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.
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 XR75CX 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
22 • XR75CX I&O Manual
COM6
COM1
RS485
Serial Device
RS232 Port
(PIB)
configured in E2 General Services
Se
rial 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.
E2
Figure 18-2 - MODBUS Networking
18.2. COM Port Associations
- E2 Versions 4.2 and
Above
E2 PIB COM PORT ASSOCIATIONS
E2 Enclosure (Right Side)
Plug-In
Modem
Card
Serial Device
RS485 COM Ports
COM2

Figure 18-3 - Location of E2 COM Ports - E2 PIB Board (E2
versions 4.2 and above)
An E2 has three COM ports that can be assigned for 
MODBUS communication (COM2). COM ports can only
be used for one function; in other words, if COM2 is set up

(
TERMINATED,
BIASED
(ALL 3 JUMPERS
IN UP POSITION)
XR75CX
XR75CX XR75CX
#1 #2
#1
Serial Device
RS232 Port
COM3
POWER INTERFACE BOARD
(PIB)
COM6 COM4
026-1210 Rev 4
, 
XR75CX
#3
COM1