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3-16 Receiving & Installation MN1851
X6 RS232 / 485 Connections
RS232
A null modem cable (also called a modem eliminator cable) must be used to
connect the control and the computer COM port. This will ensure that the transmit
and receive lines are properly connected. Either a 9 pin or a 25 pin connector
can be used at the computer, Figure 3-21. Maximum recommended length for
RS232 cable is 3 ft. (1 meter).
Figure 3-21 9 & 25 Pin RS-232 Cable Connections for UL Installations
25 Pin Connector
9 Pin Connector
Pin
Signal
2 RXD
3 TXD
7 GND
Pin
Signal
2 RXD
3 TXD
5 GND
Null Modem Cable Connections
Control
(DCE)
Computer
COM
Port
(DTE)
RXD
TXD
GND
RXD
TXD
GND
X6
Chassis
Figure 3-22 9 & 25 Pin RS-232 Cable Connections for CE Installations
Null Modem Cable Connections
Control
(DCE)
Computer
COM
Port
(DTE)
RXD
TXD
GND
RXD
TXD
GND
X6
PE PE
Note: For CE installations, connect the overall shield at each end of the cable to PE. The
voltage potential between the PE points at each end of the cable must be Zero Volts.