ProSoft Technology MVI94-MCM-MHI - Manual (Page 70)

Reference MVI94-MCM ♦ Flex I/O Platform
User Manual Serial Communications Modbus Communication Module
Page 70 of 109 ProSoft Technology, Inc.
March 29, 2011
5.2.2 RS-232 Configuration/Debug Port
This port is physically an eight-pin, Mini-DIN8F connection. A Mini-DIN8M to
DB9M adapter cable is included with the module. This port permits a PC-based
terminal emulation program to view configuration and status data in the module
and to control the module. Here are the cable pinouts for RS-232 communication
on this port.
5.2.3 RS-485 Application Port(s)
The RS-485 interface requires a single two or three wire cable. The Common
connection is optional, depending on the RS-485 network devices used. The
cable required for this interface is shown below:
Note: Terminating resistors are generally not required on the RS-485 network, unless you are
experiencing communication problems that can be attributed to signal echoes or reflections. In
these cases, installing a 120-ohm terminating resistor between pins 1 and 8 on the module
connector end of the RS-485 line may improve communication quality.