RS232 Wiring

Using the CPU 9-pin Serial Port

The RMC100 CPU module has a DTE DB9 serial port labeled "RS-232 Monitor." Both RMCWin and the RMCLink ActiveX Control and .NET Assembly Component use this port. Communication over this port is always at 38400 baud with eight (8) data bits, no parity, and one (1) stop bit.

There are two versions of the serial port for the RMC product. The current style is a male DTE DB9. Early production RMCs have a female DTE DB9. However, because both connectors are DTE, the wiring is the same, so only a gender changer is needed to convert a cable between the two ports.

For details on using the serial port with RMCWin, see Using with RMCWin.

For details on using the serial port with the RMCCOM ActiveX control, see Using with the RMCCOM ActiveX Control.

See also General Wiring Information.

Note: The communication cable attached to the serial port is a potential source of electromagnetic radiation from the RMC. To minimize radiation, use a well-shielded cable that is as short as possible, and route it out the bottom of the module and against the back panel.

DB9 Pin Description

Pin	Function
2	Receive
3	Transmit
5	Common

Cable Recommendations for Male DB9 Connector

The following options are available for the cable between the PC and the RMC serial port:

Generic null-modem (female on both ends) serial cable
Allen-Bradley PLC serial cable
Modicon Modbus cable with a 9-pin male-to-female gender changer
Siemens SIMATIC 505 Programmable Controller serial cable
You can use one of the following diagrams to build an RS232 cable:

$image\ebx_-480793945.gif$

Any other cable you have will work if you can verify that pins 2, 3, and 5 on the RMC-end of the cable are connected as shown in the above diagram. An Ohmmeter or continuity checker will work for verifying the cable connections.

Cable Recommendations for Female DB9 Connector (older)

The recommendations for the older female DB9 connector are the same as for the male DB9 connector, but the gender on the RMC-end of the cable must be reversed:

Generic null-modem (female on both ends) serial cable with a 9-pin female-to-male gender changer
Allen-Bradley PLC Serial Cable with a 9-pin female-to-male gender changer
Modicon Modbus cable
Siemens SIMATIC 505 Programmable Controller Serial Cable with a 9-pin female-to-male gender changer
You can build an RS232 cable using the diagram above, except the gender of the RMC-end connector should be reversed.
Any other cable you have will work if you can verify that pins 2, 3, and 5 on the RMC-end of the cable are connected as shown in the above diagram. An Ohmmeter or continuity checker will work for verifying the cable connections.