Communication Driver: TCP/IP-to-RS232 Bridge Configuration

Note: This communication driver requires RMC100 CPU firmware dated 20010522 or later.

The main steps to configuring a TCP/IP-to-RS232 Bridge communication path are as follows:

Obtain a TCP/IP-to-RS232 Bridge

There are a number of TCP/IP-to-RS232 bridge devices available. A search on the Internet for "Ethernet to Serial Converter" should find a number of manufacturers providing these devices. The RMC has been tested with the Lantronix (www.lantronix.com) UDS-10. If multiple RMCs will be hooked up using the same method, it may be worth investing in a multi-port bridge, so that a single bridge can handle several RMCs.

Connect the Bridge to the Ethernet Network

How this is done depends on the particular bridge device, but in most cases will involve using a CAT5 Ethernet cable to connect the bridge to a hub or switch on the LAN that will be used.

Connect the Bridge to the RMC

The bridge will be connected to the RMC's "RS-232 Monitor" serial port using an RS232 cable. The RMC's serial port is DTE. Therefore, if the port on the bridge is DTE, then a cross-over cable should be used; otherwise a straight-through cable should be used. See RS232 Wiring for details.

Configure the TCP/IP-to-RS232 Bridge

Most of the work in setting up this driver involves configuring the bridge device. These bridges are typically designed to be very flexible, and as a result can be fairly confusing to set up. The following serial settings must be used to communicate with the RMC:

Signals: RS232

Baud Rate: 38400

Data Bits: 8

Parity: None

Stop Bits: 1

Flow Control: None

In addition to these basic serial settings, there are often many other options for the serial interface. The bridge should act in Server mode. Therefore, it will not need to deal with initiating connections or setting up a specific remote IP address.

The second main set of settings you will need to configure in the bridge is the TCP/IP interface. This will include the following settings:

IP Address, Subnet Mask, and Default Gateway: The same guidelines laid out in Understanding IP Addressing for selecting an RMC ENET's IP parameters apply when selecting a bridge's IP parameters. The IP address entered for the bridge will need to be entered in RMCWin, as described below.

TCP/UDP: RMCWin will open a TCP connection. Therefore, if you are given the option of selecting between TCP and UDP, select TCP.

TCP/UDP Port: The TCP/UDP port number set up for the bridge's serial port is really irrelevant, as long as the same value is entered in the RMCWin TCP/IP-to-RS232 Bridge driver configuration screen.

Configure RMCWin for the TCP/IP-to-RS232 Bridge Driver

After you have set up the bridge, it is time to select and configure the TCP/IP-to-RS232 Bridge driver in RMCWin.

To configure the TCP/IP-to-RS232 Bridge communication driver:

Start RMCWin.
On the main window's Tools menu, click Options, and then click the Communication tab.
You can also double-click the Communication pane of the main window's status bar, or right-click this pane and then click CommunicationOptions from the shortcut menu. This is the pane that displays the current communication path and state (e.g. "COM1: Offline").

Under Communication Driver, click TCP/IP-to-RS232 Bridge.
Select the desired settings described below.
Click OK.

The TCP/IP-to-RS232 Bridge driver settings offered in this dialog box are listed below:

Target IP Address text box:
Type the IP address of the TCP/IP-to-RS232 bridge device whose serial port is connected to the RMC you want to communicate with. You can also use the drop-down list to select from the last several IP addresses you have entered. Guidelines for setting up the bridge device were given above.

TCP Port text box:
The TCP/IP-to-RS232 bridge device can typically be configured to respond on any one TCP port. The port that the bridge is configured to use and the TCP port entered in this text box must match. Which port is used is usually not important, as long as it is between 1024 and 65535. In most cases, you should be able to use the default TCP port on the bridge device. Guidelines for setting up the bridge device were given above.

Communications Update Rate slider:
This slider adjusts a delay that is inserted between transactions between RMCWin and the RMC. The only purpose for this control is to decrease the load on slower PCs; the RMC can handle any of the communication speeds. If this software seems to slow down Windows, move this slider closer to Slow.
Move the slider toward Slow to decrease the load on the PC, and toward Fast to increase the load on the PC.

Note: This setting is ignored while reading up a plot; no delay is used.