Measurement Computing PCI-COM422/485 - Manual (Page 9)

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2.4.3 TEST THE COM PORTS FOR PROPER OPERATION (COMAPP.EXE)
An application is provided that allows you to test your installation by communicating with another
RS-422 or RS-485 serial port. This test application is called ComApp.exe, and was installed during your
driver installation procedure. ComApp is a simple ASCII terminal emulator that automatically sends
whatever you type on the keyboard over the selected COM port, and automatically displays the data the
COM port receives.
You may use this application to test between two ports on the same PC, or install it on two PCs and test
communication between them. If you are installing a multi-port board, or you have a free RS-422 or RS-
485 port in addition to the one you are adding with the PCI–COM board, you can use the first method by
running two instances of ComApp on the same PC.
If your COM port is connected to a simple ASCII controlled device, use ComApp to test for proper operation simply
by typing one or more commands, and watching how the external device responds.
To launch ComApp.exe you may either find the file using your explorer and double-click on it or, starting with your
Windows Start button, follow this order:
Start
Î Programs Î ComputerBoards Î ComApp
Note: The above sequence assumes that the application was installed in the default “ComputerBoards”
folder. If you selected a different folder during installation then replace “ComputerBoards” with your
folder name.
If you have a multi-port board, you can make a quick port communication test by connecting one port to another,
and sending/reading data between the two ports.
To do this test you will need to connect the two ports together. In RS422 mode the receive pair (Pins 6 and 7) must
be connected to the transmit pair (Pins 8 and 9).
Port 1 Port 2
6 --------------------------- 8
7 --------------------------- 9
8 --------------------------- 6
9 --------------------------- 7
RS485 is a half-duplex protocol and thus transmits and receives over the same pair of wires. For RS485 the
following connection will suffice to test the installation.
Port 1 Port 2
8 ---------------------------- 8
9 ---------------------------- 9
This serves to connect the transmit pins from one port to the receive pins of the other and vice versa. To perform the
test, follow the instructions below:
1. Connect the two ports as indicated above
2. Launch the ComApp program (as described above)
3. Select the Settings menu block and configure the first port. Figure 2-4 shows the settings dialog that will
be displayed.