The following test verifies the RS-485 configured ports are operating correctly.
One of the following cables:
An RS-485 DB9F to DB9F straight-through cable
An RS-485 RJ45 to RJ45 straight-through cable.
An Ethernet patch cord.
Two RS-485 ports configured by the driver.
To build your own RS-485 DB9F to DB9F straight-through cable, wire the following pins together:
Pin 3 to pin 3
Pin 7 to pin 7
To build your own RS-485 RJ45 to RJ45 straight-through cable, wire the following pins together:
Pin 1 to pin 1
Pin 4 to pin 4
The following procedure describes how to test RS-485 ports:
Start the WCom2 Test Terminal and open the two RS-485 ports. (See Starting Test Terminal for more information on starting test terminal.)
Attach the straight-through cable to both RS-485 ports.
Select one of the open ports and:
Click the Receive
Test Data button on the port window toolbar
to disable receive test data. Ready
should appear in the port window status bar.
Click the Send
Test Data button on the port window toolbar
to send test data from that port. Sending
should appear in the port window status bar.
Note: RS-485 is a half-duplex
protocol and is unable to send and receive data on the same port at the
same time. You must
specify one port to send data and another port to receive data.
Select the other open port and click the Receive Test Data button
on the port window toolbar to receive test data from the other open port.
Receiving should appear in the
port window status bar. This is a pass/fail test that checks all modem
control signals.
Pass - If the straight-through cable is in place and the port is working correctly, the test data should be echoed to the screen. You should see the alphabet scrolling in a sawtooth pattern (incrementing by one letter for each line of data received until it reaches the letter Z and then it repeats until you stop the test).
Fail - If the straight-through cable is not in place or the port is not working correctly, no data or garbled data is echoed to the screen. This indicates the RS-485 port is not working.
To stop the test data stream, click the Send Test Data button
in the sending port and the Receive Test
Data
button in the receiving port. Ready should appear in the port window
status bar for each port.
Select File > Exit to close the Test Terminal.