Enabler Card Loopback Diagnostics

The Enabler Card includes a special diagnostic feature called a loopback test. The loopback test provides a way to ensure the Enabler ports are able to transmit and receive data correctly. There are two tests, one for the RS-232 ports and one for RS-485.

To perform these tests, you need to make special cables connecting various transmit and receive pins on The Enabler Card's DB25 connector.

Important Note: If the Enabler card to be tested is in a PC with Enabler software installed, then you need to do the following before the test:

Stop the Pump Server
Don't restart the pump server until the tests are completed.
Reset the Enabler card
This is done by connecting pins 1 and 2 on the test header.

RS-232 Loop Back

This test verifies that the four RS-232 ports on the PCI card are operating correctly.

To make an RS-232 Loop back connector the following pin assignments are required on a Female DB25 Connector.

Connect pin 2 to pin 6
Connect pin 3 to pin 20
Connect pin 5 to pin 8
Connect pin 11 to pin 22

To perform an RS-232 loop back test, plug the RS-232 test connector into the Enabler PCI card (in a PC). Then connect pins 7 and 8 on the Enabler PCI test connector using a jumper. While the jumper is in place the test will be repeated every second.

Successful RS-232 loopback test

For each cycle of the test, both red and green LED's for all four ports will flash (it is a very fast sequence).
If the test passes, the Red Heartbeat LED (closest to the DB25) will toggle (on to off, or off to on)
If the test fails the Red Heartbeat LED will not flash.
Test sequence will repeat.

RS-485 Loop Back

This test verifies that the three RS-485 ports (Port 1, 2 and 3) on the PCI card are operating correctly. The LEDs for port 4 will not flash as part of this test, because port 4 is RS-232 only.

To make an RS-485 Loop back connector the following pin assignments are required on a Female DB25 Connector.

Connect pin 14 to 16 and then to 18
Connect pin 15 to 17 and then to 19

To perform an RS-485 loop back test, plug the RS-485 test connector into an Installed Enabler PCI card (in a PC). Then connect pins 5 and 6 on the Enabler PCI test connector using a jumper. While the jumper is in place the test will be repeated every second.

Successful RS-485 loopback test

If the test fails the Red Heartbeat LED (closest to the DB25) will not flash.
If the test is successful the LED's will flash in the following sequence:
- Port 1 Red, Port 2 Green and Port 3 Green
- Port 1 Green, Port 2 Red and Port 3 Green
- Port 1 Green, Port 2 Green, and Port 3 Red
If the test passes, the Red Heartbeat LED (closest to the DB25) will toggle (on to off, or off to on)
If the test fails the Red Heartbeat LED will not flash.
Test sequence will repeat.

Related information: About Enabler LEDs