Rockwell Automation 2707-L40X_L8X_V40X DTAM Plus Operator Interface Module Installation Instructions - Manual (Page 104)

Chapter 7
Troubleshooting and Maintenance
7–16
Only available on the RS-485 Comm port version. Use the TXEN test to
verify the transmit enable line at the RS-485 communications port.
The TXEN test requires a loopback connector with an LED. You can
construct a simple loopback connector as shown below:
DB9 Female
1 Data Out -
2 Data Out +
3 Data In -
4 Data In +
5 Signal Ground
6 Transmit Enable
7 Not Used
8 Signal Ground
9 Shield
Pin Signal Name
RS-485 Comm Port Only
Connects pins 1 !3
and pins 2 ! 4
LED and 750 W resistor
between pins 2-4 and 6
Loopback Connector
750
W
LED
To test the transmit enable line:
1. Use the [NEXT] or [PREV] keys to display TXEN/ & Alarm Test on the
test selection screen.
DTAM Plus Diagnostic
NEXT to Select Test
ENTER To Initiate
TXEN/ & Alarm
2. Press [ ] to initiate the test.
The following screen appears.
Toggling TXEN Line
A stable Alarm LED
Press ENTER
The Alarm LED flashes at approximately 1 second intervals indicating
that the transmit enable line is functioning properly.
3. Pressing [ ] terminates the TXEN/ & Alarm test.
The next test selection screen is displayed.
DTAM Plus Diagnostic
NEXT to Select Test
ENTER To Initiate
Reset DUT
4. To terminate the test function , press the [NEXT] or [PREV] keys to
display Reset DUT in the test selection area. Press [ ] to reset the
DTAM Plus.
TXEN Test