Rockwell Automation 1771-DA,D17716.5.13 U MNL 1771-DA ASCII I/O MODULE - Manual (Page 161)

Troubleshooting
Chapter 7
7Ć2
Feature Invalid Setting or Range Word (Bit)
EndĆofĆstring delimiter IW3(10Ć16) Same value as IW4(10Ć16)
when you use IW3 and
IW4
3A hex, when you do not
use IW4 (3A is default of
IW4(10Ć16) when IW4 is
not used)
BCD delimiter IW4(10Ć16) No value entered when
using all four initialization
words (00 hex is an illegal
BCD delimiter value)
There are three LED status indicators on the front of the module. They
are labeled:
FAULT
BUFFER FULL
CHANNEL ACTIVE
The location of these LED indicators and how you interpret them is
described in Figure 6.1.
Figure 6.1
Status Indicators
FAULT Ć This red indicator illuminates when the module
detects an internal hardware fault. It is normally off.
BUFFER FULL Ć This yellow indicator illuminates when the input buffer is
full. It must be reset by program logic using CW1(03).
CHANNEL ACTIVE Ć This green indicator illuminates when an ASCII
device is turned on and is properly connected to the INTERFACE port.
The module examines only the received data line for channel active
indication. This indicator does not monitor communication between the
processor and the ASCII module.
NOTE: In RSĆ232ĆC and current loop modules, disregard the CHANNEL
ACTIVE indicator when in simplex mode of transmission. The simplex
write mode disregards the status of the receive line, which is indicated by
the CHANNEL ACTIVE indicator.
ASCII
I/O
FAULT
BUFFER
FULL
CHANNEL
ACTIVE
How You Interpret Status
Indicators