Rockwell Automation 2755 AtomScan Bar Code Reader - Manual (Page 103)

7–2 Maintenance and Troubleshooting
Publication 2755-6.9
The following table provides a list of the most common operating
problems, probable causes, and corrective actions.
Problem Probable Cause (s) Corrective Action
1. Host cable defective or
not wired properly.
1. Check cable connections and wiring.
Menus do not
display when
configuration 2. Wrong configuration
command (or lower
case d) entered.
2. Verify that a <D> serial command (with an
upper case D) is being entered.
configuration
command is sent.
3. Reader configuration
settings do not match
host’s.
3. Reset reader to default and/or match host
settings with reader’s.
Getting
unintelligible code.
1. Host and reader baud
rates or parity not
matched.
1. Check baud rates and parity and change to
match the host’s settings.
1. Wrong label type or
different label type being
scanned than that
enabled in firmware.
1. Check label configuration settings to be certain
that they match the label type being scanned.
If label type is in doubt, enable
Autodiscriminate All Codes (<P> command).
Also ensure that fixed length and check sums,
if enabled, are set correctly.
Menu display but
no decode rate in
decode rate test
2. Incorrect label range or
label too long to be
totally covered by scan
beam.
2. Reposition label and check the decode rate
(<C> command).
decode rate test
(<C>).
3. Poor label quality. 3. Try a readable label. (<C>).
4. Excessive ambient light,
sunlight, or strobes.
4. Shield the bar code and/or scan head to verify
that excessive light is not the problem.
5. Object detector or
another reader is
interfering with reads.
5. Remount, eliminate interference, or shielding.
(Many object detectors emit pulsed infrared
signals that can seriously degrade the decode
rate if they shine into the reader or onto
the bar code label when it is being read.)
Low decode rates
during decode rate
test (<C>). 1. Poor label, range,
placement, etc.
1. Use better quality labels, place reader closer
to label, etc.
1. Object detector not
positioned properly.
1. Ensure read cycle is active during the time the
label is in the scan line.
2. End of Read Cycle not
properly defined.
2. Ensure that the proper End of Read Cycle is
defined in reader configuration.
Decode rate okay
3.. Reader not triggered
when in external mode.
3. Ensure trigger device is operating properly.
Also do a Decode Rate Test <C>. If it reads
successfully, the problem is triggering.
Decode rate okay
but not getting any
output (including
no reads) in
triggered mode.
4. Reader not triggered
when in serial mode.
4. Ensure that correct serial trigger character is
entered with start/stop characters (a left angle
bracket < (unless redefined) and a right angle
bracket >).
5. Label misaligned or
reflecting direct laser
light.
5. Ensure the label is not excessively skewed,
tilted, or otherwise disoriented. Ensure the bar
code is in the scan line when it is supposed to
be. Ensure that the bar code is pitched or
skewed slightly so as to avoid spicular
reflection.
Table continued on the next page.
Troubleshooting the
Readers