1. PROBLEM - Contamination:
Since all glass scales operate on the
photoelectric measuring principle, any substantial distortion of the
light (i.e. Oil, Dirt, Chips) can cause the scale to misread.
SOLUTION-
Keep the scale clean. This is
achieved by keeping the sealing lips in good order and using common
sense when blowing chips or oil in the vicinity of the scale.
2. PROBLEM -
Misalignment:
When the lines on the scanning
reticle are not parallel to that of the glass, the light dark
fluctuations that are produced will not be symmetrical, causing an
unacceptable sinusoidal wave form.
SOLUTION-
Ensure that during the installation
of the system all of the mounting surfaces are flat and the scale moves
parallel to the travel of the machine. This alignment is generally
within +/- 0.004 inch. Also, worn or damaged springs in the
encoder can cause the misalignment in which case it is best to contact a
qualified service representative.
3. PROBLEM -
Light Source:
Many light sources in linear encoders
are incandescent lamps which may blow over a period of time just like a
light bulb in your house. Most newer encoders use a solid state
infra-red L.E.D. which allows for faster traverse speeds and longer
life. When the light source goes out, no signal is produced
causing the counter to remain at 0.0000 state even when the axis is
traveled. Most newer counters will flash or give an error message
when this occurs to notify the user there is a problem with the system.
SOLUTION-
A qualified service representative
should be contacted.
4. PROBLEM -
Wearing/Scratching of the glass or reticle:
When the glass or reticle are
scratched or worn, the light that passes through the scratched area is
disrupted just as with contamination. If the edge of the glass in
the scale is chipped or cracked the carriage will be shifted in this
area causing the signal to fluctuate.
SOLUTION-
A qualified service representative
should be contacted.
5. PROBLEM -
Crashing:
Sometimes a machine is over traveled
driving the encoder into the end cap. Repairs can range from
replacing a bent spring to replacing the entire scale depending on how
far the encoder was driven into the end cap.
SOLUTION-
Inspect the encoder for obvious
damage. If the encoder foot is broken, replace the encoder.
If the glass in the scale is broken, you will need to buy a new scale.
If there is no obvious damage contact your qualified service
representative. The repair is generally inexpensive.
6. PROBLEM -
Cabling:
Sometimes cables are pinched or torn
out of the encoder when the machine is traveled to extremes.
SOLUTION-
The solution is usually as simple as
replacing the cable. In rare instances the wires short together
and cause more problems that require a qualified service
representatives.
7. PROBLEM -
Display electronics:
Approximately 7% of all problems are
caused by the digital readout display. These problems range from
the simple power problems to bad control chips or EPROM's.
SOLUTIONS-
If you have eliminated the scales as
the cause of the problem, send in the box. Most readout repairs
are quick and inexpensive.
8. PROBLEM - Photocell:
When a photocell burns out or
becomes obstructed, the signal that is produced is faulty. This
will cause the scale to read improperly or not at all. The most
common symptom of photocell damage is the last digit on the display will
"flicker' when traveled.
SOLUTION-
Call a qualified service
representatives. The photocells in some encoders can be replaced
allowing for an inexpensive repair.
9. PROBLEM - Calibration:
Over time, encoders can fall out of
calibration due to deterioration of various components of dust buildup
in the encoder. This generally produces erratic readings or
non-repeatability.
SOLUTION-
If you have the knowledge and proper
equipment you can easily calibrate the encoder. Otherwise it is
best to call a qualified service representative to calibrate your system
to manufacturers specifications.
10. PROBLEM - User Error:
Many of today's high tech systems
have several programming options which can be inadvertently changed
or become confusing to the operator. These parameters can effect
the signal division, scaling or error correction in the readout.
SOLUTION-
A Tech Authority's qualified technicians
provide technical help over the phone, offering you fast access to
our knowledge to solve your problems.
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