LINEPULS & LINECOD catalogue 2016 in English

LINEPULS • LINECOD
Technical information
Mechanical and environmental information
The accuracy of a linear encoder system largely depends also on mechanical alignment,
thus the installers ability to maintain all mounting parameters within the tolerance values
specified in the technical documentation is vital for proper operation.
As stated, a linear encoder basically consists of a sensing head and a magnetic tape.
One of these encoder assembly component parts is mounted on a fixed support while the
other is secured to the moving structure of the application. In a customary installation, the
magnetic tape is applied to a fixed support, while the sensing head is fastened to the moving
unit. But sometimes, for instance in the measurement systems having a rigid track profile
such as SMIG and SMAG encoders, we could have the reading head fastened to a fixed support
while the magnetic tape is kept free to move.
In both cases, the relation between the reading head and the tape is critical and must be
preserved along the whole axis travel. Thus, mounting the two component parts parallel to
the axis of travel for all planes within specified tolerances will yield best results.
Great care is required when mounting a linear encoder because all the alignment dimensions
can seriously affect the proper operation of the measuring system.
The Figure below shows the critical features that must be assessed and taken into the
greatest consideration during installation.
Make sure that the gap D between the sensing head and the magnetic tape is always within
the tolerance values indicated in the specific documentation along the whole axis travel.
The same considerations concern the gap you have to comply with when installing the
sensing head and the external Reference magnet and/or the external limit switch magnets.
Check the parallelism and planarity
specifications for all the measuring
system component units:
sensing head, magnetic tape, reference
external magnet, limit switch
external magnets. Always comply
with the tolerances concerning roll,
tilt, yaw and lateral deviation. Alignment
specifications depend on
the characteristics of each specific
encoder model, so they are expressly
provided with installation literature.
Install the measurement system
providing protection means against
waste, especially swarf as turnings,
chips or filings; should this not be
possible, please make sure that
adequate cleaning measures (as
for instance brushes, scrapers, jets
of compressed air, etc.) are in place
in order to prevent the reading
head and the magnetic tape from
jamming. Optional rubber cleaning
wipers can be supplied in specific
models (see on page 15).
The magnetic tape must be mounted evenly on the application surface ensuring that it
is perfectly levelled and free of bumps. The adhesion of the tape to the bonding surface
depends on a variety of factors such as the cleaning, the temperature at application, the
roughness of the materials and the smoothness of the bonding surface. To obtain optimum
and safe adhesion, the bonding surfaces must be well unified, clean and dry. The ideal application
temperature range is +21°C to +38°C (+70°F to +100°F). Do not wind the tape with
the magnetized side facing outwards. Do not twist or bend the magnetic tape.
For the recommended tape length in relation to the travel to be measured please see the
section “Tape dimensions“ on page 12.
Both the magnetic sensor and the tape are sensitive to magnetic fields and may be damaged
even permanently if exposed to a powerful magnetic field generated by magnetic tools
or linear motors. Please use precautionary procedures during installation in order to avoid
performance degradation or loss of functionality. Always keep the measuring system a safe
distance from devices producing strong magnetic fields.
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