Lika SMK Series User manual
SMK -SML –SMH
MAN SMK-SML-SMH I_E 1.0 Pag.5www.lika.it
www.lika.biz
User manual
SMK, SML, SMH
Chapters
1 Safety summary
2 Identification
3 Installation
4 Output signals
5 Electrical connections
6 Dimensional drawing
7 Maintenance
8 Troubleshooting
Description
This manual describes products of the SMK, SML,
SMH series. The purpose of these sensors is to
measure linear or angular displacements on
industrial machines and automation systems. The
measurement system includes a magnetic tape and
a magnetic sensor. The tape has alternating
magnetic north/south poles are magnetized at a
certain distance called the pole pitch. As the sensor
is moved along the magnetic tape (or magnetic
ring), it detects the displacement and produces an
output signal equivalent to that of an incremental
encoder or a linear scale. The flexibility of the tape
allows it to be used for both linear and angular
applications.
The sensor has to be matched with the appropriated
magnetic tape (see chap. 2.1).
1 -Safety summary
We strongly recommend carefully reading this user
manual and following the installation guidelines:
•Sensor head should be installed as close as
possible to your control unit.
•Always use shielded cables and twisted if
possible.
•Avoid running the sensor cable near high
voltage power cables (e.g. drive cables).
•Install EMC filters on sensor power supply if
needed.
•Avoid mounting sensor head near capacitive or
inductive noise sources such as relays, motors,
and switching power supplies.
Connect according to the supplied pin-out.
2 -Identification
The sensor can be identified by the label's data
(ordering code, serial number). This information is
listed in the delivery document. All technical
features according to the ordering code are shown
on the catalogue.
2.1 Sensor and tape combinations
Sensor Magnetic tape
SMK MT50
SML MT32
SMH MT40
3 -Installation
Install the product according to the protection level
provided.
Protect the system against knocks, friction, solvents,
temperatures under -10°C (14°F) and over +70°C
(+158°F).
Be sure that the system is mounted where hard or
sharp objects (e.g. metal chips) do not come into
contact with the magnetic scale and the bottom of
the sensor head. If these conditions cannot be
avoided provide a wiper or pressurized air.
3.1 Mounting tolerances
Sensore
Gap
Sensor/Magnetic tape
(D)
SMK 4,0 mm
SML 2,0 mm
SMH 2,0 mm
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3.2 Mounting position with magnetic rings
Sensore
Gap
Sensor/Magnetic ring
(D)
SMK 4,0 mm
SML 2,0 mm
SMH 2,0 mm
For mounting tolerances refer to paragraph 3.1
4 -Output signals
With ordering code “N” the output signal "I" is not
available.
As the sensor is moved along the magnetic tape, it
detects the displacement and produces an output
signal equivalent to that of an incremental encoder
or a linear scale. The signal output is proportional
to the measuring speed and to the displacement of
the sensor. Resolution after quadrature (4 edge
reading) can be determined by the ordering code on
the sensor.
5 -Electrical connections
Output Colour
Ayellow
/A blue
Bgreen
/B orange
0white
/0 grey
GND black
+Vdc red
* see ordering code
"1" = +5Vdc ± 5%
"2" = +10Vdc +30Vdc
Note: All sensors have AquadB and inverted signals.
A = A signal
/A = inverted A signal (or complementary signal)
All our magnetic sensors can have A, /A, B, /B, 0, /0
output signals. We recommend always connecting
the inverted signals if the receiving device will
accept them. Otherwise the outputs should to be
insulated.
ATTENTION: connecting /A, /B, or /0 together, to
+Vdc or 0Vdc may cause permanent damage to the
sensor.
5.1 Specifications of the cable
Wires : 6 x 0.14mm2+ 2 x 0.24mm2
Screening : Copper
External Ø : Ø 5.2 mm ± 0.2 mm (Ø 0.2 in ± 0.01in)
Impedance : 6 x 145 Ω, 2 x 87 Ω
Notes:
•While connecting, power must be switched OFF;
•Check correct connections before switching ON;
•We recommend that the sensor head be
mounted as far as possible from any capacitive
or inductive noise source such as motors, relays
and switching devices;
•Avoid routing the sensor cable near high voltage
power cables in order to reduce influences of
electric noise;
•Only use shielded cables and wire with a cross
section between 0,14mm2and 0,5 mm2
•The shield of the cable and 0Vdc wire should be
connected to ground (GND);
SMK -SML –SMH
MAN SMK-SML-SMH I_E 1.0 Pag.7www.lika.it
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•Electric noise sources should be linked with
noise suppression filters;
•Total length of connection cable from sensor to
receiving device should not exceed 50 m (55').
6 -Dimensional drawing
7 -Maintenance
The magnetic measurement system doesn't need
any particular maintenance but as with all precision
devices it must be handled with care. From time to
time we recommend the following operations:
•Check the gap between sensor and magnetic
tape along the measuring length. Wear of the
machine may increase the tolerances.
•The surface of the magnetic tape should
occasionally be cleaned using a soft cloth to
remove dust, chips, moisture etc.
8 -Troubleshooting
The following list shows some typical errors that
occur during installation and operation of the
magnetic measurement system.
Problem:
The system doesn't work (no pulse output):
•The tape or sensor has been mounted incorrectly
(the active part of the tape doesn't face the
sensor's active side).
•A magnetic piece or tape is in between the
sensor and the tape. Only non-magnetic
materials are allowed between sensor and tape.
•The sensor touches the tape because tolerance
gap between sensor and tape are not observed.
Check sensor's active side if damaged.
•The sensor has been damaged by short circuit or
wrong connection.
Problem:
The measured values are inaccurate:
•The gap between sensor and tape is not
observed along the total measurement length.
•The connection cable runs near to high voltage
cable or shield is not connected correctly.
•The max. counting frequency of your receiving
device is too low.
•A section of the magnetic tape has been
damage mechanically or magnetically along the
measuring length
•The measuring error is caused by torsion of the
machine structure. Check parallelism and
symmetry of machine movement.
SMK -SML –SMH
MAN SMK-SML-SMH I_E 1.0 Pag.8www.lika.it
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Lika Electronic
Via S. Lorenzo, 25 –36010 Carrè (VI) -Italy
Tel. +39 0445 382814
Fax +39 0445 382797
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