Lika Sma5-ga series User manual

User's guide
SMA5 +
MTA5
•SMA5 absolute linear encoder
•MTA5 tape, 5 mm pitch, unaffected by dust and liquids
•Max  measuring length 5,100 mm / 200 787”
•Resolution from 100 µm down to 5 µm
•SSI interface
Suitable for the following models:
•SMA5 -GA- 
Table of Contents
Preliminary information 5
1 - Safety summary 6
2 - Identification 7
3 – Mounting instructions 8
4 - Electrical connections 11
5 - SSI interface 14
6 – Error and fault diagnostics 17
7 - Maintenance 18
8 - Troubleshooting 19
Lika Electronic    •    Tel  +39 0445 806600    •    info@lika biz    •    www lika biz
Smart encoders & actuators

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part without prior written approval o Lika Electronic s.r.l. Translation, reproduction and total or partial modi ication (photostat copies,

ilm and micro ilm included and any other means) are orbidden without written authorisation o Lika Electronic s.r.l.

The in ormation herein is subject to change without notice and should not be construed as a commitment by Lika Electronic s.r.l. Lika

Electronic s.r.l. reserves the right to make all modi ications at any moments and without orewarning.

This manual is periodically reviewed and revised. As required we suggest checking i a new or updated edition o this document is

available at Lika Electronic s.r.l.'s website. Lika Electronic s.r.l. assumes no responsibility or any errors or omissions in this document.

Critical evaluation o this manual by the user is welcomed. Your comments assist us in preparation o uture documentation, in order

to make it as clear and complete as possible. Please send an e-mail to the ollowing address in [email protected] or submitting your

comments, suggestions and criticisms.

General contents
User's guide............................................................................................................................................................................................1
General contents..................................................................................................................................................................................3
Typographic and iconographic conventions........................................................................................................................4
Preliminary information..................................................................................................................................................................5
- Safety summary 6
1 Sa ety..........................................................................................................................................................................................6
2 Electrical sa ety.......................................................................................................................................................................6
3 Mechanical sa ety..................................................................................................................................................................7
- Identification 7
– Mounting instructions 8
1 Overall dimensions................................................................................................................................................................8
2 Magnetic tape.........................................................................................................................................................................8
3 Mounting the sensor............................................................................................................................................................9
- Electrical connections 11
1 M12 8-pin connector speci ications...........................................................................................................................11
2 M8 cable speci ications....................................................................................................................................................11
3 Ground connection............................................................................................................................................................12
4 Zero setting............................................................................................................................................................................12
5 Counting direction..............................................................................................................................................................12
6 Features summary...............................................................................................................................................................13
- SSI interface 14
1 SSI (Synchronous Serial Inter ace)...............................................................................................................................14
2 LSB Right Aligned protocol.............................................................................................................................................15
3 Recommended transmission rates...............................................................................................................................16
– Error and fault diagnostics 17
1 Diagnostic LED......................................................................................................................................................................17
- Maintenance 18
- Troubleshooting 19

Typographic and iconographic conventions

In this guide, to make it easier to understand and read the text the ollowing typographic and

iconographic conventions are used:

•parameters and objects both o the device and the inter ace are coloured in GREEN;

•alarms are coloured in RED;

•states are coloured in FUCSIA.

When scrolling through the text some icons can be ound on the side o the page: they are expressly

designed to highlight the parts o the text which are o great interest and signi icance or the user.

Sometimes they are used to warn against dangers or potential sources o danger arising rom the use o

the device. You are advised to ollow strictly the instructions given in this guide in order to guarantee

the sa ety o the user and ensure the per ormance o the device. In this guide the ollowing symbols are

used:

This icon, ollowed by the word WARNING, is meant to highlight the parts o the

text where in ormation o great signi icance or the user can be ound: user must

pay the greatest attention to them! Instructions must be ollowed strictly in order

to guarantee the sa ety o the user and a correct use o the device. Failure to heed

a warning or comply with instructions could lead to personal injury and/or damage

to the unit or other equipment.

This icon, ollowed by the word NOTE, is meant to highlight the parts o the text

where important notes need ul or a correct and reliable use o the device can be

ound. User must pay attention to them! Failure to comply with instructions could

cause the equipment to be set wrongly: hence a aulty and improper working o

the device could be the consequence.

This icon is meant to highlight the parts o the text where suggestions use ul or

making it easier to set the device and optimize per ormance and reliability can be

ound. Sometimes this symbol is ollowed by the word EXAMPLE when instructions

or setting parameters are accompanied by examples to clari y the explanation.

Preliminary information

This guide is designed to provide the most complete and exhaustive in ormation the operator needs to

correctly and sa ely install and operate the SMA5 series absolute linear encoder.

SMA5 is designed to measure displacements in industrial machines and automation systems. The

measurement system includes a magnetic tape and a magnetic sensor with conversion electronics. The

scale is magnetized with a coded sequence o North-South poles generating an absolute pattern. As the

encoder moves along the magnetic scale, the sensor detects the displacement and yields the absolute

position in ormation through the SSI inter ace (order code SMA5-GA-...).

It is mandatory to pair the sensor with the MTA5 type magnetic tape.

To make it easier to read and understand the text, this guide can be divided into two main sections.

In the irst section some general in ormation concerning the sa ety, the mechanical installation and the

electrical connection as well as tips or setting up and running properly and e iciently the unit are

provided.

In the second section, entitled SSI interface, both general and speci ic in ormation is given on the SSI

inter ace.

SMA5

1 - Safety summary

1 1 Safety

•Always adhere to the pro essional sa ety and accident prevention

regulations applicable to your country during device installation and

operation;

•installation and maintenance operations have to be carried out by

quali ied personnel only, with power supply disconnected and stationary

mechanical parts;

•device must be used only or the purpose appropriate to its design: use or

purposes other than those or which it has been designed could result in

serious personal and/or the environment damage;

•high current, voltage and moving mechanical parts can cause serious or

atal injury;

•warning ! Do not use in explosive or lammable areas;

•ailure to comply with these precautions or with speci ic warnings

elsewhere in this manual violates sa ety standards o design, manu acture,

and intended use o the equipment;

•Lika Electronic assumes no liability or the customer's ailure to comply

with these requirements.

1 2 Electrical safety

•Turn OFF power supply be ore connecting the device;

•connect the unit according to the explanation in the ”4 - Electrical

connections” section on page 11;

•the wires o unused signals must be cut at di erent lengths and insulated

singularly;

•connect Zero setting and Counting direction inputs to 0Vdc, i not used;

- to zero set the encoder, connect the Zero setting input to +Vdc or 100

µs at least, then disconnect +Vdc; normally voltage must be at 0Vdc; zero

setting must be per ormed a ter Counting direction; we suggest

per orming the zero setting when the encoder is in stop;

- Counting direction (see the “3 – Mounting instructions” section):

increasing count = connect to 0Vdc; decreasing count = connect to

+Vdc;

•in compliance with 2014/30/UE norm on electromagnetic

compatibility, ollowing precautions must be taken:

- be ore handling and installing the equipment, discharge

electrical charge rom your body and tools which may come in touch

with the device;

- power supply must be stabilized without noise; install EMC ilters on

device power supply i needed; T or P type LC ilters are o ten adequate;

- always use shielded cables (twisted pair cables whenever possible);

- avoid cables runs longer than necessary;

- avoid running the signal cable near high voltage power cables (e.g. drive

cables);

- install the device as close as possible to the electronic control unit;

- mount the device as ar as possible rom any capacitive or inductive

noise source; shield the device rom noise source i needed;

MAN SMA5 E 1.8.odt 1 - Sa ety summary 6 o 20

SMA5

- mount the device as ar as possible rom the inverter (i installed in the

machine); shield the device i needed;

- to guarantee a correct working o the device, avoid using strong magnets

on or near by the unit;

- minimize noise by connecting the cable shield and/or the connector

housing and/or the sensor to ground. Make sure that ground is not

a ected by noise. The connection point to ground can be situated both

on the device side and on user’s side. The best solution to minimize the

inter erence must be carried out by the user.

1 3 Mechanical safety

•Install the device ollowing strictly the in ormation in the “3 – Mounting

instructions” section on page 8;

•mechanical installation has to be carried out with stationary mechanical

parts;

•do not disassemble the unit;

•do not tool the unit;

•delicate electronic equipment: handle with care; do not subject the device

to knocks or shocks;

•protect the unit against acid solutions or chemicals that may damage it;

•respect the environmental characteristics o the product;

•we suggest installing the unit providing protection means against waste,

especially swar as turnings, chips, or ilings; should this not be possible,

please make sure that adequate cleaning measures (as or instance

brushes, scrapers, jets o compressed air, etc.) are in place in order to

prevent the sensor and the magnetic scale rom jamming.

CAUTION

Keep magnets away rom the tape, it could be damaged by strong magnetic

ields.

2 - Identification

Device can be identi ied through the order code and the serial number printed

on the label applied to its body. In ormation is listed in the delivery document

too. Please always quote the order code and the serial number when reaching

Lika Electronic or purchasing spare parts or needing assistance. For any

in ormation on the technical characteristics o the product re er to the

technical datasheet.

Warning: devices having order code ending with "/Sxxx" may have

mechanical and electrical characteristics di erent rom standard

and be supplied with additional documentation or special

connections (Technical In o).

MAN SMA5 E 1.8.odt 2 - Identi ication 7 o 20

SMA5

3 – Mounting instructions

WARNING

Installation has to be carried out by quali ied personnel only, with power supply

disconnected and mechanical parts compulsorily in stop.

3 1 Overall dimensions

3 2 Magnetic tape

The sensor has to be paired with the MTA5 type magnetic scale only. For

detailed in ormation on the MTA5 type scale and how to mount it re er to the

speci ic technical documentation.

Install the unit providing protection means against waste, especially swar as

turnings, chips, or ilings; should this not be possible, please make sure that

adequate cleaning measures (as or instance brushes, scrapers, jets o

compressed air, etc.) are in place in order to prevent the sensor and the

magnetic scale rom jamming.

Make sure the mechanical installation meets the system's requirements o

distance, planarity and parallelism between the sensor and the scale indicated in

Figure 2 all along the whole measuring length.

MTA5 magnetic scale can be provided with a cover strip to protect its magnetic

sur ace (see the order code).

The Figure 1 shows how the sensor and the scale must be installed; the arrow

indicates the standard counting direction (increasing count, see on page 12).

WARNING

The system cannot work i mounted otherwise than illustrated in Figure 1.

MAN SMA5 E 1.8.odt 3 – Mounting instructions 8 o 20

SMA5

3 3 Mounting the sensor

Figure 1

Make sure the mechanical installation complies with the system requirements

concerning distance, planarity and parallelism between the sensor and the scale.

Avoid contact between the parts. Sensor is ixed by means o two M5 25 mm

min long cylinder head screws inserted in the provided holes. Recommended

minimum bend radius o the cable: R  42 mm.

Please note that the MTA5 magnetic scale can be provided with a cover strip to

protect its magnetic sur ace (see the order code). There ore the distance

between the sensor and the magnetic scale is di erent whether the cover strip

is applied.

The allowed gap D (see Figure 2) between the sensor and the scale must

be in the range indicated in the following table:

Gap sensor / MTA5 magnetic scale (D)

without cover strip with cover strip

0.1 – 1.0 mm / 0.004” - 0.04” 0.1 – 0.6 mm / 0.004” - 0.024”

WARNING

Make sure the mechanical installation complies with the system requirements

concerning distance, planarity and parallelism between the sensor and the scale

as shown in Figure 2 all along the whole measuring length.

MAN SMA5 E 1.8.odt 3 – Mounting instructions 9 o 20

SMA5

Figure 2

WARNING

A ter having installed the sensor on the magnetic scale a zero setting operation

is compulsorily required. The zero setting operation is urther required every

time either the sensor or the scale is replaced. For urther in ormation re er to

page 12.

CAUTION

Keep magnets away rom the tape, it could be damaged by strong magnetic

ields.

MAN SMA5 E 1.8.odt 3 – Mounting instructions 10 o 20

SMA5

4 - Electrical connections

WARNING

Electrical connection has to be carried out by quali ied personnel only, with

power supply disconnected and mechanical parts compulsorily in stop.

WARNING

I wires o unused signals come in contact, irreparable damage could be caused

to the device. Please insulate them singularly.

Connections

Function M12 8-pin M8 cable

0Vdc 1 Black

+10Vdc +30Vdc 2 Red

CLOCK IN + 3 Yellow

CLOCK IN - 4 Blue

DATA OUT + 5 Green

DATA OUT - 6 Orange

Zero setting 7 White

Counting direction 8 Grey

Shielding Case Shield

4 1 M12 8-pin connector specifications

M12 8-pin connector

male, rontal side

A coding

4 2 M8 cable specifications

Model : LIKA HI-FLEX sensor cable type M8

Wires : 2 x 0.22 mm2 + 6 x 0.14 mm2 (24/26 AWG)

Jacket : Matt Polyurethane (TPU) halogen ree, oil, hydrolysis,

abrasion resistant

Shield : tinned copper braid, coverage  85%

Outer diameter : 5.3 mm ÷ 5.6 mm (0.209” ÷ 0.220”)

Min. bend radius : Ø x 7.5

Work temperature : -40°C +90°C (-40°F +194°F) – dynamic installation

-50°C +90°C (-58°F +194°F) – ixed installation

Conductor resistance :  90 /km /  148 /km

MAN SMA5 E 1.8.odt 4 - Electrical connections 11 o 20

SMA5

4 3 Ground connection

Minimize noise by connecting the shield and/or the connector housing and/or

the sensor to ground. Make sure that ground is not a ected by noise. The

connection point to ground can be situated both on the device side and on

user’s side. The best solution to minimize the inter erence must be carried out by

the user.

4 4 Zero setting

The output value can be set to zero (reset) by means o an external signal sent

by a PLC or other device. The internal microprocessor uses this signal to zero set

the position in ormation. Thus the position in ormation will be “0” in the point

where the operation is per ormed. Connect the Zero setting input to 0Vdc i not

used. To zero set the value, connect the input to +Vdc or 100 µs at least, then

disconnect +Vdc. Normally voltage must be at 0Vdc. The reset must be

per ormed when the sensor is in stop. You must set the Counting direction irst

and then zero set the encoder position.

NOTE

Please note that, a ter setting the zero point, the positive counting will be rom

0 towards the max. value (see on page 15); i you move the axis be ore the 0

point, the detected value will decrement starting rom the max. number o

in ormation – 1 down. For example:

... 65533 65534 65535 0 1 2 3 ...

4 5 Counting direction

The standard counting direction is to be intended with sensor moving as

indicated by the arrow in Figure 1. This input allows to reverse the counting

direction. In other words, it allows the count up when the sensor moves in the

reverse o the standard direction, i.e. in the opposite direction to the one shown

by the arrow in Figure 1. Connect the input to 0Vdc i not used. When the

Counting direction input is connected to 0Vdc, the position in ormation

increases when the sensor moves according to the arrow in Figure 1. When the

Counting direction input is connected to +Vdc, the position in ormation

increases when the sensor moves in reverse o the standard direction, i.e. in the

opposite direction to the one shown by the arrow in Figure 1.

WARNING

A zero setting operation is required a ter setting the counting direction.

MAN SMA5 E 1.8.odt 4 - Electrical connections 12 o 20

SMA5

4 6 Features summary

Order code Resolution mm

SMA5-GA-100- 0.1

SMA5-GA-50- 0.05

SMA5-GA-10- 0.01

SMA5-GA-5- 0.005

Max length of the scale

(max measuring length)

5,100 mm / 200.787”

(5,035 mm / 198.23”)

Pole pitch dimension 5 mm

Max information

(max value) 20 bits (1,048,575)

MAN SMA5 E 1.8.odt 4 - Electrical connections 13 o 20

SMA5

5 - SSI interface

Order code: SMA5-GA-…

5 1 SSI (Synchronous Serial Interface)

SSI (the acronym or Synchronous Serial

Interface) is a synchronous point-to-point serial

inter ace engineered or unidirectional data

transmission between one Master and one Slave.

Developed in the irst eighties, it is based on the RS-

422 serial standard. Its most peculiar eature is that data transmission is

achieved by synchronizing both the Master and the Slave devices to a common

clock signal generated by the controller; in this way the output in ormation is

clocked out at each controller's request. Furthermore only two pairs o twisted

wires are used or data and clock signals, thus a six-wire cable is required.

The main advantages in comparison with parallel or asynchronous data

transmissions are:

•less conductors are required or transmission;

•less electronic components;

•possibility o insulting the circuits galvanically by means o

optocouplers;

•high data transmission requency;

•hardware inter ace independent rom the resolution o the absolute

encoder.

Furthermore the di erential transmission increases the noise immunity and

decreases the noise emissions. It allows multiplexing rom several encoders, thus

process controls are more reliable with simpli ied line design and easier data

management.

Data transmission is carried out as ollows.

A ter the logic level o the clock signal changes rom high to low ( irst alling

edge 1) and then changes rom low to high (the ollowing rising edge 2) the

transmission o data in ormation begins starting rom the MSB.

At each change o the clock signal and at each subsequent rising edge (2) one

bit is clocked out at a time, up to LSB, so completing the data word

MAN SMA5 E 1.8.odt 5 - SSI inter ace 14 o 20

SMA5

transmission. The cycle ends at the last rising edge o the clock signal (3). This

means that up to n + 1 rising edges o the clock signals are required or each

data word transmission (where n is the bit resolution); or instance, a 13-bit

encoder needs 14 clock edges. I the number o clocks is greater than the

number o bits o the data word, then the system will send a zero (low logic

level signal) at each additional clock, zeros will either lead (LSB ALIGNED

protocol) or ollow (MSB ALIGNED protocol) or lead and/or ollow (TREE FORMAT

protocol) the data word. SMA5 always requires 25 clocks. A ter the period Tm

mono lop time, having a typical duration o 12 µsec, calculated rom the end o

the clock signal transmission, the absolute position value is stored and the

encoder is then ready or the next transmission and there ore the data signal is

switched high.

The clock signal has a typical logic level o 5V, the same as the output signal

which has customarily a logic level o 5V in compliance with RS-422 standard.

The output code can be either Binary or Gray (see the order code).

5 2 LSB Right Aligned protocol

“LSB Right Aligned” protocol allows to right align the bits, beginning rom MSB

(most signi icant bit) to LSB (least signi icant bit); LSB is then sent at the last

clock cycle. Transmitted bits are always 25, the sensor always requires 25 clocks.

Unused bits are set to 0 (zero) and lead the data word:

Model Resolution Length of the word

Max number of

information

(max value)

SMA5-GA-100- 0.1 mm 25 bits 16 bits (65.535)

SMA5-GA-50-… 0.05 mm 25 bits 17 bits (131.071)

SMA5-GA-10-… 0.01 mm 25 bits 19 bits (524.287)

SMA5-GA-5-… 0.005 mm 25 bits 20 bits (1.048.575)

The output code o the sensor is GRAY.

The length o each in ormation is equal to the resolution (0.1 mm … 0.005 mm).

Position in ormation structure:

SMA5-GA-100- bits 25 … 16 15 0

SMA5-GA-50- bits 25 … 17 16 0

SMA5-GA-10- bits 25 … 19 18 0

SMA5-GA-5- bits 25 … 20 19 0

value 00 … 00 MSB … LSB

MAN SMA5 E 1.8.odt 5 - SSI inter ace 15 o 20

SMA5

WARNING

The position value issued by the sensor is expressed in pulses; to convert the

pulses into a metric measuring unit you must multiply the number o detected

pulses by the resolution.

EXAMPLE

SMA5-GA-5-…

resolution = 5 µm = 0.005 mm

detected pulses = 123

position value = 123 * 5 = 615 µm = 0.615 mm

5 3 Recommended transmission rates

The SSI inter ace has a requency o data transmission ranging between 100 kHz

and 1.5 MHz.

The CLOCK signal and DATA signal comply with the “EIA standard RS-422”.

The clock requency (baud rate) depends on the length o the cable and must

comply with the technical in ormation reported in the ollowing table:

Cable length Baud rate

< 50 m < 400 kHz

< 100 m < 300 kHz

< 200 m < 200 kHz

< 400 m < 100 kHz

The time interval between two Clock sequence transmissions must be at least 30

µs ( Tp > 30 µs).

MAN SMA5 E 1.8.odt 5 - SSI inter ace 16 o 20

SMA5

6 – Error and fault diagnostics

In case o wrong alignment between the sensor and the magnetic scale, at

power on or during operation the ollowing errors may occur:

the LED lights up when switching on the system: there is a wrong

alignment; position value 0 (zero) is transmitted until valid data is detected;

please install the sensor properly; as soon as the sensor is aligned correctly

the LED switches o ;

the LED lights up during operation: the last valid position is “ rozen” (kept in

memory) until the next valid position is detected on the scale.

6 1 Diagnostic LED

When the LED lights up, it indicates that an error is active, such as or instance

an incorrect alignment between the sensor and the scale:

the gap between the sensor and the scale is out o tolerance (see Figure 2)

the sensor is not installed properly

the sensor or the scale are installed upside down

the sensor is installed in the opposite direction to the one shown in Figure 1

the sensor is travelling too ast

the power supply is not as required

NOTE

When the LED is o , this means that the sensor is working properly and the

absolute position is output correctly.

For urther in ormation re er also to the “8 - Troubleshooting” section on page

19.

MAN SMA5 E 1.8.odt 6 – Error and ault diagnostics 17 o 20

SMA5

7 - Maintenance

The magnetic measurement system does not need any particular maintenance;

anyway it has to be handled with the utmost care as any delicate electronic

equipment. From time to time we recommend the ollowing operations:

periodically check the soundness o the structure and make sure that there

are no loose screws; tighten them i necessary;

check the gap between the sensor and the magnetic scale all along the

whole measuring length. Wear o the machine may increase the tolerances;

the sur ace o the magnetic scale has to be regularly cleaned using a so t

and clean cloth to remove dust, chips, moisture etc.

MAN SMA5 E 1.8.odt 7 - Maintenance 18 o 20

SMA5
8 - Troubleshooting
The  ollowing list shows some typical  aults that may occur during installation
and operation o  the magnetic measurement system.
Fault
The system does not work (no pulse output)
The scale and/or the sensor are not installed properly (the active sur ace o 
the  scale  does  not   match  the  sensitive  part  o   the  sensor). For  correct
installation please re er to the “3 – Mounting instructions” section on page
8. The diagnostic LED is lit.
A magnetic part or a protection sur ace is interposed between the sensor
and the scale. Only non-magnetic materials are allowed between the sensor
and the scale. The diagnostic LED is lit.
Installation does not comply with the tolerance gap between the sensor and
the scale indicated in this guide; the sensor hits the sur ace o  the scale or is
too  ar  rom it. Check whether the sensor sensitive part is damaged.
The sensor has been damaged by short circuit or wrong connection.
Fault
The measured values are either inaccurate or not provided in the whole length
The gap between the sensor and the scale is not respected all along the
whole measuring length. See the “3 – Mounting instructions” section on
page 8.
The sensor is not installed properly on the scale. See the “3 – Mounting
instructions” section on page 8.
The connection cable runs near high voltage cables or the shield is not
connected properly. Check the earthing point.
The  requency  o  the  Master  clock  is  set too  high  or  too  low  and  the
transmission cannot be synchronized correctly. See the “5 - SSI inter ace”
section on page 14.
A   section   o   the   magnetic   scale   has   been   damaged   mechanically   or
magnetically along the measuring length.
The measuring error is caused by a torsion in the machine structure. Check
parallelism and symmetry in the movement o  the machine.
For  urther in ormation re er also to the “6 – Error and  ault diagnostics” section
on page 17.
MAN SMA5 E 1.8.odt 8 - Troubleshooting 19 o  20

Document release Release date Description HW SW Interface
1.0 04.11.2004 First issue
1.1 02.12.2004 User's guide updated
1.2 25.01.2005 User's guide updated
1.3 12.10.2010 “5 - SSI inter ace” section updated
1.4 04.09.2013 User's guide updated, “5 - SSI inter ace” section 
updated
1.5 06.08.2014 General review, “3 – Mounting instructions” section
updated
1.6 13.11.2015 M12 8-pin connector added, installation with cover
strip
1.7 21.04.2016 General review
1.8 31.01.2020 SSI in ormation updated, general review
Lika Electronic
Via S. Lorenzo, 25 • 36010 Carrè (VI) • Italy
Tel. +39 0445 806600
Fax +39 0445 806699
in [email protected] • www.lika.biz