SNC 021
S-DIAS Safety
Incremental Encoder
Date of creation: 14.11.2017
Version date: 02.12.2019
Article number: 20-896-021-E
Publisher: SIGMATEK GmbH & Co KG
A-5112 Lamprechtshausen
Tel.: +43/6274/4321
Fax : +43/6274/4321-18
Email: office@sigmatek.at
WWW.SIGMATEK-AUTOMATION.COM
Copyright © 2017
SIGMATEK GmbH & Co KG
Translation from German
All rights reserved. No part of this work may be reproduced, edited using an electronic system, duplicated or
distributed in any form (print, photocopy, microfilm or in any other process) without the express permission.
We reserve the right to make changes in the content without notice. The SIGMATEK GmbH & Co KG is not responsible
for technical or printing errors in the handbook and assumes no responsibility for damages that occur through use
of this handbook.
S-DIAS SAFETY SNC INCREMENTAL ENCODER SNC 021
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S-DIAS Safety SNC Incremental Encoder SNC 021
The S-DIAS Safety SNC incremental encoder module SNC 021 provides
the values of two incremental encoders, the Safety CPU as well as the nonSafe CPU (standard PLC).
The two-channel safety function "monitors" the increments in the
incremental encoder interfaces and processes the so-called Safety core in
two micro controllers with cross-communication.
The incremental encoder function is monitored through a 2-channel
analysis of the encoder signals, with 2-channel error detection of each data
line, as well as via the measurement of the encoder supply voltages and
currents.
Speed, position, direction and acceleration are monitored via the Safe
application in the Safety CPU.
The module detects various error types, such as a cable break, cross-circuit
and inverted input signals.
The safety functions of the module meet
• for two-channel application
the requirements for SIL 3 or SIL CL 3 in accordance with EN / IEC 62061 and PL e,
Cat. 4 in accordance with EN ISO 13849-1/-2
as well as
• for one-channel application,
the requirements for SIL 2 or SIL CL 2 in accordance with EN / IEC 62061 and PL d,
Cat. 2 in accordance with EN ISO 13849-1/-2.
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Contents
1 Basic Safety Guidelines .......................................................... 4
1.1 General Safety Information .......................................................... 4
1.2 Further Safety Guidelines ............................................................ 5
1.3 General Requirements ................................................................. 6
2 Conformity with EU Guidelines ............................................ 11
2.1 Functional Safety Standards ..................................................... 11
2.2 EU Conformity Declaration ........................................................ 11
2.3 Safety-Relevant Parameters ...................................................... 12
2.4 Compatibility ............................................................................... 13
3 Technical Data ....................................................................... 14
3.1 I-encoder Specifications ............................................................ 14
3.2 Electrical Requirements ............................................................. 14
3.3 Miscellaneous ............................................................................. 16
3.4 Environmental Conditions ......................................................... 16
4 Mechanical Dimensions ........................................................ 17
5 Connector Layout .................................................................. 18
5.1 Status LEDs ................................................................................. 19
5.2 Applicable Connectors ............................................................... 20
5.3 Label Field ................................................................................... 21
6 Wiring ..................................................................................... 22
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6.1 Wiring Example ........................................................................... 22
6.2 Note .............................................................................................. 23
7 RS422 Interface ..................................................................... 23
8 Mounting ................................................................................ 24
9 Disposal ................................................................................. 25
10 Encoder Configuration ......................................................... 26
11 Installing the Encoder ........................................................... 28
12 Important Notes for Two-channel Application .................... 29
13 Supported Cycle Times ........................................................ 31
13.1 Cycle Times below 1 ms (in µs) ................................................. 31
13.2 Cycle Times equal to or higher than 1 ms (in ms) ................... 31
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1 Basic Safety Guidelines
1.1 General Safety Information
Non-compliance with the Safety guidelines can result in danger to personnel, which could
then lead to serious injury or in worst cases, death. In less serious cases, systems and
equipment can be damaged.
The following symbols identify the individual risks as well as the degree of seriousness; their
respective meanings are briefly explained below. You should therefore familiarize yourself
with the Safety symbols and their meanings to prevent dangers and risks.
DANGER
DANGER
Identifies an immediate danger with high risk, which
can lead to immediate death or serious injury if not
avoided.
Indique un danger direct à haut risque d’un décès
immédiat ou des blessures graves si les consignes de
sécurité ne sont pas respectées.
WARNING
WARNING
Identifies a possible danger with a mid-level risk, which
can lead to death or (serious) injury if not avoided.
Indique un danger possible d’un risque moyen de
décès ou de (graves) blessures si les consignes de
sécurité ne sont pas respectées.
CAUTION
CAUTION
Identifies a low risk danger, which can lead to injury or
property damage if not avoided.
Indique un danger avec un niveau de risque faible des
blessures légères ou des dommages matériels si les
consignes de sécurité ne sont pas respectées.
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1.2 Further Safety Guidelines
Warning, dangerous electrical voltage
Avertissement d’une tension électrique dangereuse
Hot surface warning
Avertissement d’une surface chaude
Danger for ESD-sensitive components
This symbol identifies important or additional
information regarding the operation of the safety
modules.
Ce symbole indique des informations importantes ou
supplémentaires concernant le fonctionnement des
modules de sécurité particuliers.
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1.3 General Requirements
Technical
Documentation
This technical documentation is a component of this product.
• This document must be accessible near the machine,
since it contains important instructions.
• The technical documentation should be included in the
sale, rental or transfer of the product.
Documentation technique
Cette documentation technique fait partie intégrale du produit.
• Gardez la toujours à portée de main et à la proximité de
la machine, car elle contient des informations
importantes.
• Distribuez la documentation technique aux secteurs de
la vente et/ou de la location du produit.
S-DIAS SAFETY SNC INCREMENTAL ENCODER SNC 021
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Acceptance of Safety
Guidelines
Before handling the product to which this documentation
belongs, the operating instructions and safety guidelines must be
read. SIGMATEK GmbH & Co KG accepts no liability for
damages resulting from non-compliance with the Safety
guidelines or applicable regulations.
Acceptance of the Safety guidelines and the explanations in this
document, as well as the Safety System Handbook (see
homepage1) are a basic requirement for proper use. Therefore,
read this operating manual thoroughly and familiarize yourself
with each of them in detail.
More information on standards and regulations etc. can be found
in the system handbook.
Prendre connaissance de consignes de sécurité
Avant toute manipulation on doit impérativement prendre
connaissance de consignes de sécurité et du mode d’emploi.
SIGMATEK GmbH & Co KG n'assume aucune responsabilité
pour les dommages causés par le non-respect des consignes de
sécurité ou du mode d’emploi respectif.
La connaissance de consignes de sécurité et le contenu de cette
documentation ainsi que le mode d’emploi du système de
sécurité constitue une condition préalable à l'utilisation prévue.
Lisez ce mode d’emploi et assurez-vous de le comprendre
jusqu’aux détails.
Pour plus d'informations sur les normes et les lignes directrices,
etc., reportez-vous au mode d’emploi
1
Using the search function with the keyword “Safety System Handbook”
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Qualified Personnel
Installation, assembly, programming and initial start-up,
operation, maintenance and decommissioning of control and
automation technology products in general, as well as safe
products in particular, can only be performed by qualified
personnel.
Qualified personnel in this context are people, who have
completed training or have trained under supervision of qualified
personnel and have been authorized to operate and maintain
equipment of functional safety, systems and facilities in
compliance with the strict guidelines and standards of Safety
technology.
Personnel qualifié
Installation, montage, programmation, mise en service,
l'exploitation, l'entretien et mise hors service de produits de
commande et d'automatisation en général, et de produits liés à
la sécurité, en particulier, ne peut être effectuée que par le
personnel qualifié.
On entend sous terme personnel qualifié les personnes ayant
acquis une formation professionnelle dispensé par un spécialiste
sur l’utilisation et surveillance des composants et des systèmes
de sécurité, ceci conformément aux lignes directrices et les
normes en vigueur.
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Designated Use
The Safety modules are designed for use in applications with a
requirement of functional safety and meet the required conditions
for Safe operation with the parameters specified in section 2.
For your own safety and the safety of others, use Safety modules
for their designated purpose only. Correct EMC installation as
well as proper transport and storage are also included under
designated use.
Non-designated use consists of:
• any change made to the Safety modules of any kind.
• the use of damaged Safety modules.
• the use of the Safety module inconsistent with the
instructions described in this handbook.
• The use of the safety module inconsistent with the
technical data described in this handbook.
Les modules de sécurité sont conçus pour une utilisation dans
les applications sollicitant un niveau de sécurité et répondent à
toutes les conditions nécessaires pour un fonctionnement sûr
conformément au niveau de performance e (PL e) selon la norme
EN ISO 13849-1/-2 et SIL 3 ou SIL CL 3 de la norme EN 62061.
Utilisation prévue
Utilisez le module de sécurité conformément à son mode
d’emploi pour votre propre sécurité et celle d'autres personnes.
L'utilisation conforme comprend également une installation
conforme CEM ainsi que le transport et le stockage conforme.
L'utilisation abusive comprend entre autres:
• Les modifications quelconques apportées aux modules
de sécurité.
• Utilisation de modules de sécurité endommagés.
• Utilisation de modules de sécurité en dehors du cadre
décrit dans ce mode d’emploi.
• Utilisation de modules de sécurité en dehors des
spécifications décrites dans ce mode d’emploi.
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Operator Due Diligence
The operator must ensure that
• the Safety modules are to be used for their designated
purpose only.
• the Safety modules are to be operated in error-free, fully
functional condition only.
• only sufficiently qualified and authorized personnel
operate the Safety modules.
This documentation is complete and in readable condition and
available at the site of operation.
Obligation de diligence
L’utilisateur doit s'assurer que
• les modules de sécurité ne sont utilisés que selon les
spécifications.
• uniquement les modules de sécurité en parfait état de
fonctionnement peuvent être utilisés.
• seulement le personnel qualifié et autorisé puisse
manipuler les modules de sécurité.
la documentation dans son intégralité et dans un état lisible est
mise à disposition à l’endroit où les modules de sécurité sont
utilisés.
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2 Conformity with EU Guidelines
2.1 Functional Safety Standards
- EN / IEC 62061:2005/A2:2015
- EN ISO 13849-1:2015
- EN ISO 13849-2:2012
2.2 EU Conformity Declaration
CE Declaration of Conformity
The SNC 021 complies with European norms for programmable logic
controls.
• 2006/42/EG “Directive of the European Parliament and of the
Council of 17 May 2006 on Machinery and Change to the Directive
95/16/EC” (machine guideline)
• 2014/30/EU “Electromagnetic Compatibility” (EMC guideline)
• 2011/65/EU Restricted use of certain hazardous substances in
electrical and electronic equipment (RoHS Guideline)
The EU Conformity Declarations are provided on the SIGMATEK website.
Using the search function with the keyword “EU Declaration of Conformity”.
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2.3 Safety-Relevant Parameters
Input Module
2-channel application
Safety parameters for two
connected incremental encoders,
which monitor one another in the SNC
021
1-channel application
Safety parameters for one
connected incremental encoder, which
is monitored
in the SNC 021
SNC 021
including CPU modules
SCP 011/SCP 111
PFHD = 3.51E-09 (1/h)
MTTFD = 580 years
DC = 99.00 %
SFF = 99.63 %
PFHD =3.42E-09 (1/h)
MTTFD = 803 years
DC = 97.82 %
SFF = 99.57 %
PL e / CAT 4 according to EN/ISO 13849
SIL 3 according to EN 62061
PL d / CAT 2 according to EN/ISO 13849
SIL 3 according to EN 62061
The application for a specific PL,
category or SIL-CL requires a risk
analysis of the end-use application to
determine whether two incremental
encoders are sufficient.
These safety parameters were calculated
for the SNC 021 when used with a
incremental encoder. The safety
parameters of the entire machine must
be determined in the end application.
Reason for SIL 3 with single-channel use:
Because the high SFF value is greater than 99 %, SIL 3 can be accepted with a hardware
tolerance (HFT) of 0 according to EN 62061.
1-channel and 2-channel application:
The application for a specific PL, category or SIL-CL requires a correct
installation. Please note any normative requirements of the end application
(machine) for installation and selection of encoders.
The use of the specified parameters requires a risk analysis of the end
application, by which whether 2 incremental encoders is sufficient must be
determined.
For two-channel application, both incremental encoders must be monitored in
the application (SCP 011/111).
S-DIAS SAFETY SNC INCREMENTAL ENCODER SNC 021
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2.4 Compatibility
Compatibility
For compatibility of the S-DIAS Safety modules, see chapter "Compatibility of
S-DIAS Safety Modules" in the system handbook.
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3 Technical Data
3.1 I-encoder Specifications
Number of channels
2
Encoder
Incremental encoder with RS422 Interface with null position trace.
Input frequency
0.75 MHz
Counter frequency
3 MHz
Signal analysis
4x
Encoder resolution
maximum 16 bits
Encoder power supply
+5 V supply, short-circuit proof with monitoring function
and current measurement (+5 V is generated from +24 V at X3)
Status LED
yes
I-encoder current consumption
maximum 300 mA per encoder
3.2 Electrical Requirements
Supply voltage for the encoder
supply
+18-30 V
Current consumption of supply
voltage for the encoder supply
typically 162 mA/24 V
maximum 200 mA/30 V
Voltage supply from Safety bus
+12 V
Current consumption on the
Safety bus (+12 V supply)
typically 75 mA
maximum 90 mA
Voltage supply from S-DIAS bus
+24 V
Current consumption on the
S-DIAS bus (+24 V supply)
typically 33 mA
maximum 40 mA
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If this S-DIAS Safety module is connected to an SCP with several modules, the total
current of the S-DIAS Safety modules used must be determined and checked.
The total current of the +24 V supply cannot exceed 800 mA.
The total current of the +12 V supply cannot exceed 800 mA.
Si ce module de sécurité S-DIAS Safety est raccordé à un SCP avec plusieurs
modules, le courant total des modules de sécurité S-DIAS utilisés doit être déterminé
et vérifié.
Le courant total de l'alimentation +24 V ne peut pas dépasser 800 mA.
Le courant total de l'alimentation +12 V ne peut pas dépasser 800 mA.
The SNC 021 module can only be used in conjunction with an
SCP 011/SCP 111 that has been configured as a master CPU.
Le module SNC 021 ne peut être utilisé qu'en combinaison avec un module
SCP 011/SCP 111 lequel a été configuré comme processeur maître.
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3.3 Miscellaneous
Article number
20-896-021
Hardware version
2.x-3.x
Standard
Two-channel application: EN 62061SIL 3 or SIL CL 3
EN ISO 13849-1 PL e/Cat. 4
One-channel application: EN 62061 SIL 2 or SIL CL 2
EN ISO 13849-1 PL d/Cat. 2
UL 508 (E247993)
Approvals
CE, CULUS
3.4 Environmental Conditions
Storage temperature
-20 ... +85 °C
Environmental temperature
0 ... +50 °C
Humidity
0-95 %, non-condensing
Installation altitude above sea
level
0-2000 m without derating
> 2000 m with derating of the maximum environmental temperature by 0.5
°C per 100 m
Operating conditions
Pollution degree 2
EMC resistance
in accordance with 61000-6-7:2015 (Generic standards - Immunity
requirements for equipment intended to perform functions in safety-related
systems (functional safety) at industrial locations)
in accordance with EN 61000-6-2:2007 (industrial area)
(increased requirements in accordance with IEC 62061)
EMC noise generation
in accordance with EN 61000-6-4:2007 (industrial area)
Vibration resistance
EN 60068-2-6
3.5 mm from 5-8.4 Hz
1 g from 8.4-150 Hz
Shock resistance
EN 60068-2-27
15 g
Protection type
EN 60529
IP20
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4 Mechanical Dimensions
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5 Connector Layout
The connections of the +24 V supply (X3: pin 1 and pin 2) or the GND supply (X3: pin
3 and pin 4) are internally bridged. To supply the module, only one connection to a
+24 V pin (pin 1 or pin 2) and a GND pin (pin 3 or pin 4) is required. The bridged
connections may be used for further looping of the +24 V supply and the GND
supply. However, it must be taken into account that a total current of 6 A per
connection is not exceeded by the forward looping!
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5.1 Status LEDs
Bus Status
green
ON
bus communication OK
OFF
no supply available
BLINKING (5 Hz)
no communication
Safety Used
yellow
ON
can be set from the application
(e.g. the module LED can be set to blinking through the
visualization so that the module is easily found in the control
cabinet)
OFF
BLINKING (2 Hz)
BLINKING (4 Hz)
Encoder Status
green
ON
encoder signal OK
OFF
encoder is not in use
BLINKS
signal error was detected
Safe Status
green
ON
Safety of the Safe CPU provides invalid encoder values
OFF
encoder is not in use or
Safety provides invalid encoder values
DC OK
green
ON
+24 V input voltage for encoder supply OK
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5.2 Applicable Connectors
Connectors:
X1-X3: Connectors with spring terminals (included in delivery).
The spring terminals are suited for the connection of ultrasonically compacted (ultrasonically
welded) wires.
Connections:
Stripping length/sleeve length.
10 mm
Mating direction:
parallel to the conductor axis or circuit board
Conductor cross section rigid:
0.2-1.5 mm2
Conductor cross section flexible:
0.2-1.5 mm2
conductor cross section strands ultrasonically compacted:
0.2-1.5 mm2
Conductor cross section AWG/kcmil:
24-16
Conductor cross section flexible with ferrule without plastic
sleeve:
0.25-1.5 mm2
Conductor cross section flexible with ferrule with plastic sleeve:
0.25-0.75 mm2 (reason for reduction d2 of the
ferrule)
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5.3 Label Field
Manufacturer:
Weidmüller
Type:
MF 10/5 CABUR MC NE WS
Article number Weidmüller
1854510000
Compatible printer
Weidmüller
Type:
Printjet Advanced 230V
Article number Weidmüller
1324380000
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6 Wiring
6.1 Wiring Example
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6.2 Note
The input filters, which suppress noise signals, allow operation in harsh environmental
conditions. A careful wiring method is also recommended to ensure error-free function.
The following installation guidelines should be observed:
• Avoid parallel connections between input lines and load-bearing circuits.
• Protective circuits for all relays (RC networks or free-wheeling diodes)
• Correct wiring to ground
The ground bus should be connected to the control cabinet when possible!
Si possible la terre doit être connectée à l'armoire de commande!
Wiring and mounting must be performed with no voltage applied!
IMPORTANT:
The S-DIAS module CANNOT be connected/disconnected while voltage is applied!
Important!
Le module S-DIAS ne peut pas être inséré ou retiré sous tension.
7 RS422 Interface
The RS422 interface is internally connected in the component.
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8 Mounting
The S-DIAS modules are designed for installation into the control cabinet. To mount the
modules a DIN-rail is required. The DIN rail must establish a conductive connection with the
back wall of the control cabinet. The individual S-DIAS modules are mounted on the DIN rail
as a block and secured with latches. The modules must be mounted horizontally (module
label up) with sufficient clearance between the ventilation slots of the S-DIAS module blocks
and nearby components and/or the control cabinet wall. This is necessary for optimal cooling
and air circulation, so that proper function up to the maximum operating temperature is
ensured.
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Recommended minimum distances of the S-DIAS modules to the surrounding components
or control cabinet wall:
a, b, c … distances in mm (inches)
9 Disposal
For the disposal of the product, the respective guidelines, possibly country-specific, must be
observed and followed.
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10 Encoder Configuration
The maximum encoder frequency is defined with 750 kHz (at 1x edge analysis). This
corresponds to a maximum counter frequency or 1.5 MHz (at 4x edge analysis).
When selecting the encoder to install, this must be taken into consideration accordingly.
In the following table, the permissible speed in the rotary encoder for the respective
resolution based on the maximum encoder frequency can be seen.
Encoder Resolution
(Increments/Conversion)
Speed Scaling
Revolutions/Second
Revolutions/Minute
60
12.500
750.000
80
9.375
562.500
100
7.500
450.000
128
5.859
351.563
150
5.000
300.000
200
3.750
225.000
256
2.930
175.781
512
1.465
87.891
1024
732
43.945
2048
366
21.973
4096
183
10.986
This is only a sample of possible encoder resolutions.
With the following formulas, the highest permissible rotation speed (revolutions/min) can be
determined for an encoder with a resolution that is not listed in the table above.
Revolutions/sec:
Revolutions/min:
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Legend:
n
max
… highest permissible speed in revolutions/sec or revolutions/min.
f
max
… maximum encoder frequency of 750 kHz
res … encoder resolution according to the manufacturer data sheet.
If linear encoders are used or for example, a translation ratio must be included, as well as the
calculation for the maximum permissible speeds and the scaling parameters that must be
defined in the Safety Designer for each encoder, taken into consideration.
The following formula is thereby generated:
Legend:
v
max
… maximal possible, scaled speed
f
max
… maximum encoder frequency of 750 kHz
mul
position
… factor for converting the position of length (units parameter)
div
position
… divisor for converting the position of length (units parameter)
mul
speed
… factor for converting the speed or time base (speed multiplier parameter)
div
speed
… divisor for converting the speed or time base (speed divisor parameter)
Due to the 32-bit data width, a maximum value of 2,147,483,647 is generated for the upper
speed limit (the highest bit is used as the sign).
The following conditions result:
Legend:
f … Encoder frequency (with simple edge analysis)
Notes on position monitoring
If the encoder is set for position monitoring, (linear, rotation encoder), it must be taken into
consideration that the minimum and maximum value of the position must be monitored in the
application. The maximum value is dependent on the scaling parameters for calculating the
parameters and limited to 32 bits.
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11 Installing the Encoder
Line and encoder errors are diagnosed using, among other things, the measurement of the
encoder currents.
For this purpose, the preset values for measuring current must be defined in the system. The
current limits are defined in the automatic system automatically, so the user does not have to
predefine or configure any additional parameters.
In the unverified status of the system, the encoder currents are measured while starting the
system and used as temporary reference values. Based on the determined reference values,
the current limits are temporarily defined with ±25%. If a corresponding fluctuation in the
encoder currents due to a wiring fault is detected during movement, the system switches to
the Safe mode and the appropriate diagnostic codes are provided.
CAUTION!
Before the Safety system is labeled as verified, the wiring of the installed encoder must be
checked manually to ensure that the system operates error-free (the encoder operates
without fault).
During verification, which is run via the “Set Verified” button in the SafetyDesigner or the
validation button on the Safe CPU, the actual current measurements are used to determine
the permissible limit values for the encoder current and then stored in the Safe CPUs remnant
data. These limit values are based on the measured value ±25 %.
After successful validation, the encoder currents are monitored using the current values
stored in the Safe CPU. When in verified status, the upper or lower limits are exceeded, the
system changes to safe mode and the appropriate diagnostic code for error analysis is again
provided.
In the standard application, the actual and preset current values are provided via the
hardware classes.
CAUTION! Exchanging the encoder
Basically, the Safety system cannot detect an encoder exchange when no power is applied.
The parameters of the new encoder could be different from the replaced encoders with regard
to the currents, whereby it is no longer possible guarantee the appropriate monitoring of the
newly installed encoder.
In such a case, the system must be reverified. This means reconfiguring the Safe CPU via
the SafetyDesigner or µSD card and verifying (see Safety System manual)
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12 Important Notes for Two-channel Application
When using the SNC 021 module in compliance with SIL 3 or SIL CL 3 according to EN
62061 and PL e, Cat. 4 according to EN ISO 13849-1, it must be taken into consideration
that for 2-channel application, a part of the possible wiring errors can only be detected by
comparing the measurement results of both encoders in the Safety application of the Safe
CPU. The inversion of signal lines A+ with A- as well as B+ with B- are one of these errors.
Mechanical errors, such as a detached coupling can also be detected only in the Safety
application of the Safe CPU.
To meet the requirements of the diagnostic coverage ratio, both encoders must be
synchronously monitored in the Safety application of the Safe CPU.
For synchronous monitoring, the functional Safety block SF_SkewMonitor (see chapter
“Numerical Function Blocks” in the SafetyDesigner tool help) must be placed in the Safety
project and used according to the documentation.
The inputs S_ChnValue1 and S_ChnValue2 of the functional Safety blocks must be wired
with the input information _Chn1Value and S_Chn2Value (synchronous monitoring of the
position) or alternatively, with S_Chn1Speed and S_Chn2Speed (synchronous monitoring of
the speed) of the SNC 021 module.
The required tolerance must be defined by the user. During synchronous monitoring via the
position, it must be taken into consideration that if there is the possibility of a position overflow,
the scaling parameter can cause position jumps. In such a case, the scaling parameter for
calculating the position should be left at the default settings (factor and divisor
are 1), or synchronous monitoring performed using the speed.
If the system is not in Safe mode, synchronous monitoring must be performed
according to the previously mentioned criteria
Si le système n'est pas en mode Safe, une surveillance synchrone doit être effectuée
selon les critères mentionnés précédemment.
If all mechanical error sources can be excluded due to the coupling type and the type of
encoder used (e.g. defective encoder mechanics), monitoring the direction of both encoders
is then sufficient.
This can be run in the Safety application using the functional Safety block
SF_DirectionMonitor (see chapter “Numeric Function Blocks” in the SafetyDesigner tools
help) and in this case, performed for both encoders.
If synchronous monitoring is not performed in the Safety application as described
here, the machine manufacturer must then prove that the requirements of SIL 3 or
SIL CL 3 according to EN 62061 and PL e, Cat. 4 according to EN ISO 13849-1/-2 are
met if required for the machine.
SNC 021 S-DIAS SAFETY SNC INCREMENTAL ENCODER
Page 30 02.12.2019
Si la surveillance synchrone n'est pas effectuée par le logiciel de sécurité comme
décrit dans la présente documentation, le constructeur de la machine doit alors
prouver que les exigences des normes SIL 3 ou SIL CL 3 selon EN 62061 et PL e, Cat.
4 selon EN ISO 13849-1/-2 sont respectées si la machine le requiert.
S-DIAS SAFETY SNC INCREMENTAL ENCODER SNC 021
02.12.2019 Page 31
13 Supported Cycle Times
The SNC 021 supports different cycle times. If variable sample points are deactivated, the
IOs are updated with 4 kHz at cycle times of 250 µs to 32 ms. If the cycle time is lower than
250 µs, the IOs are updated with 3 kHz and PDO data are transmitted in a millisecond cycle.
13.1 Cycle Times below 1 ms (in µs)
50
100
125
200
250
500
x x x x x
x
13.2 Cycle Times equal to or higher than 1 ms (in ms)
1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
x x x x x x x x x x x x x x x
x
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
x x x x x x x x x x x x x x x
x
SNC 021 S-DIAS SAFETY SNC INCREMENTAL ENCODER
Page 32 02.12.2019
Documentation Changes
Change date
Affected page(s)
Chapter
Note
20.09.2018
5 Connector Layout
Note added
15.11.2018
15
3.3 Miscellaneous
UL instead of UL in preparation
19.02.2019
28
11 Installing the
Encoder
Tolerance changed from +25 % to ±25 %
02.04.2019
12
16
all
2.3 Safety-Relevant
Parameters
3.4 Environmental
Conditions
Correction of the safety-relevant parameters
Corrections environmental conditions
Corrections due to CE
08.08.2019
Entire document
“safety-related” replaced
14.11.2019
13 Supported Cycle
Times
Chapter added
02.12.2019
2.3 Safety-Relevant
Parameters
Values updated
S-DIAS SAFETY SNC INCREMENTAL ENCODER SNC 021
02.12.2019 Page 33
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