monitoring of the feedback circuit in the safety ?· illustrate the monitoring of the feedback...

Download Monitoring of the Feedback Circuit in the Safety ?· illustrate the monitoring of the feedback circuit.…

Post on 29-Jul-2018

212 views

Category:

Documents

0 download

Embed Size (px)

TRANSCRIPT

  • Monitoring of the Feedback Circuit in the Safety Program

    Safety Integrated

    https://support.industry.siemens.com/cs/ww/en/view/21331098

    Siemens Industry Online Support

    https://support.industry.siemens.com/cs/ww/en/view/21331098

  • Warranty and Liability

    Monitoring Feedback Circuit S7-1500 Entry-ID: 21331098, V3.1, 01/2017 2

    S

    iem

    en

    s A

    G 2

    01

    7 A

    ll ri

    gh

    ts r

    ese

    rve

    d

    Warranty and Liability

    Note The Application Examples are not binding and do not claim to be complete regarding the circuits shown, equipping and any eventuality.The Application Examples do not represent customer-specific solutions.They are only intended to provide support for typical applications.You are responsible for ensuring that the described products are used correctly.These Application Examples do not relieve you of the responsibility to use safe practices in application, installation, operation and maintenance.When using these Application Examples, you recognize that we cannot be made liable for any damage/claims beyond the liability clause described.We reserve the right to make changes to these Application Examples at any time without prior notice. If there are any deviations between the recommendations provided in these Application Examples and other Siemens publications e. g. catalogs the contents of the other documents have priority.

    We do not accept any liability for the information contained in this document. Any claims against us based on whatever legal reason resulting from the use of the examples, information, programs, engineering and performance data etc., described in this Application Example shall be excluded. Such an exclusion shall not apply in the case of mandatory liability, e.g. under the German Product Liability Act (Produkthaftungsgesetz), in case of intent, gross negligence, or injury of life, body or health, guarantee for the quality of a product, fraudulent concealment of a deficiency or breach of a condition which goes to the root of the contract (wesentliche Vertragspflichten). The damages for a breach of a substantial contractual obligation are, however, limited to the foreseeable damage, typical for the type of contract, except in the event of intent or gross negligence or injury to life, body or health. The above provisions do not imply a change of the burden of proof to your detriment. Any form of duplication or distribution of these Application Examples or excerpts hereof is prohibited without the expressed consent of Siemens Industry Sector.

    Security information

    Siemens provides products and solutions with Industrial Security functions that support the secure operation of plants, systems, machines and networks. In order to protect plants, systems, machines and networks against cyber threats, it is necessary to implement and continuously maintain a holistic, state-of-the-art Industrial Security concept. Siemens products and solutions only form one element of such a concept. Customer is responsible to prevent unauthorized access to its plants, systems, machines and networks. Systems, machines and components should only be connected to the enterprise network or the internet if and to the extent necessary and with appropriate security measures (e. g. use of firewalls and network segmentation) in place. Additionally, Siemens guidance on appropriate security measures should be taken into account. For more information about Industrial Security, please visit http://www.siemens.com/industrialsecurity.

    Siemens products and solutions undergo continuous development to make them more secure. Siemens strongly recommends to apply product updates as soon as available and to always use the latest product versions. Use of product versions that are no longer supported, and failure to apply latest updates may increase customers exposure to cyber threats. To stay informed about product updates, subscribe to the Siemens Industrial Security RSS Feed under http://www.siemens.com/industrialsecurity.

    http://www.siemens.com/industrialsecurityhttp://www.siemens.com/industrialsecurityhttp://www.siemens.com/industrialsecurity

  • Table of Contents

    Monitoring Feedback Circuit S7-1500 Entry-ID: 21331098, V3.1, 01/2017 3

    S

    iem

    en

    s A

    G 2

    01

    7 A

    ll ri

    gh

    ts r

    ese

    rve

    d

    Table of Contents Warranty and Liability ................................................................................................. 2

    1 Task ..................................................................................................................... 4

    2 Solution............................................................................................................... 4

    2.1 Overview............................................................................................... 4 2.2 Hardware and software components ................................................... 6 2.2.1 Validity .................................................................................................. 6 2.2.2 Components used ................................................................................ 6

    3 Basics ................................................................................................................. 8

    3.1 Basic terms ........................................................................................... 8 3.2 Functional safety .................................................................................. 9 3.3 Feedback circuit ................................................................................. 10

    4 Mode of Operation ........................................................................................... 11

    4.1 General overview ............................................................................... 11 4.2 Monitoring the emergency-stop control devices ................................ 13 4.3 Monitoring the feedback circuit .......................................................... 14 4.4 Data exchange between standard user program and safety

    program .............................................................................................. 15

    5 Configuration and Settings............................................................................. 16

    5.1 Settings of the DI ................................................................................ 16 5.2 Settings of the F-DI ............................................................................ 17 5.3 Settings of the F-DQ ........................................................................... 19

    6 Installation and Commissioning .................................................................... 20

    7 Operating the Application ............................................................................... 23

    8 Evaluation of the Safety Function .................................................................. 25

    8.1 Standards ........................................................................................... 25 8.2 Safety functions .................................................................................. 25 8.3 Evaluation according to IEC 62061 .................................................... 26 8.4 Evaluation according to ISO 13849-1 ................................................ 27

    9 Links & Literature ............................................................................................ 29

    10 History............................................................................................................... 29

  • 1 Task

    Monitoring Feedback Circuit S7-1500 Entry-ID: 21331098, V3.1, 01/2017 4

    S

    iem

    en

    s A

    G 2

    01

    7 A

    ll ri

    gh

    ts r

    ese

    rve

    d

    1 Task

    A machine executing dangerous movements is controlled via a fail-safe controller and switched by means of contactors. In order to protect the operating personnel, technical safety functions (e. g. an emergency-stop control device and a safety door) are implemented on the machine. The correct functioning of the contactors shall be monitored in order to ensure a high diagnostic coverage and, thus, a high SIL (safety integrity level according to IEC 62061) or PL (performance level according to ISO 13849-1).

    2 Solution

    2.1 Overview

    Schematic layout

    Monitoring the actuators represents a diagnostic function and significantly contributes to the SILCL (SIL claim limit) or PL of the corresponding subsystem. For electromechanical components (e. g. relays or contactors), a positively driven auxiliary contact often is fed back to the controller and then evaluated. This process is referred to as monitoring of the feedback circuit or readback of the contactors.

    Figure 2-1 Typical wiring of an actuator and its feedback circuit

    Q1

    F-DQDI

    This is particularly required for a redundant setup. If one of the two contactors welds (without this being noticed), the two-channel system would become a single-channel system.

    Instead, the welding will be detected and it will be prevented that the system is switched on again until the error is eliminated.

  • 2 Solution

    Monitoring Feedback Circuit S7-1500 Entry-ID: 21331098, V3.1, 01/2017 5

    S

    iem

    en

    s A

    G 2

    01

    7 A

    ll ri

    gh

    ts r

    ese

    rve

    d

    Setup

    In this application example, two machine parts are switched separately in order to illustrate the monitoring of the feedback circuit. Only the affected machine part shall be switched off via t

Recommended

View more >