Slide background

Il nuovo Standard ISO 24119 e il massimo PL raggiungibile in caso di serie di dispositivi di interblocco

ID 1610 | | Visite: 10690 | Documenti Estratti NormePermalink:

ISO/DTR 24119
Safety of machinery - Evaluation of fault masking serial connection of guard interlocking devices with potential free contacts.

This is currently under committee review, with an expectation that it will be available quite soon as ISO/TR 24119.

This TR has not been published but it will deal with.

The Technical Report illustrates and explains principles of fault masking in applications where multiple interlocking devices with potential free contacts are connected in series to one logic unit which does the diagnostics.

It provides also a guide how to estimate the probability of fault masking and the maximum DC for the involved position switches.

In simple terms, if we have more than one frequently opened guard (once per hour) the level of Diagnostic Coverage falls to zero, which in EN ISO 13849-1 results in a maximum PLc.

It remains to be seen exactly what ISO/PDTR 24119 has to say about the maximum PL achievable when several infrequently operated guards are connected, but it is very likely to be PLd where careful analysis is possible (for example, the number of guards, the type of switches, type of wiring, distance between guards, and accessibility of guards), otherwise it is more likely to be PLc.

It is definitely not possible to achieve PL e with more than one guard switch connected in series, at least not when using volt-free based interlock switch technology.

Early signs are that the technical report ISO/PDTR 24119 will provide two methods for evaluating the extent to which diagnostic coverage is impacted by masking:

1. Simplified method for the determination of the maximum achievable DC

Table 1 provides a simplified approach for the determination of the maximum achievable DC taking into account the probability of masking.

If the maximum achievable DC resulting from the application of this table does not meet the required level, the more detailed approach given in 2 may be more suitable - but this is not ideal.

2. Regular method for the determination of the maximum achievable DC

2.1 Estimation of the fault masking probability

The probability of fault masking is dependent on several parameters that should be considered, including:

  • Number of series connected devices
  • Actuation frequency of each movable guard
  • Distance between the movable guards
  • Accessibility of the movable guards
  • Number of operators

The maximum achievable DC depends on the fault masking probability level (FM) and the type of cabling used in combination with the switch arrangement and the diagnostic capabilities of the overall system to detect faults.

Tables 3 to 5 show the maximum reachable DC depending on those parameters.

In any case, if it is foreseeable that fault masking will occur (eg multiple movable guards will be open at the same time as part of normal operation or service), then the DC is limited to none.

It is beyond the scope of this article to go into the details of tables 3 and 5 referred to above, and it is recommended that, instead, the 'simplified method outlined in 2 above is used.

Fonte: Pilz

Tags: Normazione EN ISO 14119

Articoli correlati

Ultimi archiviati Normazione

UNI EN 1757 2022
Lug 05, 2022 45

UNI EN 1757:2022

UNI EN 1757:2022 ID 17019 | 05.07.2022 / In allegato Preview Sicurezza dei carrelli industriali - Carrelli industriali con piattaforma a propulsione con operatore a terra La norma si applica ai carrelli industriali con piattaforma a propulsione con operatore a terra con una portata nominale fino a… Leggi tutto
Norme armonizzate Direttiva imbarcazioni diporto 12 2017
Giu 29, 2022 71

Decisione di esecuzione (UE) 2022/1029

Decisione di esecuzione (UE) 2022/1029 / Norme armonizzate imb. da diporto Giugno 2022 Decisione di esecuzione (UE) 2022/1029 della Commissione del 28 giugno 2022 che modifica la decisione di esecuzione (UE) 2019/919 per quanto riguarda le norme armonizzate relative ai dati principali delle unità… Leggi tutto
ISO 16103 Imballaggi di materie plastiche riciclate per il trasporto di merci pericolose
Giu 27, 2022 64

UNI EN ISO 16103:2005

UNI EN ISO 16103:2005 / Imballaggi di materie plastiche riciclate per il trasporto di merci pericolose Imballaggi - Imballaggi per il trasporto di merci pericolose - Materie plastiche riciclate La presente norma è la versione ufficiale in lingua inglese della norma europea EN ISO 16103 (edizione… Leggi tutto
Giu 24, 2022 64

CEI EN 50554

CEI EN 50554 Norma di base per la valutazione in-situ di un impianto di radiodiffusione con riferimento all'esposizione ai campi elettromagnetici a radiofrequenza Data: Aprile 2022Classificazione CEI: 106-29_______ La pubblicazione contiene immagini e testo che, per una migliore lettura del… Leggi tutto
ISO 23601 Ed  2020
Giu 18, 2022 536

ISO 23601:2020

ISO 23601:2020 ID 16879 | 19.06.2022 / Preview in attachment ISO 23601:2020Safety identification - Escape and evacuation plan signs This document establishes design principles for displayed escape plans that contain information relevant to fire safety, escape, evacuation and rescue of the… Leggi tutto
Giu 12, 2022 98

CEI EN 62108: 2018

CEI EN 62108: 2018 Moduli e sistemi fotovoltaici a concentrazione (CPV) - Qualifica di progetto e approvazione di tipo; Classificazione: CEI 82-30 Data pubblicazione: 2022-04 La presente Norma specifica le prescrizioni minime per la qualifica di progetto e l’approvazione di tipo di moduli e sistemi… Leggi tutto

Più letti Normazione