EUCHNER AS-i Safety Monitor for 2 AS-i circuits - Manual (Page 18)

18 Subject to reasonable modifications due to technical advances Id.-No.: 103336 Issue date - 24.10.2008 EUCHNER GmbH + Co. KG
Kohlhammerstraße 16 • D-70771 Leinfelden-Echterdingen Tel. +49/711/75 97-0 • Fax. +49/711/753316
AS-i Safety Monitor for 2 AS-i circuits
Spezifications
4.2 Consideration of failure probability according to IEC 61 508
To allow calculation of failure probability for the entire system, the AS-i Safety
Monitor returns a component which depends on the maximum uninterrupted
switch-on time of the output circuit(s).
This results in the following table:
The switch-on time describes the period of time until the safety function was re-
quested, or the maximum period of time between two executed safety checks.
During this check, safe shutdown is tested by actuating every safe sensor.
The total operating time describes the safety system's service life from commis-
sioning to disassembly; it is used as the basis for calculating the failure probabili-
ty.
Together with the failure probabilities of the other components used in the safety
system (e.g. AS-i slaves) it is then possible to determine the overall failure proba-
bility. The resulting value can be used for categorising the safety system under
the respective safety level in accordance with IEC 61 508.
4.3 Scope of delivery
The basic unit consists of:
AS-i Safety Monitor for 2 AS-i circuits.
The following accessories are available:
Software CD with
• ASIMON 3 G2 communication software for Microsoft® Windows Me/NT/
2000/XP/Vista
®
• System manual in PDF format (Adobe® Acrobat Reader® Version 5.x or
newer is required for viewing the files)
Failure probability on request depending on switch-on time
Switch-on time Total operating time PFD
12 months 10 years <
9,25 x 10
-6
Probability of failure per hour
Switch-on time Total operating time PFH
12 months 10 years < 5,36 x 10 -9