Mitsubishi Electric CC-Link IE-NZ2GNSS2-8D User Manual page 158

Precautions for use of safety programmable controller
Users must prove that their entire safety system complies with the safety standards and the Machinery Directive. The third-
party certification organization will validate the safety of product for the entire safety system, including a safety programmable
controller and safety components.
■Target failure measure (PFDavg/PFH) calculation
To establish a safety system, calculate the target failure measure (PFDavg/PFH) for each safety application (safety function)
based on the PFDavg/PFH values of the safety programmable controller and connected safety components. The target failure
measure (PFDavg/PFH) is the reliability target value for each Safety Integrity Level (SIL) defined in IEC 61508 and can be
calculated by the following formula.
PFDavg/PFH = A + B + C + D......Calculation formula of PFDavg/PFH
Variable Definition
A Total PFDavg/PFH of the safety CPU module, power supply module, base unit, and CC-Link IE TSN master module
B PFDavg/PFH of the CC-Link IE TSN remote I/O module (with safety functions)
(1) When safety input device(s) and safety output device(s) are connected to the same CC-Link IE TSN remote I/O module (with safety
functions): B = B1
(2) When safety input device(s) and safety output device(s) are connected to the different CC-Link IE TSN remote I/O modules (with safety
functions): B = B1 + B2
B1 PFDavg/PFH of the CC-Link IE TSN remote I/O module (with safety functions) to which safety input device(s) is connected
B2 PFDavg/PFH of the CC-Link IE TSN remote I/O module (with safety functions) to which safety output device(s) is connected
*1
C PFDavg/PFH of safety input device(s)
*1
D PFDavg/PFH of safety output device(s)
*1 For the values of PFDavg/PFH, refer to the manuals for the safety components used.
The following table lists the PFDavg/PFH of safety remote I/O modules.
Module
NZ2GNSS2-8D
NZ2GNSS2-8TE
NZ2GNSS2-16DTE
*2 Proof test interval is 5 years.
■PL evaluation described in ISO 13849-1
For the PL evaluation described in ISO 13849-1, use the MTTF
diagnostic coverage) listed in the following table.
Module
NZ2GNSS2-8D
NZ2GNSS2-8TE
NZ2GNSS2-16DTE
APPX
156
Appendix 5 EMC and Low Voltage Directives
PFDavg
-5
1.3810
-5
1.3710
-5
1.4610
(mean time to dangerous failure) and the DCavg (average
D
MTTF
D
243 years
271 years
161 years
*2
PFH(/h)
-9
6.1210
-9
5.4910
-9
9.2510
DCavg
97.0%
96.8%
97.7%