Spectrex 40/40U-UB - UV Flame Detector - Manual (Page 77)

40/40UB Flame Detector 65
E SIL-2 Features
➣ In this appendix…
40/40UB Flame Detector page 65
E.1 40/40UB Flame Detector
This appendix details the special conditions to comply with the requirements
of EN 61508 for SIL 2.
The 40/40UB Flame Detector can only be used in low or high demand mode
applications, see IEC 61508.4, Chapter 3.5.12.
E.1.1 Safety Relevant Parameters
Perform the following functional checks of the detector every 30 days:
 HFT: 0
 PFD: 2.5 x 10 -5 (≈ 0.2% of SIL-2) if only Alarm Relay is used for
alerting.
 PFD: 2.8 x 10 -5 (≈ 0.3% of SIL-2) if 4-20mA interface is used as alarm.
 SFF: 97% fulfills the conditions of EN 61508 for SIL2
E.1.2 Guidelines for Configuring, Installing, Operating and
Service
The alert conditions according to SIL 2 can be implemented by an:
 Alert signal via 20mA current loop
or
 Alert signal via alarm relay and the fault relay
E.1.2.1 Conditions for Safe Operating
1 The flame detector shall consist only of the approved hardware and
software modules.
2 The 24V power supply must fulfill the requirements for PELV / SELV of
EN 60950.
3 The automatic BIT (Built-In-Test) must be activated.
4 The set-up parameters must be verified (as described in
Using the 0-20mA Interface for Alerting on page 65, point 1 and in Using
the Alarm Relay Contact for Alerting on page 66, point 1) and the
function of the 40/40 Flame Detector (flame detection, function of the
0-20mA interface, relay functions) must be checked completely.