SIL-2 Features
80
SharpEye™
UV Flame Detectors User Guide
E.1.2.2
Using the 0
–20mA Interface for Alerting
•
The following parameters should be set:
•
Automatic BIT test = on
•
Connected to 0
–
20mA Terminals
•
The following allowed output current must be supervised with an accuracy of
± 5%:
•
Normal State = 4mA
•
Warning State = 16mA
•
Alarm State = 20mA
•
The receiving device must be programmed to indicate a fault condition when
current levels reach overcurrent or undercurrent.
E.1.2.3
Using the Alarm Relay Contact for Alerting
•
The following parameters should be set:
•
Automatic BIT Test = on
•
Connected to N.C. contact of alarm relay terminals
•
Connected to fault relay terminals
•
The relay contacts (“alarm” and “faulty relay”) must be protected with a fuse
rated at 0.6 of the nominal specified relay contact current.
•
The maximum contact rating that is allowed per SIL-2 is 30VDC.
•
The contact of the alarm relay opens if there is a fire alarm.
•
During the forwarding and evaluation of the alarm, the relay contact opens.
•
The alarm relay can be used as low demand only.
E.1.2.4
Other
•
The complete function of the flame detector (flame detection, function of the
0
–
20mA interface, and the relays must be examined at least every 6 or 12
on page 79), or whenever the flame
detector must be switched off and on.
•
The window of the sensor must be examined at appropriate time intervals for
partial contamination.
Caution:
The HART and the RS-485 interfaces must not be used for the
transmission of safety-related data.
