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3.4.2
Electrical installation - general information
The flame detector can operate via a standard 3 or 4 wire termination and has
two types of alarm output available simultaneously:
–
0 - 20 mA
–
Relay (alarm and fault)
Event
Power/detector fault
Low supply voltage fault
Optical fault
Healthy condition
Alarm
*Aux alarm - configurable
Over-range
Notes:
–
The tolerance on the above outputs is +/-0.3 mA current with a maximum
loop resistance of 500 ohms.
–
Additional 0 - 20 mA values are configurable and must be specified when
ordering if required. The optical fault signal may be configured at 2 mA as
opposed to 1.5 mA and the alarm signal may be increased to 20 mA.
–
The 0 - 20 mA signal has HART
give access to more diagnostic information.
The following illustration shows the internal connections of the alarm and fault
relay contacts and jumpers. Each field connection is also shown on this
illustration for clarity.
1)
The flame detector can be factory-configured with an Aux alarm delay (20 mA) of between 0 s
and 10 s in 1 s steps over and above the normal response times of the 18 mA alarm signal. If the
Aux alarm signal is delayed the 18 mA alarm signal will precede the 20 mA signal giving the nor-
mal response times as tested by Factory Mutual to FM3260. If the 20 mA alarm signal is delayed,
it is considered an Aux alarm level.
Instructions for use
|
Output (in mA)
0
1
1.5
4
18
20
21
®
7 protocol superimposed on top of it to
The end-of-line and alarm resistances are to be calculated based on the
requirements of the control system.
CAUTION
Risk of damage to the device!
The flame detector must be properly grounded. Failure to do so may cause
electrical interference in the equipment.
Metric cable entries are fitted with an internal stop that results in the threads
being visible after assembly. Over-tightening may result in damage to both the
cable entry and the gland.
► Properly ground the flame detector.
► Do not over-tighten the cable glands.
A 2 m helix should be allowed in the flame detector cabling. This allows the
detector to be repositioned if local obstructions, such as pipework and cable
trays, block the detector's view of the local hazard.
1)
|
en
Mounting
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