Ma Loop Status; Relay Signalling; Normal Operation; Operation During Fault - Honeywell SEARCHZONE SONIK SZSK-SMG Series Technical Manual

8.2.2 mA Loop Status
The Searchzone Sonik is equipped with a 4-20 mA loop output which can operate in source or sink mode. Source and sink modes are
configured by wiring. For more information see the wiring diagram in Electrical Installation section. This output is a safety-related output
and is compatible for use in SIL 2 applications. Normal operation and alarm conditions are indicated between 4 to 20 mA, depending
on configuration.
The mA Loop offers two modes of operations:
1) Proportional to the detected sound pressure level.
2) Discrete, where the output will switch between distinct levels, based on detector status.
Fault and Inhibit indications are signalled with values lower than 4 mA, Over-range indications are signalled with value higher than
20 mA. Output levels of the 4-20 mA loop are configurable,
See the following table for output levels:
Mode
Discrete Mode
Fault
Inhibit
Warning
Normal
Pre-alarm
Alarm
Over-range
8.2.3 Relay Signalling
The Searchzone Sonik is equipped with three independent relays, designated for Fault, Alarm1 and Alarm2. These relays are safety-
related outputs and are compatible for use in SIL1 applications. The Fault relay is used for indication of various fault conditions; the
Alarm1 and Alarm2 relays are used to indicate alarm conditions. All the relays are configurable, giving an option of Normally Energised
/ De-energised and latching / non-latching of events.
CAUTION
Fault relay will be triggered when user performs Inhibit operation.
8.3 Normal Operation
During normal operation, the 4-20 mA output represents 0 -100% sound pressure level range, depending on the selected mode and
the SPL level.
The output is:
1) Linear within the range of SPL in Proportional mode
2) 4 mA in Discrete mode
Analog outputs lower than 4 and higher than 20 mA represent diagnostic information. The fault relay in this mode is normally energized
and the visual indicator is lit steady green.
8.4 Operation During Fault
If Fault is indicated the visual indicator starts to flash in yellow, the fault relay is de-energized and 4-20 mA loop is set to 1 mA.
NOTE:
HART communication requires >1 mA current output to support transmission. If the fault level is configured to be below 1 mA, HART
communications will cease.
PN 2331M1220 Issue 1
Default Value (mA)
Proportional Mode
1
2
3
4 Proportional to
sound pressure
level
16 Not available
20 Not available
21
Searchzone Sonik − Technical Manual
Min Value (mA) Max Value (mA)
0
1
1
4
4
4
20
8 Operation
3.6
3.6
4
20
20
20
22
40
11/2018