GASSONIC Observer-i - Relay Ratings; Alarm Relay Output; Ma Output

GASSONIC OBSERVER-i
20
• Alarm Relay Output
Can be configured as normally energized/de-energized
• Errors Relay Output
Always configured as normally energized
• 4-20 mA Analog Output
Can be configured as source or sink
• Serial Digital Communication
Configurable as Dual Modbus or Single Modbus and HART (optional)
The user needs to determine the appropriate output method.
4.3.12. Relay Ratings
 8 A @ 250 VAC
 See graph in Section 8.2.1 for DC ratings
4.3.13. Alarm Relay Output
In Classic Mode, the SPL alarm trigger shall be set at least 6 dB higher than the background noise.
When using the Alarm Relay the trigger level setting should be set internally by means of an adjustable
trigger level in 5 dB steps between 49 and 99 dB. When using the Analog Output, the trigger level
should be set in the fire & gas system. The factory default setting is 79 dB.
In Enhanced Mode, the internal dB setting is referred to as the ANN Sensitivity Level. This is set
internally by means of the magnet on the display in 5 dB steps between 49 and 99 dB. The ANN
Sensitivity Level is a dB level which keeps the detector from going into alarm on a positive ANN event,
unless the SPL has past the preset ANN Sensitivity Level.
An alarm delay time is implemented to eliminate spurious alarms due to short background noise peaks.
This delay time is particularly important in Classic Mode, when ANN is not used for gas detection. The
delay time can be set between 0 and 240 seconds. The factory default setting for delay is 2 seconds in
Enhanced Mode and 10 seconds in Classic Mode. The delay can alternatively be configured via the
“Fire and Gas Panel”, Modbus or HART.
When a gas leak occurs in the detector’s coverage area and the detector is in Classic Mode, the trigger
level will be reached, the LED in the optical link window will be illuminated, and the alarm relay timer
will be started. When the delay times out, the unit will go into alarm mode.
When a gas leak occurs in the detector’s coverage area and the detector is in Enhanced Mode, the
ANN will calculate the probability of a true gas leak and will result in a positive. When the ANN
Sensitivity Level is also reached, the LED in the optical link window will be illuminated and the alarm
relay timer will be started. When the delay times out, the unit will go into alarm mode.
An alarm mode results in the following:
• The dB value preceded by an “A” (“C” in Classic mode) will flash on the display
• The alarm relay will activate
• The analog output will change according to the output mode (see Table 1)
• An event will be recorded
4.3.14. 4-20 mA Output
In normal operation, the output is between 4 and 20 mA. When using this output method in Classic
Mode, the SPL trigger is set at least 6 dB higher than the background noise, and the alarm delay time