Spectrex Quasar 900 Open-Path Gas Detection System Manual de usuario descargar pdf (Pagina 25)

Operational Modes 13

3 Operating Modes

➣ In this chapter…

Operational Modes

page 13

Visual Indicators

page 15

Output Signals

page 15

System Setup

page 16

3.1 Operational Modes

The Quasar 900 has four operational modes:

 Normal Mode, page 13

 Maintenance Call Mode (3mA Output), page 13

 Fault Mode, page 14

 Zero Calibration Mode (1mA Output), page 14

3.1.1 Normal Mode

This mode is used for gas detection. In normal mode, the following statuses

are possible:

 Normal - Signal received from gas detection is at safe levels.

 Warning* - Gases have been detected at warning levels.

 Alarm* - Gases have been detected at alarm levels.

Note: For the standard 0-20mA output, the Warning and Alarm levels are

not relevant. The user chooses these alarm levels at the controller. The

output Detector will be 4mA at zero reading and 20mA for full-scale reading.

Warning and Alarm states are relevant where the stepped 0-20mA output is

used and will energize the warning and alarm relays.

If the RS485 output is used, the Detector changes its status from ‘N’ to ‘W’

at Warning level and to ‘A’ at Alarm.

3.1.2 Maintenance Call Mode (3mA Output)

This mode indicates low signal or low signal ratio that may be caused by a

dirty window; misalignment; poor source or that one of the Detectors

parameters is at the ‘limit’ value.

The Detector continues to function and reads any gas present, but provides

a (3mA) pre-warning signal that a maintenance procedure is required.

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Spectrex Quasar 900 Open-Path Gas Detection System Manual de usuario Pagina 25