D e t e c t i o n
NEO Photo-ionization detector
User Manual
D e t e c t i o n
16
6.3.3 ALARM SETTING
During each measurement period, the gas concentration is compared with
the programmed alarm limits (Low, High, TWA and STEL). If the concentration
exceeds any of the preset limits, the loud buzzer and red flashing LED are
activated immediately to warn of the alarm condition. Press the Right key to enter
the Alarm Setting menu.
Alarm Limits
In this menu, the High, Low, STEL, and the
TWA alarm limits can be changed. Press the
Right key to enter the Alarm Limits menu.
High Alarm
The default High Alarm limit is set by the instrument to match the
value for the current measurement gas. To change the High Alarm
limit press the Up or Mode key to increase or decrease each digit’s
value, and the Right or Left key to move the cursor. Move the cursor
to ‘√’ after the setting is complete, and press Up to save and exit.
Low, STEL and TWA Alarms
Set the Low, STEL and TWA Alarm limits in the same manner as described above for the High Alarm limit.
Note: All default alarm limits depend on the measurement gas and are expressed in ppm.
Alarm Mode
There are two selectable alarm modes:
1. Latched
When the alarm is triggered, it stays on even when the concentration falls back below the alarm limit.
The alarm must be stopped manually by pressing the Right key. The latched setting only controls
High, Low, STEL, and TWA alarms.
2. Automatic Reset
When the alarm condition is no longer present, the alarm stops automatically.
Alarm settings
The buzzer and light alarms can be programmed to be on or off individually or in combination. The
choices are:
• Both on
• Light only
• Buzzer only
• Both off
Press the Up or Mode key to step from one option to the next. Then press Right to make a selection
followed by Left to save and exit.
