ENMET ISA-44-2OD - Manual (Page 7)

ISA-44-2-OD ENMET Corporation
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2.2 External Features
See Figure 1 for the outside front panel of the instrument:
Feature Description
Power Indictor
(Green Light) When the green light for a channel is on, the unit is operating normally; that is, there is no alarm
condition. When this light is off, the channel is in alarm or the power to the channel has been interrupted.
Visual Alarms Red Light: Visual alarm signal for high-level gas concentration. Relay contacts can also be attached here
for activating remote signals.
Amber Light: Visual alarm signal for low-level gas concentration. Relay contacts can be hooked up to
activate remote signals.
Meters Two gas concentration meters and one oxygen concentration meter. The scale is marked in parts per
million (ppm) for toxic gas detection, percent lower explosive limit (%LEL) for combustible gas, and
percentage of oxygen (% oxygen) in air. The "ppm" and "%LEL" meters are non-linear devices;
therefore the scales do not express specific gas concentrations for regions between the alarm points.
Do Not infer exact readings from unmarked regions of these meter scales.
Audio Alarm (Horn) Audio alarm (2900 Hz,95 dB at 2 ft.). The audio alarm is activated when the unit is in alarm.
Operation Switch A rotary switch for:
§ OPERATE – Normal Operation
§ HORN OFF – Disable Audio Alarm
§ PURGE ON – (sensor temperature control) Purge ON to clean (purge) sensor surface of absorbed
contaminants (sensor hot).
Switch Indicator (Red) When the light is on, Indicates Operation Switch is not in OPERATE
Oxygen Gain Allows user to adjust meter reading with a screwdriver. Normal fresh air concentration is 20.9% but the
meter will periodically show a variation due to atmospheric conditions.
Do Not adjust the oxygen gain until the oxygen cell (sensor) has been in fresh air for at least 15 minutes.
N OTE : All monitoring channels work independently. When one alarm is activated, the others are not affected and
continue monitoring without further adjustment.
Figure 1: External Features of the ISA-44-2-OD
Audio Alarm
Meters
( 3 places)
Operation Switch
Switch Indicator
Visual Alarms
(6 Places)
Oxygen Gain