ENMET ISA-200-RAL (O) - Manual (Page 13)

ISA 200 RAL (O) ENMET Corporation
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4.4 Audio Defeat
With the alarms in the non-latching configuration, pressing the ALARM ACKN/AUDIO DEFEAT switch during an
alarm silences the audio alarm.
With an alarm in the latching configuration, pressing the ALARM ACKN/AUDIO DEFEAT switch during an alarm
silences the audio alarm and unlatches the associated relay(s).
4.5 Display
In clean air, the display is as shown in Figure 4, for the sensor(s) installed in the ISA-200 RAL(O). This position of
the display is termed the "operational display". As explained below, the display can be changed to furnish other
information by using the OPTION and SELECT switches.
Concentrations of CO are given in PPM (parts per million parts of air). Oxygen concentration is given in per cent by
volume. When sample flow is reduced below a limit, the display switches from "Flow: yes" to" Flow: no", or from
"Flow: y" to "Flow: n".
4.6 Operational Menu
The operational menu allows the user to:
§ View alarm set point concentration values
§ View alarm latching configurations
§ Enter the maintenance menu with the proper key.
The operational menu is accessed with the OPTION and SELECT switches. The operational menu flow chart is
shown in Figure 5,
§ The OPTION switch is indicated with a "O"
§ The select switch is indicated with a "S".
If the instrument is left at any location in the operational or maintenance menus, other than the operational display,
with no action taken for a period of 45 seconds, it returns to the operational display.
Figure 5: ISA-200 RAL(O) Operation Menu Flow Chart
4.7 Fault Indications
4.7.1 Low Flow Indication
A sensitive pressure switch is used to furnish a low flow indication. When the sample air pressure drops below
approximately 30 psig, the fault light and audio alarm are activated, and the display reads either "Flow: no" or "Flow:
n", depending upon the number of sensors installed in the instrument.
4.7.2 Other Fault Indications
Other fault indications are associated with sensor zero and calibration activities, and are described in the maintenance
section 5.0 of this manual.
Operational
Display
O
O
O O
O
S
S
S
S
S
%O2: 19.5 23.5
LATCH: no no
PPM CO: 10
LATCH: no
000 PPM 20.9%
FLOW :y
run Maintenance
Menu
view ALARMS
& LATCHES
To Key
No Function
No Function
No Function
O = Option Switch
S = Select Switch