Analytical Industries GPR-28 Oxygen Analyzer - Manual (Page 21)

Advanced Instruments Inc.
21
Establishing Power to the Electronics
Establish power to the electronics by connecting the power cable to an appropriate source of AC power. The electronics are
rated for a universal power input of 100-230 +/-10% VAC 50-60 Hz, unless the analyzer is equipped with the optional
temperature controlled heater system. Ensure the voltage provided is appropriate for the heater.
The LCD display along with range LED on the side of the display should light up when power is applied to the analyzer.
Assuming the analyzer has been installed as directed above, the reading displayed when the analyzer is turned on reflects the
oxygen value under static condition (i.e. the axiom that all valves leak) indicating the integrity of the internal sample system or
the equilibrium point of oxygen diffusing into the sample system and oxygen consumed by the sensor.
Display Mode
The DISPLAY SELECT slide switch is located inside the front door on the A-1107 PCB Assembly Main/Display has been factory
set to the O2 position, refer to the illustration above under the Mounting the Analyzer section. Advance this switch to change or
one of the available DISPLAY modes:
¾ OXYGEN to display the oxygen reading
¾ ALARM 1 set point
¾ ALARM 2 set point
Setting Alarm Values
The analyzer is equipped with one high and one low fully adjustable alarms. When activated the alarms trigger SPDT Form C
non-latching relays @ 5A, 30VDC or 240VAC resistive. The alarms are fully adjustable by the two potentiometers accessible
from the auxiliary panel on the inside of the door. Optionally, alarm control actuators can be mounted externally as illustrated in
the Mounting the Analyzer section above.
The alarm setpoint represents a value. When the oxygen reading exceeds ALARM 2 (high alarm) or falls below ALARM 1 (low
alarm) the alarm setpoint, the relay is activated and the corresponding LED indicator located on the front door is turned on.
To prevent chattering of the relays, a 2% hysteresis is added to the alarm setpoint. This means that the alarm will remain active
until the oxygen reading has fallen 2% below the alarm setpoint (high alarm) or risen 2% above the alarm setpoint (low alarm)
after the alarm was activated.