Analytical Industries GPR-35 Oxygen Analyzer - Manual (Page 14)

Advanced Instruments Inc.
14
Gas Connections
The GPR-35 is designed for in-situ ambient or area monitoring and has no sample system because the sensor is intended to be
exposed directly to the surrounding ambient atmosphere which it is sampling and to operate at atmospheric pressure, however,
slightly positive pressure has minimal effect on accuracy.
A certified span gas is recommended for
calibration purposes. A Calibration Flow
Adapter (P/N A-2344 see illustrations) is
supplied with the GPR-35 and provides a
barbed hose connection for piping the
calibration gas (see positive pressure see
below) to the sensor, an o-ring seal to
isolate the sensor from the atmosphere
being monitored and outlet to vent the
calibration gas.
Further, applications situations may dictate
that the sample be transported from a
semi-sealed area to a safe area where the
analyzer is located. In these cases the analyzer can be readily adapted to include optional pumps, tubing and connection
fittings.
Electrical Connections
The electronics are rated for a universal power input of 100-230 +/-10% VAC 50-60 Hz. Connect one end of the power cable to
the analyzer’s terminals but do not connect the other end to a source of power.
Danger: To avoid electric shock exercise extreme caution when servicing the analyzer. Disconnect the AC power source before
removing the protective plexiglas panel that covers the terminal block. If the AC power source is connected to the terminal
block, touching any terminal connections where AC power is present such as transformer pins and AC connector on the PCB
Assembly would result in an electric shock. Note: There is no AC power present on the circuit board assemblies found on the
backside of the analyzer’s front cover.
In the event the AC power is interrupted it is backed up by a standby rechargeable lead acid battery that provides enough
power to operate the unit continuously for 8 hours in the alarm mode. Caution:
Continuous use of the analyzer beyond the
low battery warning may result in permanent damage to the battery.
The analyzer has been fully tested, the dual oxygen alarms set according to OSHA or optional customer specifications, the
battery fully charged and the oxygen sensor installed prior to shipment. Without AC power the electronic circuit switches to the
standby battery power source. To avoid draining the battery during the transit period, if the analyzer is equipped with the
optional integral sampling pump, the BATTERY / PUMP switch has been placed in the OFF position for shipping.
As illustrated below the protective panel contains the wiring connections. Caution: Always replace the protective plexiglas
panel after servicing AND before establishing power to the analyzer electronics.