14 of 66 Installation - 3654 Portable H2/N2 Analyzer
Operator Manual
ORBISPHERE
1.8.1 Power
The instrument is designed to work on battery power or an external power supply.
If battery power should drop, a [LO BAT] warning appears in the instrument LCD's top
left corner, and they should be replaced.
If using an external power supply, ensure that this is clean, otherwise it may result in
unstable measurements.
1.8.2 Check the Purge Gas Supply
It is critical that the TC sensor has a supply of purge gas before operating the system.
The TC sensor, when exposed to a liquid sample, could be damaged if the instrument
purge gas cylinder is empty. At the same time, it is also critical that the instrument has a
power supply to ensure the purge gas is supplied to the sensor on a regular basis. The
system purges the sensor for 4 seconds every 20 seconds during normal measurement
mode, and every 17 minutes during standby mode.
A small, pressurized cylinder at the bottom of the instrument supplies purge gas to the
sensor. The purge gas required is:
•N
2 purge for H2 measurements.
•CO
2 purge for N2 or H2 measurements.
Verify that the purge gas is flowing at more than four bubbles during the purge cycle, by
placing the purge gas exit tubing into water.
Note:
You must supply power constantly to the instrument, since it purges the sensor
continuously while power is on. When you put the instrument in standby, it still maintains
the purge gas supply to the sensor. Thus, make certain to supply battery or optional
external DC power constantly if the instrument is in standby and the sensor is exposed
to a sample. The batteries will provide about three weeks of power for purging while the
instrument is off.
1.8.3 Instrument Clock Setting
If you use the instrument to store measurements for downloading to a PC, you should
verify the date and time settings of the instrument's internal clock, as described in “Clock
Settings” on page 51.
1.8.4 Barometric Pressure Setting
The internal barometric pressure sensor has been factory calibrated but should be
verified on-site with a precision certified barometer, and corrected if necessary. For
instructions on how to do this, please refer to “Barometric Pressure Sensor Calibration”
on page 35.
1.8.5 Sensor Membrane
Check that the membrane has been installed correctly, and is flat, tight, and wrinkle free.