biosystems PhD Lite User Manual

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Figure 2.5.3. PhD Lite sample probe assembly
2.5.3.1 Changing sample probe filters
The threaded sample probe handle is unscrewed (as
shown in Figure 2.5.3.) to provide access to the filters.
The particulate filter is held in place by means of a clear
filter cup. To replace the particulate filter, remove the
old filter and cup, insert a new filter into the cup, and
slide the cup back into place in the probe handle. The
hydrophobic barrier filter fits into a socket in the rear
section of the probe handle. (The narrow end of the
hydrophobic barrier filter is inserted towards the rear of
the handle.)
2.5.3.2 Changing sample probe tubes
The standard 11.5” long butyrate probe tube is held in
place by means of a hex-nut compression fitting and
compression sleeve. The standard probe tube is
designed to be easily interchangeable with other custom
length sections of 1/4” OD tubing, or probe tubes made
of other materials (such as stainless steel).
Probe tubes are exchanged by loosening the hex-nut
compression fitting, removing the old tube, sliding the
compression sleeve into place around the new tube,
inserting the new tube into the probe handle, then
replacing and tightening the hex-nut.
Note: The sample probe must be checked for
leakage (as discussed in Section 2.5.1.) whenever
filters or probe tubes are exchanged or replaced
before being put back into service.
2.6 Biosystems EEPROM equipped “Smart
Sensors”
Each sensor installed in a PhD Lite detector is equipped
with its own non-volatile memory storage device or
“EEPROM”. The contents of the sensor’s memory
device are designed to be read and updated directly by
the PhD Lite. The fact that each sensor is capable of
remembering and communicating important information
about itself to the instrument allows for a number of
important PhD Lite operating benefits.
2.6.1 Identification of type of sensor by
instrument
Sensors installed in the PhD Lite automatically identify
themselves to the instrument microprocessor. The PhD
Lite automatically displays the recognized sensors on
the liquid crystal display (LCD) and assigns the correct
alarm settings.
2.6.2 Other information stored with the sensor
EEPROM
The PhD Lite automatically uploads the sensor serial
number, the most recent calibration settings,
temperature compensation curves, and current alarm
settings whenever the instrument is turned on,
whenever a change is made during operation, and
whenever the instrument is turned off.
If a sensor is changed or replaced the PhD Lite
recognizes that a change has occurred, displays a
“Needs Cal” message the next time the instrument is
turned back on, and identifies the affected sensors.
Even if the change is only to replace one sensor with
another of the same kind, the PhD Lite will still note the
change in serial numbers of the sensors installed, and
display the “Needs Cal” message.
The accuracy of the PhD Lite
should be checked periodically with known
concentration calibration gas. Failure to check
accuracy can lead to inaccurate and potentially
dangerous readings. (The Canadian Standards
Association (CSA) requires an accuracy check
using known concentration calibration gas prior to
each day’s use.)
The accuracy of sensors
identified as “Needing Calibration” must be verified
by exposure to known concentration calibration gas
before the PhD Lite is put back into service. Failure
to do so may result in inaccurate and potentially
dangerous readings.
2.6.3 Sensor removal and replacement
Note: The PhD Lite must be turned off to replace
sensors.
1. Remove the three philips screws and take off the
sensor cover from the front of the instrument.

biosystems PhD Lite Specifications

General

Brand	biosystems
Model	PhD Lite
Category	Security Sensors
Language	English