Biosystems PhD Ultra Reference Manual - page 47
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reading “Too Low” or “Too High” for One-Button
Auto-Calibration fresh air adjustment.
Once the new sensor has been fresh-air calibrated
using the “manual” calibration procedure, it will then
be possible to do subsequent fresh air and span
calibrations by using the mode button and One-
Button Auto-Calibration procedures.
Note: The first fresh air calibration adjustment
after installation of a new sensor should be
done using the “manual” calibration procedure
as discussed in section 3.5 of this manual.
.
Figure 5.1.1. PhD Ultra sensor compartment cover
and sensors
5.2 Troubleshooting
There are a few troubleshooting and repair
procedures that can be done in the field.
5.2.1 Re-booting the microprocessor
software
Occasionally it may be necessary to re-boot or "cold
start" the PhD Ultra microprocessor software.
Disconnecting the battery, static discharge, or use of
keypad push-buttons in unauthorized combinations
may occasionally cause the microprocessor to
lockup or "crash". In this event it may be necessary
re-boot the microprocessor before the PhD Ultra can
be turned back on and put back into normal
operation.
The most significant symptom of a microprocessor
lock-up is the inability to turn the instrument back on
in the normal manner. The inability to turn the
instrument on may also result from a dead battery.
Make sure the NiCad battery is recharged, or the
alkaline batteries are replaced before attempting
to re-boot.
To re-boot the microprocessor:
(1) Remove the snap-in battery pack. (Make sure
to pull the battery pack completely free from the
instrument.)
(2) Replace the battery pack.
(3) If the re-boot procedure has been successful,
the instrument should resume normal operation.
If the re-boot is unsuccessful and the instrument is a
NiCad model, try the procedure again while the
instrument is connected to a 110 VAC power source
through the battery charger.
The PhD Ultra must be located
in a non-hazardous location during the charging
cycle. Charging the PhD Ultra in a hazardous
location may impair intrinsic safety.
The PhD Ultra is Classified by Underwriters
Laboratories, Inc., the Canadian Standards
Association, and European Community
Certification as to Intrinsic Safety for use in
Hazardous Locations Class I, Groups A, B, C,
and D. This classification is void while the PhD
Ultra is operated while connected to the battery
charger in hazardous areas.
5.2.2 Specific problems
5.2.2.1 Problem: Unit will not turn on
Possible causes:
Battery discharged, microprocessor / software
malfunction.
Solution(s):
Take the instrument to a non-hazardous
location. If equipped with an alkaline battery
pack replace the batteries and attempt to turn
on. If equipped with a rechargeable NiCad
battery pack, plug the PhD Ultra into the battery
charger for several minutes. With the
instrument still connected to the battery charger,
attempt to turn the detector on. If this works,
the battery needs to be recharged or replaced.
If the instrument still fails to turn on, re-boot the
microprocessor using the procedures discussed
in Section 5.2.1. If the instrument still fails to
turn on, return to factory for repair.
5.2.2.2 Problem: Unit will not turn off
Possible causes:
Software malfunction, low or bad battery, faulty
on / off mode switch.
Solution(s):
Hold mode button down for thirty seconds. This
should turn the instrument off. Take the
instrument to a non-hazardous location. If
equipped with an alkaline battery pack replace
the batteries and attempt to turn the instrument
back on. If equipped with a NiCad battery pack
plug the PhD Ultra into the battery charger for
several minutes. With the instrument still
connected to the battery charger, attempt to turn
the detector on. If this works, the battery needs
to be recharged or replaced. If the instrument
still fails to turn on, re-boot the microprocessor