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Chapter 4 PhD Ultra Advanced
Functions
4.1
PhD Ultra advanced features
overview
PhD Ultra microprocessor circuitry makes a number
of advanced features and capabilities possible. The
four buttons located on the instrument keypad may
be used to change alarm set-points, to change the
kind or concentration of calibration gas used during
auto-span calibration procedures, to assign an
instrument ID number, or to make use of other PhD
Ultra optional setup choices.
Use of keypad buttons to setup or reprogram
the PhD Ultra is reserved for authorized
personnel.
These techniques frequently require several buttons
to be pressed and held at the same time.
Caution:
Do not press any combination of
buttons other than those listed below. Doing so
may result in the loss of stored data in the PhD
Ultra’s datalogger memory.
4.2
Setting alarm levels
PhD Ultra gas alarms are user adjustable and may
be set anywhere within the range of the sensor
channel. When an alarm set point is exceeded a
loud audible alarm sounds, and an individual bright
red LED alarm light for each affected sensor blinks.
PhD Ultra alarms are normally self-resetting.
Alarms cease as soon as readings drop below the
alarm set point. It is possible, if desired, to set PhD
Ultra alarms so that they "latch". When an alarm
occurs with the alarms latched the visual and
audible alarms will continue even after the
atmospheric hazard has cleared. The instrument
must be manually reset by pressing the mode
button. Pressing the mode button silences the
alarms and returns the instrument to normal
operation.
Procedures for latching PhD Ultra alarms are
given in Section 4.3.
4.2.1 Alarm adjustment sequence
Note: Factory default settings can be restored at
any time during normal operation by using the
procedures discussed in Section 4.2.2.
In many cases it is possible to comply with OSHA
guidelines while using higher alarm points than
those used by Biosystems. It is important to note
that the default alarm point settings in the PhD Ultra
are very conservative in order to maximize worker
safety.
PhD Ultra default alarm setting are listed in
Section 5 of Appendix B.
To enter the “Alarm Adjust” mode:
(1) Make sure the instrument is turned off.
(2) Slide the belt clip towards the rear of the
instrument to expose the four buttons on the
instrument keypad.
(3) While holding down the "Alarm" button, press
the mode button to turn the PhD Ultra back on.
The software version screen will be shown
briefly. The screen will then show a number of
screens to indicate that the instrument is loading
sensor and instrument data.
Do not release the “Alarm” button until the
"Adjust Alarms" message appears on the
display screen.
This will be followed by a screen showing the
first alarm point to be adjusted, which is typically
the oxygen sensor alarm.
Note: Pressing the mode button at any time
cancels the “Alarm Adjust” mode. The
instrument will display a screen indicating
“Adjust Alarms, Unchanged”. This screen
will be followed by another announcing
“Begin Shut Down, Please Wait”. The
instrument will then turn itself off.
(5) Press the “CAL” button to advance the display
to the next available alarm adjustment option.
(6) When the desired alarm adjustment has been
reached, use the "+" and "-" keys to raise or
lower the alarm setting.
(7) When all alarm adjustments have been
completed, press and hold the "Cal" button down
until the screen advises you to “Release Button”.
An information screen will indicate when alarm
adjustment is complete. This screen will be
followed by another announcing “Begin Shut Down,
Please Wait”. The instrument will then turn itself
off.
