Trace Oxygen Analyzer Operation 4
4-5
Teledyne Analytical Instruments
4.3 The AUTO-CAL Function
When proper automatic valving is connected (see chapter 3, installa-
tion), the Analyzer can cycle itself through a sequence of steps that automati-
cally zero and span the instrument.
Note: If you require highly accurate AUTO-CAL timing, use external
AUTO-CAL control where possible. The internal clock in the
Model 3020T is accurate to 2-3 %. Accordingly, internally
scheduled calibrations can vary 2-3 % per day.
To setup an AUTO-CAL cycle:
Scroll to AUTO-CAL, and ENTER. A new screen for Span/Zero set
appears.
Span OFF Nxt: 0d 0h
Zero OFF Nxt: 0d 0h
If SPAN (or ZERO) is not between the arrows, scroll with DOWN/UP
control to SPAN (or ZERO), then ENTER. (You won’t be able to set OFF to
ON if a zero interval is entered.) A Span Every ... (or Zero Every ...)
screen appears.
Span Every 0 d
Start 0 h from now
Use DOWN/UP control to set an interval value, and ENTER. Then use
DOWN/UP to set a start-time value, and ENTER.
To turn ON the Span and/or Zero cycles (to activate AUTO-CAL):
Scroll to AutoCal, and ENTER it again.
Span OFF Nxt: 0d 0h
Zero OFF Nxt: 0d 0h
When the Span/Zero values screen appears, use the scroll DOWN to
blink the OFF/ON field of the SPAN (or ZERO) function. Use DOWN/UP
to set the OFF/ON field to ON. You can now turn these fields

ON

because
there is a nonzero span interval defined.
4.4 The PWD (Password) Function
Security can be established by choosing a 5 digit password from the
standard ASCII character set. If you decide NOT to employ password
security, use the default password TETAI. This password will be displayed
automatically by the microprocessor. The operator just ENTERs it to be
allowed total access to the instrument’s features.