Teledyne API Model 401 O
3
Photometric Calibrator Instruction Manual, 01124, Rev. J1
3.3 Automatic Zero/Span (or Multipoint) Check
Automatic zero/span gas supply must be enabled in the setup mode. There are five parameters
that affect zero/span checking: the zero and span duration, the time of day for calibration, the
time shift, the zero and multipoint calibration switch, and the feedback mode. These are
described individually below.
To set the duration of the zero/span check, press the following sequence of buttons from the
STBY mode:
SETUP-EVNT-WAIT
. Enter the duration for the zero check and then press
ENTR
. Similarly enter the duration for the span check and then press enter. To shift the Z/S
check time backwards each day, select "-" and enter a number from 1 to 60. To disable shifting
of the check time (i.e. to Z/S check at the same time each day), enter a time shift of 0.
To enable automatic zero/span checking, press following sequence of
SETUP-EVNT-ASEQ
.
The CPU will display the current setting in the menu field above the first button. Press "OFF" in
order to disable automatic sequence, then press "ENTR". Likewise, select AZS for zero and span
(See Section 3.2 or 3.4 How To preset O
3
concentration which is specified in O
3
GN or ASEQ of
main menu.), AZ2S for zero and two span points, (25% AND 100% of preset O
3
concentration)
and AZ5S for zero and five span multipoint (20%, 40%, 60%, 80%, and 100% of preset O
3
concentration) sequence.
O
3
generator has three different modes of lamp feedback control. Press sequence of
SETUP-
MISC-O3-GEN-MODE
to select constant (CNST) lamp current control, reference (REF)
detector feedback control, or bench (BNCH) feedback lamp control.
Bench feedback is
recommended to generate fast response, stable, and accurate O
3
concentration in which the
optical bench is used as a feedback detector to control O
3
generating lamp.
3.4 Manual Zero/Span (or Multi-Point) Check
Manual zero/span (or multi-point) is activated by pressing "ASEQ" button from the main menu
display. Then enter the password, specify full scale concentration between 50ppb - 1000ppb
which would be 100% of span concentration, and press ENTER to select. This feature is
identical to the automatic zero/span check sequence except it is activated manually. This ASEQ
entry is not shown on display unless it is programmed. In order to enable this feature, automatic
zero/span check parameters must be preset (See Section 3.3 or 4.2). While multipoint calibration
is in progress pressing "STBY" will terminate "ASEQ".
3-2
