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T400 Ozone Analyzer Operator’s Manual T400 Calibration Procedures
195
9.3.3.3. Use of Zero/Span Valve with Remote Contact Closure
Contact closures for controlling calibration and calibration checks are located on the rear
panel CONTROL IN connector. Instructions for setup and use of these contacts are
found in Section 3.3.1.6.
When the contacts are closed for at least 5 seconds, the instrum
ent switches into zero,
low span or high span mode and the internal zero/span valves will be automatically
switched to the appropriate configuration.
The remote calibration contact closures may be activated in any order.
It is recommended that contact closures remain closed for at least 10 minutes to
establish a reliable reading.
The instrument will stay in the selected mode for as long as the contacts remain
closed.
If contact closures are being used in conjunction with the analyzer’s AutoCal (see
Section 9.4) feature and the AutoCal attribute “CALI
BRATE” is enabled, the T400 will
not re-calibrate the analyzer until the contact is opened. At this point, the new
calibration values will be recorded before the instrument returns to SAMPLE mode.
If the AutoCal attribute “CALIBRATE” is disabled,
the instrument will return to
SAMPLE mode, leaving the instrument’s internal calibration variables unchanged.
9.4. AUTOMATIC ZERO/SPAN CAL/CHECK (AUTOCAL)
The AutoCal system allows unattended periodic operation of the ZERO/SPAN valve
options by using the T400’s internal time of day clock. AutoCal operates by executing
SEQUENCES programmed by the user to initiate the various calibration modes of the
analyzer and open and close valves appropriately. It is possible to program and run up
to three separate sequences (SEQ1, SEQ2 and SEQ3). Each sequence can operate in
one of three modes, or be disabled.
Table 9-1: AutoCal Modes
MODE NAME ACTION
DISABLED
Disables the Sequence.
ZERO
Causes the Sequence to perform a Zero calibration/check.
ZERO-LO
Causes the Sequence to perform a Zero and Low (Midpoint) Span
concentration calibration/check.
ZERO-HI
Causes the Sequence to perform a Zero and High Span concentration
calibration/check.
ZERO-LO-HI
Causes the Sequence to perform a Zero, Low (Midpoint) Span and High
Span concentration calibration/check.
LO
Causes the Sequence to perform a Low Span concentration
calibration/check only.
HI
Causes the Sequence to perform a High Span concentration
calibration/check only.
LO-HI
Causes the Sequence to perform a Low (Midpoint) Span and High Span
concentration calibration/check but no Zero Point calibration/check.
06870C DCN6332