
Model 400E Ozone Analyzer
Instruction Manual
CALIBRATION PROCEDURES
P/N 04316 Rev: B
175
7.4.2.
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 6.8.2.
When the contacts are closed for at least 5 seconds, the instrument 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 7.6) feature and the AutoCal attribute “
CALIBRATE”
is enabled, the M400E
will not re-calibrate the analyzer UNTIL when 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.