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4 Operation Model 9700
TELEDYNE BROWN ENGINEERING
Analytical Instruments
4.1.5 Operational Calibration
After the equilibration period following the installation of any new
cell, or whenever it is desirable to recheck the calibration of the instru-
ment, use the following calibration procedure:
(1) Place the RANGE selector switch on the 0+25% Position.
(2) Rotate the selector valve so that calibration (or span) air is
flowing.Allow air to flow for 3 to 5 minutes.
(3) Unlock and adjust the SPAN control until the meter pointer is
in precise coincidence with the scale CAL mark (use the mirror
to eliminate parallax) and relock the SPAN control.
(4) Return the instrument to service by restoring sample flow and
selecting the range that provides the best possible resolution of
the sample oxygen .
(5) To prevent generating ambiguous alarms during calibration of
alarm equipped instruments, simply unlock and rotate the
setpoint dial (or dials) until the limits of travel in the NORMAL
(rather than ALARM) direction have been attained. After
sample flow has been reestablished and the proper scale of
analysis selected, the alarm point can be precisely reset by
simplre-dialing the setpoint.
(6) For converter-equipped instruments, the current output of the
converter always tracks the output of the measuring circuit
amplifier. No provision for interlocking the converter to a
particular range of analysis has been provided. If the current
output is being used to operate a pneumatic control device, the
customer will be required to provide whatever necessary
electrical or mechanical interlocks necessary to safeguard his
system against the signal changes that will occur during
calibration.