Operation 4
IR7000
42
Teledyne Analytical Instruments., - Rev. 3
4.
C
AL
T
RACK OR
H
OLD
The TRACK/HOLD submenu selection determines how the
display and output signal behave during a calibration. If
TRACK is selected, the output signal and display will change
with the measured value of the gas during calibration. If HOLD
is selected, the output signal and display will remain fixed at
the last measurement prior to the calibration.
•
Select Cal TRACK or HOLD. Press the MODE button
repeatedly until you reach the FILTER submenu. Press
and
hold
the MODE button one more time to lock onto
the CAL=TRACK/HOLD submenu. Initially, the
default setting of HOLD is set and displayed on the
screen. Use the UP arrow to toggle between TRACK
and HOLD. Releasing the MODE button enters the
selection displayed on the screen.
NOTE:
If the instrument is set to CAL = HOLD, there will be no change in
display or output of the calibration value, it will hold on the last
measured value before the calibration command was given. At the
end of the calibration event, there will be another delay in output
equal to the CAL DELAY period while the gas concentration in the
sample cell changes from pure calibration gas to actual sample gas. If
the calibration has changed since the last calibration, there will be a
jump in the reading as the new calibration takes effect. See Figure 4-
3.
If the instrument is set to CAL = TRACK, the display and output will
change as the gas concentration changes. At the end of the
calibration event, there will NOT be a another delay in output equal to
the CAL DELAY period. The display and output will show the
changing gas composition as the cell adjusts itself from calibration
gas to actual sample. If the calibration has changed since the last
calibration, jump in the reading as the new calibration takes effect.
See Figure 4-4.