Servomex NanoTrace DF-760E, Инструкция по эксплуатации

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User Interface DF-760E 53
Figure 26: Moisture AutoZero Screen
NOTE: If oxygen is included in the background gas calculation, see page 103, the on-
board zero gas purifier is automatically prevented from being used. As a result an
adjustment of the moisture zero, must be done manually and the zero gas must be supplied
from the outside through the sample inlet.
The process measurement mode can be restored at anytime during the calibration process
by pressing
ESC
or it will be automatically restored at the end of the AutoZero process.
Before the AutoZero process can be started various criteria must be set using the AutoZero
Setup screen Figure 27. See page 54 for additional information.
After selecting “
Do an AutoZero
” from Figure 24 a screen similar to Figure 26 will
appear. Throughout the zero process the screen displays the current moisture reading as
well as the valve status and selected zero criteria. If a Pre-Zero purge time has been set in
the AutoZero Setup screen, then the zero purifier will be valved in and the gas will flow
through the purifier to purge the plumbing for that amount of time. Once the pre-purge is
complete, the twenty minute autozero cycle begins. During this twenty minute cycle, the
analyzer applies stability criteria. If after twenty minutes the moisture reading has
acceptable stability the analyzer automatically accepts the reading, updates the
Zero
Reference
, and returns to the Data Display Screen. If the reading is not stable, the
analyzer continues the stability monitoring until the criteria has been met or until the cycle
timer expires. In the latter case, the analyzer returns to operation on sample gas with no
adjustment to the zero calibration and reports a failed zero calibration. See the section on
AutoZero Setup below for a description of the
Cycle Timeout function. The Zero Ref in
the Check/Adjust Zero screen may change as a result of this process. Pressing ESC during
the calibration process will abort the action. The user may also restore the factory
calibration from the Check/Adjust Zero screen.
A relay is available on the Moisture Analog Output Setup Screen (see page 66) to signal
that a zero calibration is taking place. Also, the analog output signal can either be frozen or
allowed to update during the calibration process.