Vaisala DMT340 - Manual (Page 139)

Chapter 4 _________________________________________________________________ Operation
VAISALA _______________________________________________________________________ 137
Manual AutoCal
To check that AutoCal has taken place for obtaining the most accurate
measurement in a very dry environment, you can perform Autocal
manually before measuring as follows:
1. Open the Main Menu by pressing any of the arrow buttons.
2. Select Measuring
, press the ►arrow button.
3. Select Manual AutoCal
, press the ►arrow button.
4. Press START to start AutoCal. If the AutoCal conditions are not
fulfilled, a note appears on the display informing that the
calibration cannot be made.
0706-014
Figure 72 Following AutoCal on the Display
5. Press EXIT to return to the basic display.
You can also perfom Autocal manually by using the pressure set and
check buttons on the motherboard. By pressing both buttons
simultaneously, Autocal is performed, see Figure 66 on page 107.
Sensor Purge
Sensor Purge is a feature available for the DMT340 DRYCAP®
M-sensor. The Purge should be carried out to achieve the shortest
response times and the best long-term stability.
Sensor Purge is an automatic procedure, in which the sensor is dried.
Thus, the sensor will response very fast when installing the probe from
an ambient to a dry gas. This will also ensure together with AutoCal the
best measurement accuracy and long-term stability.
As a default, the interval Purge and power-up Purge are turned on
automatically in DMT340. It is recommended not to turn them off. The
sensor Purge can also be started manually. If enabled, power-up Purge
will start always about 10 seconds after reset. If the power is
continuously turned on in DMT340, the automatic sensor Purge will be
performed at an interval of 24 hours.