Owner's manual

User's Guide _______________________________________________________________________
132 __________________________________________________________________ M210762EN-G
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 64 Following AutoCal on the Display
5. Press EXIT to return to the basic display.
You can also activate Manual AutoCal by pressing both AUTOCAL
buttons on the transmitter motherboard. These are the same buttons as the
pressure set buttons, but when pressed simultaneously, they will start the
AutoCal procedure. See Figure 58 on page 101 for location of the
AUTOCAL/pressure set buttons.
If the AutoCal conditions are not fulfilled, a note appears on the display
informing that the calibration cannot be made.
Sensor Purge
Sensor Purge is available for DMT345 and DMT346. 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 respond very fast when installing the probe from an
ambient to a dry gas. Sensor Purge also corrects the possible gain drift
caused by some chemicals, thus ensuring 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 DMT345 and DMT346. It is recommended not to turn
them off. The automatic 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 the transmitter, the automatic
sensor Purge will be performed at an interval of 24 hours.
A sensor purge should be performed always before calibration (see the
calibration instructions) or when there is a reason to believe that a sensor
has become exposed to an interfering chemical.