12
correct buttons operate in the same manner as in the Sensor Pressure sub-state. Pressing
the ‘Mode’ button changes the unit back to View/Set Sensor Pressure sub-state, and so
forth. Note: The units leave the factory in the lock mode and must be unlocked before this
procedure can take place (see section 5.3 #7 to unlock). The factory default settings are:
14.7psi for both sensor and gas pressure and pressure correction disabled. When
Pressure correction is disabled all dewpoints are computed by assuming that both Sensor
and Gas Pressures are 14.7psi.
5.2.2 Viewing Temperature at the Sensor
In this mode the user can view the temperature at the sensor inside the sampling chamber,
signified by the flashing ‘TEMP’ legend on the lower left of the display. The available units
in which to view the temperature are °C and °F. The up and down buttons switch back and
forth between these units. Pressing the ‘Mode’ button changes to the Start Autocal Mode.
5.2.3 Start Autocal Mode
In this mode the user is prompted to confirm that Autocal should be initiated. This mode can be
skipped by pressing the ‘Mode’ button to go to the View Serial Number Mode or by cancelling with
the down or pressure correct buttons which displays the word
CAN
for 1/2 second and goes back to
the Viewing Dewpoint Mode. Autocal can be initiated by pressing the ‘up’ button. The unit will
check if the sensor is in the sampling chamber, if not it will prompt the user to pull the sensor out of
the desiccant by beeping and displaying alternately
PUL
and
OUT
. Pull the sensor actuator out,
when this message appears.
Since Autocal is a irreversible recalibration of the instrument there is one more beeping and visual
prompting with alternating
CNF
and
AC?
. The down and pressure correct buttons allow cancelling
the Autocal, while the up button confirms it. The unit starts taking measurements for 1 minute while
displaying alternately flashing
AC
. During this time the user should occasionally pump saturated air
using the calibration bulb into the sample chamber (see Autocal Instructions). An alternating
SEN
and
2LO
after one minute, accompanied by a beeping, indicates the sensor has a reading too low to
be from a saturated sensor. This error will cause Autocal to be cancelled. However, if the sensor
reading is within range of a saturated sensor, a new calibration is calculated (some numbers flash on
the display),
END
is displayed for 1 second, and the new calibration values are saved in EEPROM.
5.2.4 Viewing Serial Number Mode
In this mode the user can view the serial number of the sensor. The display shows the serial number
by alternately displaying
ESN
and the number. If the number is larger than 1999 then it is displayed
in 2 parts, first part is the thousands signified by the x10
3
legend in the upper right corner of the
display and the second part is the units.
For example serial number 12345 will be shown as:
ESN
12
x10
3
345
Pressing the ‘Mode’ button changes the unit to the Viewing Dewpoint Mode.
