Teledyne 8800A Operating Instructions Manual page 34

b. Use the UP or DOWN buttons to modify the cal-adjust value as necessary.
c. Press the MODE button to go to the next mode, this will save the new cal-adjust value, and
it will be retained even if power is turned off.
6. Analog Output Span selection 4/20 mA or 0/24 mA: By pushing the UP or DOWN buttons,
the user may select the desired span of the analog output.
7. Testing the analog output: By pushing the UP, DOWN, or Pressure Correct buttons, the user
forces the analog output to its high, low and mid-range values, respectively. This facilitates
the hook-up and testing of the user's monitoring equipment.
8&9Output range setting: These modes are used to set dewpoints corresponding to the low and/
or high end of the Analog Output. The factory default values are: low end at -100°C, and high
end at +20°C. For detailed discussion of the necessary considerations when choosing the ana-
log output range, refer to appendix J.
10. Lock/Unlock the instrument with optional SECURED password protection
The Lock/Unlock feature of the instrument allows the owner to block access to parameter set-
tings, protecting the instrument from unauthorized or inadvertent changes. Attempting to
change settings while the instrument is locked will display LOC and beep.
• When in the Lock/Unlock Mode and the instrument is locked the display will show "
The instrument may be unlocked by pressing the "UP" button. If "SEC" is displayed, refer to
the Secured Password Protection section below.
• When the instrument is unlocked the display will show "
that the display is alternately showing UN and LOC, this is necessitated by the 3.5 digit limita-
tion of the display. Pressing the "DOWN" button will lock the instrument.
• Pressing and holding either the "UP" or "DOWN" buttons, will save the locked or unlocked
setting depending on the button, and reset the instrument. This feature is useful in situations
where it is difficult or undesirable to power off the instrument.
• Pressing the MODE button will navigate to the Sensor Cable Compensation mode.
Secured Password Protection
Instruments may be specially ordered with password protection. To unlock the instrument the user
must supply a password, which consists of a number in the range of -1999 to 1999 (approximately
4000 unique passwords). Instruments that require a password, will display "SEC" (secured) when
the user attempts to unlock by pressing the "UP" button. After approximately 1 to 2 seconds the
instrument will display "000", with the first digit flashing. The flashing denotes the cursor posi-
tion, which means that the "UP" and "DOWN" buttons will increment or decrement this digit
respectively. Pressing the "MODE" button will move the cursor (flashing digit) to the right. Press-
ing and holding the "MODE" button will signal the instrument to read the password and if correct
to unlock the instrument. As discussed above an unlocked instrument will display "
The user may enter the assigned password by pressing the UP, DOWN and MODE buttons. The
first digit is unique in that it consists of 1½ digits in the range of -19 to 19, this allows entering the
full range of assignable numbers.
An example is used to illustrate the unlocking of a password-protected instrument. Suppose the
password is 1234. After an attempt to unlock, the user will see "SEC" followed by "000", with the
first 0 flashing. Pressing the "UP" button twelve times will display "1200" (overshooting a num-
ber can be corrected by reversing the use of the UP and DOWN keys), with the "12" flashing.
Pressing the "MODE" button will flash the next "0". Pressing the "UP" button three times will
display "1230". Pressing the "MODE" button will flash the last "0". Pressing the "UP" button
UN/LOC". The slash (/) denotes
SET
27
Section 3: Instrument
LOC".
SET
UN/LOC".
SET