Resetable Audio-Visual Alarm Option (Nfpa Compliant) - Teledyne 8800A Operating Instructions Manual

8800 Series Trace Moisture Analyzer Instruction Manual
four times will display "1234". Pressing and holding the "MODE" button, will display "
LOC", indicating that the instrument is now unlocked. It may be locked without the password,
same as any other instrument.
Note: To avoid unauthorized changes, it is imperative that instrument is returned into the locked
mode.
11. Sensor Cable Compensation: As noted in other paragraphs this instrument measures the
impedance of the sensor (in the form of attenuation in decibels) from which it computes the
dewpoint. At very low dewpoints the sensor capacitance is small enough to be in the same
order of magnitude as a long coaxial cable. Thus the measurement circuit must be compen-
sated for the impedance of the sensor cable. Instruments which are delivered with a cable
are already compensated at the factory and should not be compensated again, however if
a new cable is connected, the following procedure should be used for compensation (also refer
to the Set-Up State flow diagram in Appendix A):
a. Disconnect the sensor from the cable by unplugging the BNC connector, keep the cable
connected to the instrument.
b. Prepare a means by which the BNC connector at the end of the cable could be reliably
shorted (using a jumper clip etc.), do not attempt to short at the instrument screw terminals as
this approach will not account for the cable resistance.
c. Go to the CNF/CBL/OPN (Confirm Cable Open) mode.
d. Leave the BNC connector open and press the UP key. The instrument will show OPN and
beep for a few seconds. Then it will show CNF/CBL/SHR (Confirm Cable Short).
e. Short the BNC connector and press the UP key, the unit will show SHR and beep for a few
seconds. Then it will show CNF/CBL/OPN again.
f. Leave the BNC connector open again and press the UP button. The instrument will show
OPN and beep for a few seconds. Then it will show END
The compensation data will be retained even if power is turned off.

3.5 Resetable Audio-Visual Alarm Option (NFPA compliant)

When the instrument is ordered with an Audio-Visual Alarm option, it is provided in the 8800B
enclosure, outfitted with two front panel momentary push buttons in NEMA sealed rubber boots.
The instrument complies with the recommendations of NFPA 99, 1996 edition.
• The alarm set point is programmed on a third alarm, hence the HI and LO alarm relays are free
to be used for additional purposes The third alarm is properly configured to 39°F at the fac-
tory, but when necessary may be modified by the user. Refer to the notes following HI & LO
Alarms in the Flow Diagram of Operating State User Interface in appendix A.
• The visual indicator is the display backlight. When there is no alarm condition the LCD dis-
play is not backlit but can still be easily and clearly read (in an extremely dark room the back-
light may be momentarily turned on by pressing the TEST button). However as long as an
alarm condition exists the LCD will be backlit in red. This lit-up front window of the instru-
ment is the visual indicator.
• This configuration is also equipped with a NEMA sealed audio indicator (>80dB @ 3ft)
mounted in the instrument enclosure. It is activated when an alarm condition occurs, it may be
disabled by momentarily pressing the RESET button on the front panel. When the alarm con-
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