Det-Tronics PW9200x Pathwatch IR Gas Detection System - Manual (Page 8)

Hi
This position sets the instrument for the highest sensi-
tivity available. PW9200 instruments are factory set
and calibrated at HI sensitivity.
Mid
This position decreases the sensitivity of the instru-
ment by a factor of 3.
Lo
This position decreases the sensitivity of the instru-
ment by a factor of 10.
HC ALARM
Adjust
The HC ALARM Adjustment potentiometer is used to
set the threshold at which the RATIO voltage ener-
gizes the hydrocarbon alarm relay. The HC ALARM is
adjustable from 10% full scale to 100% full scale.
Setpoint (grey)
The HC ALARM Set Point test jack is used to access
the HC alarm threshold setting.
OUTPUT
The OUTPUT test jacks permit access to the NUMER-
ATOR, DENOMINATOR and RATIO outputs:
Ratio (brown)
RATIO output (ratio of the two IR beams): 0 to 10
volts.
Denom (red)
DENOMINATOR output (intensity of the HC beam): 0
to 600 mv.
Num (green)
NUMERATOR output (intensity of the reference
beam): 0 to 600 mv.
SIG GND (green)
The SIG GND test jack permits access to signal
ground.
OUT OPT (violet)
The OUT OPT test jack permits access to the optional
RATIO output (used only with the options P.C. board).
FUSE
The power line fuse has been located on the front
panel for accessibility.
OUTPUT SELECT SWITCH
This switch is used to select the type of RATIO output
that is available at the junction box:
O - Optional output mode
This position is available for optional processing data
output.
V - Voltage output mode
This position sets the RATIO output for 0 to 10 vdc.
MA - Milliamp output mode
This position sets the RATIO output for 4 to 20 ma, if
this option has been installed.
INSTALLATION
INSPECTION
Since the instrument could be subjected to shock or
vibration during shipping, an inspection of the con-
nections and filterwheel is recommended.
Prior to the initial setup of the instrument, open the
housing (see “Access to Internal Components” proce-
dure) and check that the printed circuit board(s) are
securely held in the connector(s). If a board has
become dislodged, return it to the proper connector.
The synchronous demodulator board is on the right of
the filterwheel and the options board is on the left
(See Figure 3). Observe the location of the keys and
do not attempt to insert the printed circuit board(s)
backwards. Be certain that the board is firmly seated
in the connector and that both the top and bottom are
held by the card guides. Check that the ribbon con-
nectors on the AGC/TE cooler board and on the rear
panel board are fully engaged and that the latches
are locked. Rotate the filterwheel to check that it
spins freely. Check that the two receiver connectors
are securely engaged.
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