TM 5-6640-212-14
NOTE
(a) To impress an alarm-level triggering signal on
the alarm circuit, turn ZERO potentiometer adjustment
If FAIL light comes on during
screw slowly clockwise until alarm relay K2 energizes
adjustment operations, wait 45
and ALARM light goes on (circuit card extender circuitry
seconds after FAIL light goes out so
prevents operation of external alarm devices). A two-
that time delay circuit will not
second time delay occurs before light goes on and relay
interfere
with
continuing
operates after trigger signal begins.
adjustments.
(b) If ALARM light goes on at a meter per-cent
LEL reading lower or higher than desired, turn screw
(a) To impress a warning level triggering signal on
adjustment of ZERO potentiometer to' obtain a meter
the warning circuit, turn ZERO potentiometer adjustment
reading 2 or 3 percent below the desired point.
screw (R24 for CD800/830, R9, labeled Z1, for Channel
(c) Press RESET button to deenergize alarm
1 or R13, labeled Z2, for Channel 2 of CD802/832
relay.
systems) slowly clockwise until warning relay K1
(d)Turn
screw
adjustment
of ALARM
energizes and WARN light goes on (circuit card extender
potentiometer (R29 for CD800/830 Systems; R41
circuitry prevents operation of external warning devices).
labeled
"A"
for
CD802/832
Systems)
fully
A two-second time delay occurs before light goes on and
counterclockwise until alarm relay energizes and ALARM
relay operates after trigger signal begins.
light comes on (after two-second delay past trigger
(b) If WARN light goes on at meter percent LEL
point).
reading lower or higher than desired, turn screw
(e) Push and hold down RESET button and turn
adjustment of ZERO potentiometer to obtain a meter
ALARM potentiometer adjustment screw slowly
reading 2 to 3 percent below the desired point.
clockwise until ALARM light goes off (time delay circuit
(c) Press RESET button to deenergize warning
does not operate as light goes out and relay
relay.
deenergizes).
(d) Turn
screw
adjustment
of
WARN
(f) Turn screw adjustment of ZERO potentiometer
potentiometer (R26 for CD800/830 Systems: R48,
until ALARM light goes on, signifying an energized alarm
labeled
w,
for
CD802/832
Systems)
fully
relay. Note percent LEL meter reading at this point.
counterclockwise until warning relay K1 energizes and
(g) Repeat steps (b) through (e) for fine
WARN light comes on (after two-second delay past
adjustment or alarm relay trigger point.
trigger point).
(h) Return screw adjuster of ZERO potentiometer
(e) Push and hold down RESET button and turn
to setting that re-zeros indicating meter pointer after
WARN potentiometer slowly clockwise until WARN light
confirming that detector is sampling gas-free air.
goes off (time-delay circuit does not operate as light
(3) Test Adjustment. The TEST pushbutton, when
goes out and relay deenergizes).
depressed, closes a circuit to ground through one lead to
(f) Turn screw adjustment of ZERO potentiometer
differential amplifier U3, thus impressing a voltage
R24 until WARN light goes on, signifying an energized
equivalent to that which would appear on the lead if the
warning relay. Note percent LEL indication at this point.
detector were sensing a gas-air mixture of 100 percent
(g) Repeat steps (b) through (e) for fine ad-
LEL. Adjust test circuit to obtain a full-scale meter
justment of warning relay trigger point.
reading (100 percent LEL) as follows:
(h) Using ZERO control, rezero indicating meter
(a) Press TEST pushbutton and observe deflection
after confirming that detector is sampling gas-free air.
of meter pointer.
(2) Alarm Circuit Adjustment. Adjust alarm circuit
(b) If reading is less than full scale, or if pointer
to operate at the voltage level representing a specified
rapidly swings to a mechanical stop, turn screw adjuster
percent LEL gas-air mixture as follows:
of RANGE potentiometer R22 on control module printed
NOTE
circuit board (CD800X: located on narrow flange below
If FAIL light comes on during adjustment operations,
opening at left in-side circular window) to obtain a full-
wait 46 seconds after FAIL light goes out so that
scale meter reading with TEST pushbutton depressed.
time delay circuit will not interfere with continuing
adjustments.
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