HF scientific Oil Content Bilge Alarm - Manual (Page 7)

Bilge Alarm (02/02)
Rev. 1.3
of 5 amps at 120VAC or 28 VDC resistive.
There are two sets of contacts which may be used to
operate valves, sound alarms, etc. These are wired as
follows refer to Figure #3 and #4. Note that the relay is
de-energized in the Alarm condition.
TB3 Set #1 Terminal #17 - Closed in the Alarm
Condition
Terminal #18 - Common
Terminal #19 - Open in the Alarm
Condition
TB3 Set #2 Terminal #20 - Closed in the Alarm
Condition
Terminal #21 - Common
Terminal #22 - Open in the Alarm
Condition
VI. START-UP
1. Turn on the Power Switch located on the Indicating/
Control Module.
2. Allow the instrument to warm-up for
approximately 30 minutes for stabilization. It is
recommended that the power to the instrument be
left on continuously except when servicing is
required.
3. Run clean oil-free water through the Sensing
Module.
4. Adjust the Zero Pot in the Indicating/Control
Module (Item B, Figure #6) to cause Digital
Display to indicate 00 PPM. NOTE: Negative
readings on the Digital Display are indicated by a
negative sign lighting up to the left of the Display
Digits. When making adjustments do not
over-adjust to negative values.
VII. CALIBRATION
The instrument has been factory calibrated in PPM.
However, if it is desired to check calibration, the
following procedure should be followed:
1. Run clean oil-free water through the Sensing
Module and adjust “Zero” control.
2. Using an In-Line Calibration Holder, HF Part
No. 20098, place a suitable calibration standard,
equivalent to a known value of oil in water, in the
Sensor.
3. When conditions have stabilized, observe
Recorder Output reading; it should read 10 Volts
DC for 100 PPM and any proportional linear
value between zero and 10 volts for lower values
(see example below). Recorder output is obtained
across terminals 10 (neg.) and 11 (pos.) in the
Indicating/Control Module, (Refer to Figure
#4).
EXAMPLES:
PPM (Oil in Water) Recorder Output Reading
100 PPM 10 Volts
15 PPM 1.5 Volts
4. Calibrate the Recorder Output to correct value
by adjusting the Trim Pot marked REC on the
Amplifier P.C. Board, (Refer to Item D, Figure
#5).
5. Adjust the Trim Pot marked DVM, on the same
P.C. Board, to cause the Digital Display to read
the correct value in PPM.
NOTE: 1. Whenever the value of the oil free water
changes, it can be “Calibrated Out” by simply
running a sample of the oil free water through the
Sensing Module and adjusting the “ZERO” Pot
in the Indicating/Control Module (Item B, Figure
#6) to obtain a reading of “00” on the Digital
Display.
2.
Calibration should be checked after
components have been replaced, i.e., P.C. Board,
or Lamp, etc.
3.
Whenever the instrument is re-calibrated a
new “Cal Check” number should be obtained
and recorded. See “Calibration Check” and follow
steps 1 through 4.
VIII. CALIBRATION CHECK
This is a procedure used to check that the electronic
function is still within the limits set by the Calibration
Check Number.
1. Open the Indicating/Control Module.
2. Activate the CAL Check Switch (Item F, Figure
5, Spring Return) and note reading.
3. With the Cal Check Switch returned to its normal
position and note reading.
4. Subtract the reading obtained in Step #3 above
from that obtained in Step #2.
5. Compare the value obtained, which is the current
Cal Check value, to the Cal Check number
supplied with the instrument, which is affixed to
the Indicating/Control Module Chassis. Should
this current value vary by more than three (3)
units from the original value, then the instrument
should be re-calibrated.
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