Issue/Rev. 0.2 (7/00)
Page 3
By placing a small amount of high frequency alternat-
ing current on the probe inner electrode, it is possible
to detect changes in the dielectric. Knowing the area
of the electrodes and the Dk of the oil, it is possible to
determine the capacitance of a probe when full of clean
oil or other hydrocarbons. Should the oil become con-
taminated with water, changes in the capacitance are
displayed as a percent contamination of the oil.
Specifications
Temperature
Unit: -4°F to 158°F ( -20°C to 70°C).
Process (Oil): 32°F to 160°F (0°C to 71°C).
Power
18 to 32 Vdc (24 Vdc nominal) at 250 mA maximum.
Range of Dielectric Constant (Dk)
1.7 to 5.0
Accuracy
Is defined as the amount of variance observed between
the 7300 reading and the water grindout of the oil flowing
through the probe.
Normal variances are:
±
.05
........................ From 0 to 5% water cut.
±
.1
........................ From 5 to 10% water cut.
±
.15
........................ From 10 to 15% water cut.
Output
Display: 16-character alphanumeric
Relay: SPDT rated 10 Amp at 24 Vdc.
4-20 mA: Loop powered.
Isolated to ±4 Volts Common Mode.
Enclosure
NEMA 7 explosion-proof, Class I, Division 2, Group C
and D.
Process Connections
Flange, grooved, MNPT.
Definitions
Cut - A term commonly used to describe the % water
by volume in the product stream.
S&W - The term S&W is referring to water and other
contaminants in the hydrocarbon (oil) product stream.
Grindout - A test performed on an oil sample to deter-
mine % water by volume. This is normally by centri-
fuging, but may be done by other methods.
TC - Temperature coefficient for temperature com-
pensation of the oil.
Dk - Abbreviation for dielectric constant.
Dielectric Constant - An electrical property of all ma-
terials which (in this case) is used to differentiate be-
tween water and oil.
Program Mode - To enter the calibration menu, press
the buttons in the following sequence. “Left, Left, Left,
Up, Up.” If entered incorrectly, the display will revert to
the “20mA =” menu. If this is the case, press Enter until
the unit is in normal operating mode (displaying “Cut %”
or a range error message) and start over.
Last Cut XX.XX% - This provides information only, tell-
ing what cut was entered at the last calibration.
Do Cal? YN - Pressing the left arrow will toggle the
flashing cursor between N and Y. Selecting Y and then
Enter commits you to making a grindout or cut entry. N
will put you into the Manual TC Entry Mode.
Cal With X Cut - Pressing the up arrow allows selection
of either one or two cuts. Select 1 for one-cut calibra-
tion. Select 2 for two-cut calibration with auto TC.
Enter Cut X.XX% - Enter cut or grindout value for cali-
bration.
Manual TC = XXXX - Displays TC value for temperature
compensation. Suggested default is 600 (for 5% units).
Use zero if no temperature compensation is desired.
Auto Set TC YN? - Use with second cut. Select Y to
proceed with an automatic calculation on the TC value.
Selecting N will leave the TC value unchanged.
Auto Set TC = XXXX - Resulting TC value from a TC
calculation.
Auto Set Fail/Cuts Too Similar - An advisory message
which tells you that the Auto Set TC was not successful
due to the two temperatures being too close together or
that the cut or grindout information does not agree with
the type of change expected for oils. For example, the
dielectric constant of the oil should decrease with an
increase of the temperature. If the cut information does
not match this behavior, it is deemed invalid and the
Auto Set TC operation will not be accepted.
Note: If unit responds with this error after a second
attempt to Auto Set the TC value, recheck sample to see
if water cut has changed.
20 mA = % - Allows the span of the 4-20 mA loop and
the 0-5 Vdc output to be set. The 0-5 and 4-20 are
directly linked so that 4 mA is the same as 0 Vdc and 20
mA is the same as 5 Vdc. The 20 mA point is always
considered the % water where 20 mA will be produced.
It is not useful to enter a number greater than the unit
range.
Set Pt =% - The setpoint value is that value at which the
setpoint relay will go to bypass. This is the same as the
power off relay position, i.e., the NC contact is closed.
The delay value establishes how long the instrument
observes a bad oil condition before actually releasing
the relay to bad oil. During this time, the red LED on the
front panel will flash. At the relay release, the flashing
will stop and go to solid red. When in transition from bad
Display Definitions
There are many messages used to communicate in-
formation on data entry. The messages are summa-
rized in the following:
Program Mode - To enter program mode, press all
three buttons simultaneously.
