Omega Vehicle Security LVP-51 Series Calibration, Checking the Point of Actuation, Maintenance

CALIBRATION

Step Eight

CALIBRATION

Step Nine

After it is installed in place, the LVP-51 series must be calibrated by the user before operation. Everything needed for the procedure is self-con- tained within the electronics of the LVP-51 series level switch. Two dielectric states—full condition and empty condition—are measured by the LVP-51 series, and then averaged to set the threshold between “wet” and “dry” at the sensor. The empty state must be at least 6" below the bottom of the sensor for calibration. The full state must be to the top of the sensor (not just to the point of actuation) for calibra- tion. The actual application fluid at its intended operating temperature must be used during calibration. Use the following procedure assumes that the sensor has already been wired to a power supply.

1.Remove the cap from the sensor body by loosening the two screws located below the sensor. Do not remove the screws from the sensor. Insert a small screwdriver into the small slot at the edge of the cap and gently pry upwards.

2.Looking down you will see a small three-position switch and two trimpots marked Full and Empty. You may start with whatever state the tank is in.

3.Full state: With

Checking the Point of Actuation:

Raise the fluid level to the point		1"
where the sensor sends a “wet”		max.
signal (Input LED will turn		Full
Amber on Omega controllers). Calibration
The “dry” signal should be		Point
sent when the fluid level is	Point of
lowered (Input LED will turn	Actuation
Green on Omega controllers).	(POA)
The actual Point of Actuation
(POA) depends on many variables,
including the thickness of the wall and
				6"
the dielectric value of the liquid.		For
			min.
example, thicker tank walls can
raise the POA while thinner	Empty
walls could lower the POA.
	Calibration

Point

If the POA needs to be

changed, measure the distance and remount the sensor in a new location.

Non-conductive plastic tank wall

the	tank filled to		EMPTY OPERATE FULL
			CAL	CAL
the top of the sen-		Switch
sor, set the switch
to the Full posi-		Screw Housings	EMPTY	FULL
tion (right). Make
sure your hands or		Empty Pot		Full Pot
any	other objects
				LED
are	not touching

the sensor while calibrating because this will cause a false read- ing. Using a small nonmetallic screwdriver or alignment tool, turn trimpot Full until the LED just lights, and no farther. Note the position. Now turn the trimpot back until the LED turns off. The ideal setting for the trimpot is midway between these on and off points.

4.Empty state: With the tank drained to a point no closer than 6 inches below the bottom of the sensor, set the switch to the Empty position (left). Set the Empty trimpot as in Step 3.

5.After completing calibration, make sure to return the switch to the center position. Snap the cap back on by pressing down, and tight- en the two screws.

Operate

Empty Full

Cal Cal

Switch

Empty		Full
Pot	LED	Pot

Screws

Do not attempt to change the Point of Actuation by intentional miscalibration.

If the sensor does not signal wet and dry reliably, it may be that:

•the dielectric constant of the application fluid is too low

•the tank wall is too thick for the application fluid

•there are static or other electrical charges in the fluid

•metal objects are within 6" of the sensor

•calibration was performed incorrectly

Try the calibration procedure again, after making corrections if possi- ble. If the full and empty states are too similar dielectrically, it may not be possible to use a capacitance sensor.

Testing the Sensor:

1.Power: Apply power to sensor, by connecting power to the con- troller and/or power supply.

2.Full condition: Fill the tank with the application liquid, by filling the tank up to the sensor’s point of actuation.

3.Test: With the sensor being fluctuated between wet and dry states, use a multimeter to ensure that the correct signals are being pro- duced by the LVP-51 series level switch, or observe the sensor indicator light in the controller.

4.Point of Actuation: Observe the point at which the rising or falling fluid level causes the sensor to change state, and move the installation of the sensor if necessary.

Maintenance:

The LVP-51 series level switch itself requires no periodic mainte- nance except cleaning as required. However, periodically clean any coating or scaling on the tank wall the sensor is attached to and check the calibration. It is the responsibility of the user to determine the appropriate maintenance schedule, based on the specific characteris- tics of the application liquids. In addition, any dripping or condensa- tion between the sensor and the tank wall fitting may need to be peri- odically cleaned to maintain accuracy.