Technical Info » Electrolytic Tilt Sensor Terms & Definitions

Impedance at Null	Fluid impedance expressed in ohms between active electrodes and common electrode with level null position under standard test conditions.
Linearity	Variation around the best straight line from null to full-range output.
Maximum Operating Temperature Range	Maximum temperature range over which level may be operated without failure.
Null Current	AC current per leg as measured under standard test conditions with level in the electrical level position. Null currents shown are maximum; level performance improves as null current is reduced. For most levels and/or applications, currents of 100 to 500 microamperes are recommended.
Null Repeatability	Maximum variation in null voltage when level is displaced and returned to null position under standard test conditions.
Null Voltage	Minimum output as measured under standard test conditions with level in the electrical level position.
Operating Range	Angular displacement each side of null through which the level will operate at the maximum average sensitivity. Expressed in arc minutes or degrees.
Operating Temperature	Temperature range within which sensor will operate and not exceed 10% of typical operating specifications.
Output Curves	Output curves shown are standard. They can be varied widely by changing configuration, electrolyte or electrodes. Consult the factory for solutions to your specific requirements.
Output voltage	Values recorded at 30 seconds (time) after an angular deflection of the level.
Sensitivity	Change of output voltage per arc second, arc minute or degree of tilt. Expressed in graphic form using standard test conditions.
Standard Test Circuit	12.5 Volts AC at 400 Hz 1k Bridge. See separate circuit for On-Off Switch.
Standard Test Frequency	400 Hz ±10 Hz usable from 25 Hz to well over 20 KHz.
Standard Test Temperature	+25°C (±1°C).
Symmetry	Maximum variation in output voltage when the sensor is tilted 50% of operating range each side of null under standard test conditions.

Standard Sensor Test Circuitry The following 1k bridge test circuit was used to determine all sensor output sensitivity figures published herein. Tests were conducted at a temperature of +25°C using 12.5 Volts AC at 400 Hz. CAUTION! – Ensure that all test and operating circuits are entirely free of direct current. Direct current will cause level damage and/or instability.

AC to DC Conversion Circuitry

This circuit converts the AC level signal to a zero-center DC output to indicate a positive or negative voltage depending on direction of tilt. It also ensures that direct current is thoroughly isolated from the level.

• NOTE: R1, R2 should be as large a value as possible to draw absolute minimum current through level at null. Lower currents assure better stability and long-term optimal performance.
• R3 to R6 approximately equal to R1, R2 individual value
• C1, C2 should be 1.5 mfd
• D1 to D4 should be IN459 or equal
• Zero Adj. approximately 10% of R3 to R6 individual value
• AC Input and R1, R2 should be adjusted for a current of 0.3 to 1.0 mA per leg at null