Factory reset washes out any previous user calibration and returns the sensor to the original set points. Connect the white wire to the black wire (see manual), point the sensor into open space with no reflective targets, power it up for 2 seconds, and then power it down. The blue LED will not flash during reset.

If the sensor DOES receive a valid acoustic signal return, but the level falls below the calibrated 4 mA empty set point, the blue LED will rapidly flash on and off, and the signal output will go to 22 mA until the level rises back into the span. The solution is to perform a factory reset on the sensor, re-calibrate the span and place the 4 mA empty set point lower in the tank.

If the sensor does NOT receive a valid acoustic signal return, the blue LED will turn on, and the signal output will go to 22 mA until the sensor acquires the level. This is generally caused by the presence of substantial foam, vapor and/or turbulence.

During normal operation, the blue LED should be off and the 4-20 mA signal output should be relatively stable within the span.

Yes, as long as the total loop resistance is less than 900 Ohms.

The 4-20 mA span can be calibrated by measuring the current consumption alone with a digital multi-meter or display. During the initial moments of calibration, the sensor draws 22 mA while it's acquiring the target distance. At the time that the sensor places the set point, the current will jump down to the appropriate 20 mA or 4 mA set point and the blue LED will flash.

The 20 mA tank full set point should be placed at a distance that's greater than or equal to the riser height plus half the sensor's dead band. For example, based on an LU13 sensor, if the riser height is 6", and the dead band is 4", then the 20 mA full set point would be placed at 8".

The sensor can be reverse calibrated such that the 20 mA set point is empty and the 4 mA set point is full. Reverse 20-4 mA calibration can also help optimize the sensor's response time in applications with a fast rate of level change.

While the 4 mA and 20 mA set point calibration is not fundamentally required, it's generally recommended because it optimizes the sensor's installed performance.

It's often more convenient to target calibrate the sensor against a wall or other flat reflective surface using a tape measurer for 4 mA and 20 mA set point distance.

The sensor can be calibrated in about a minute using a 24 VDC power supply, tape measurer and flat reflective target such as a wall or liquid in the tank. To calibrate the 4 and 20 mA set points, attach the calibration wire to the appropriate power supply leg (see manual), and hold the sensor at the desired range to the target until the blue LED blinks.

The old 10-50 mA standard lost the battle to 4-20 mA due to the following benefits: 1) The same two-wires carry both the sensor power and signal, 2) 4-20 mA is easily converted to a 1-5 VDC input via a 250 Ohm, _ Watt resistor or 1-10 VDC input via a 500 Ohm, _ Watt resistor, 3) 4-20 mA is low current and therefore has a low heating loss through the signal wire, and 4) with shielded cable, 4-20 mA is noise resistant to radiated and inducted interference.

The 4-20 mA represents the sensor's measurement span. The 4 mA set point is typically placed near the bottom of the empty tank, or the greatest measurement distance from the sensor. The 20 mA set point is typically placed near the top of the full tank, or the shortest measurement distance from the sensor. The sensor will proportionately generate a 4 mA signal when the tank is empty and a 20 mA signal when the tank is full.

The sensor can be installed up to 1000 feet away from its point of termination using a shielded, 18-20 gauge twisted pair cable and 24 VDC power supply. The total loop resistance should not exceed 900 ohms.

NEMA 6 enclosure sensors are designed to resist infrequent submersion for short periods of time. NEMA 4 enclosures are designed to resist frequent splashing the equivalent of direct hose spray and should never be submerged.

If the tank has an enclosed top, to avoid signal cross talk interference, only one sensor may be installed unless the second sensor is mounted in a stand-pipe. If the tank has an open top, then two sensors can typically be applied assuming that they are installed on opposing sides of the tank with at least 10' (3m) distance between one another.

The LM50-1001 (2" NPT) or LM50-1061 (2" G) side mount bracket is a good choice. Add a 2" to 1" reducer bushing for use with 1" transducer sensors. Users often fabricate equivalent brackets based on their custom size or material requirements.

On a plastic tank, use a self-aligning bulk head fitting that enables the sensor to be rotated to the level and/or perpendicular position relative to the liquid surface. On a metal or fiberglass tank, a flange fitting with a riser that accommodates for the slope is typically the best option.

Sensors with a 1" transducer should be installed in 2" stand-pipes. Sensors with a 2" transducer should be installed in 3" stand-pipes.