What this level switch does
The 76951-6011 is a non-contact ultrasonic level switch for lube-oil and industrial tanks. It works like sonar: the unit sends a pulse, measures the echo time-of-flight to the liquid surface, and changes its output when the level crosses a programmed point. Up to 3 switching points can be set in one tank, and all configuration is done on four DIP switches instead of software. Because nothing touches the liquid, it suits tanks where a moving probe would foul. It mounts upright on the tank cover and works with stations built around a plastic reservoir.
It pairs with DCB pumps with optional level switch on compact packages and complements a pressure-side monitoring counterpart on the pump outlet.
Declared specifications
Declared values are listed below; range is measured from the sensor face outward.
| Parameter | Declared value |
|---|---|
| Detection range | 60-550 mm from the sensor face |
| Switching points | Up to 3 in one tank |
| Supply | 20-252 V AC/DC |
| Current draw | 70 mA at 30 V DC |
| Maximum | 150 V DC or 252 V AC |
| Resolution | Within 2 mm |
| Configuration | Four DIP switches |
| Mounting | Upright on tank covers |
| Weight | 6 lb (about 2.7 kg) |
How the DIP switches configure it
Four DIP switches behind the cover set the whole behaviour of the unit.
| Switch | Function | Settings |
|---|---|---|
| SW1 | Sensitivity | High for thin liquids, low for thick oils |
| SW2 | Output mode | Normally open or normally closed |
| SW3 | Fail state | Output stays ON or goes OFF |
| SW4 | Response speed | Fast about 1-2 s, slow about 3-5 s |
Set SW1 for the liquid: thin liquids echo strongly and suit high sensitivity; thick oils weaken the pulse and need low sensitivity. SW3 decides whether a fault leaves the output ON or takes it OFF.
Placing switching points correctly
Ultrasonic sensing has a dead band: the nearest zone in front of the sensor face cannot be measured, so no switching point may sit inside it. Keep the high-level point at or beyond the dead band; check the manual for its width. An adequately wide tank lets the beam see open liquid, not the wall. Tank height is not measuring range: every distance works from the sensor face.
Think in points and windows. A switching point fires at one level; a pump-control pair, such as pump-on low and pump-off high, forms a window whose gap decides how often the pump runs. Foam and condensation are two different failure modes: a foam layer can become a false echo surface and report the level high, while condensation on the face weakens the pulses. Keep the face clean and dry.
Float switch vs ultrasonic
A float switch is a mechanical device in the liquid; this unit measures the surface distance through the air.
| Concern | Float switch | Ultrasonic switch |
|---|---|---|
| Moving parts | Mechanical float and contacts | None |
| Specific gravity | Must suit the fluid density | No dependence |
| Fluid contact | Float sits in the liquid | Nothing touches the liquid |
| Switching points | Usually one | Up to 3 |
| Configuration | Fixed by hardware | Four DIP switches |
Installation and wiring notes
Mount the sensor upright on the tank cover so the beam strikes the surface squarely, with clear space under the face. Aim away from fill streams and agitators, since stray echoes can shift a switching point. In washdown areas, confirm the enclosure rating before installing.
The output is a relay contact, not a motor starter: it switches a control circuit, but a pump motor needs an interposing relay sized for the load. Match SW2 and SW3 to that relay and your fail state. Before relying on it, fill and drain the tank with actual liquid and confirm every point fires where expected. If supply, load, or mounting geometry is unclear, contact us for a quote before ordering.
Frequently Asked Questions
What is the 76951-6011 ultrasonic level switch?
It is a non-contact level switch that uses echo time-of-flight to detect liquid level in a tank. It sets up to 3 switching points using four DIP switches, with no software required.
Why choose non-contact sensing over a float switch?
There are no moving parts to wear, and the reading does not depend on fluid specific gravity. Nothing touches the liquid, which keeps the fluid clean.
How many switching points can it manage?
It supports up to 3 switching points in one tank. Each point is assigned its own distance from the sensor face.
What is the measuring range?
The declared detection range is 60-550 mm from the sensor face. Tank height is not measuring range; always work from the face.
What supply voltage does it need?
It accepts 20-252 V AC/DC and draws 70 mA at 30 V DC. The stated maximum is 150 V DC or 252 V AC.
What do the DIP switches set?
SW1 sets sensitivity, SW2 sets normally open or normally closed output, and SW3 sets the fail state. SW4 sets response speed, fast about 1-2 s or slow about 3-5 s.
Where is it used?
It is used on lube-oil and industrial tanks across automatic lubrication installations. Common spots include reservoirs feeding a grease pump and compact pump packages.
Can it control a pump automatically?
Yes. The relay output switches a control circuit, not a motor starter, so size an interposing relay for pump loads.
How do I install and maintain it?
Mount it upright on the tank cover and test every switching point with actual liquid. Keep the face clean and dry; for application help, contact us for a quote.
Who builds and supports this unit?
IsoHiTech Lubrication Systems, founded in 2023, engineering since 2006, builds and supports every unit. Email inquiry@isohitech.com for specifications and a quotation.
