Level Sensors & Switches

ELS-1150 Single-Point Level Switch

Part Number: 195204
Image is of similar product


ELS-1150 Series Single-Point Level Switch is a high-performance sensor that features a micro-processor board design to provide a wide range of capabilities including sinking, sourcing and time delay outputs. The strong fused glass prism eliminates leak potential and is capable of handling extreme temperature and pressure applications up to 2500 psi (172 bar). At just 1.38" (35 mm) long, the ELS-1150 is suitable for a wide-range of applications.

The stainless steel version, ELS-1150SS, is excellent for applications requiring corrosion resistance and is ideal for acids, solvents, and dielectric water applications. An explosion proof version, ELS-1150XP, is excellent for applications in Oil & Gas that require small, accurate level sensing of constant media (ie. hydraulic fluid or coolant).

  • Fused Glass Prism for High Pressures
  • Excellent Price-to-Performance Ratio
  • Ideal for Corrosive Environments


10 days
Lead-times and expedites

Lead-times apply to standard parts & configurations. Expedited shipments available by contacting factory. Lead-times may vary based on quantity and/or non-standard configurations.

CE ROHS Gems Compliant CSA


  • Fused Glass Prism for High Pressures
  • Excellent Price-to-Performance Ratio
  • Ideal for Corrosive Environments
Sensor Type
Primary Material Of Construction
Wetted Materials
Nickel Plated Carbon Steel, Fused Glass
Stem Material
Nickel Plated Carbon Steel
Float Material
Float Diameter
Actuation Level
Min. Liquid SG
Maximum Pressure
2,500 psi
Minimum Temperature
Maximum Temperature
Mounting Size
3/4"-16 Straight Thread
Mounting Style
Vertical or Horizontal
Electrical Termination
12" Long, 22 AWG, Polymeric Leads
Switch Type
TTL/CMOS Compatible
Switch Operation
Normally Closed (Non-Reversible)
12 VDC
Open Collector Sink 18 mA max.
UL Recognized, CE

Gems Sensors Instructions, ELS-1150

Format .pdf
Size 29 KB

Electro-Optic Level Switch Product Guide

Format .pdf
Size 148 KB

Gems Sensors Catalog, ELS-1150

Format .pdf
Size 553 KB
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Will different liquid media affect the time delay for optic sensors?

If the viscosity is similar, the time delay should be the same for different media.

What is the difference between "sinking" and "sourcing?"

Sinking and sourcing are terms used to describe how an associated load (the device being turned on or off by the sensor) is powered in relation to the sensor. Sinking, the more widely used of the two, involves the switching of load current (power) supplied by a power source external to the sensor. In a sinking configuration, current passes through the load first, through the output switch of the sensor second and lastly to ground. A sensor with a sinking output switches the ground, or negative, leg of the circuit. In contrast, sourcing refers to a configuration in which the sensor is the source of the current required to power the load. In a sourcing situation, current supplied by the sensor passes through the load second and then to ground. A sensor with a sourcing output switches the positive leg of the circuit.

Can you connect more than one 12 volt Sinking Electro Optic Sensor to the Opto Pak Controller?

The Opto-Pak controller was designed for just one relay output. However, when using 12 VDC Electro Optics in parallel with one Opto-Pak controller Part# 149536 or 149535 with Nema4X Enclosure, the following is possible: Maximum capability: 100Ma Maximum optic sensors: 4 For multiple sensors wired in parallel to one Opto pak Controller, the sensors will exhibit logical OR operation: Dry Sink sensors: if any sensor is dry, the Opto Pak Controller relay will be energized, and all sensors would have to be wet to de-energize the relay. Wet Sink sensors: if any sensor is wet, the Opto Pak Controller relay will be energized, and all sensors would have to be dry to de-energize the relay.

Does Gems offer an optic sensor with a time delay?

For large volume OEM applications, a custom time delay is available on the programmable microprocessor version of the ELS-1150, which can be programmed for on, off or both delays from 2 seconds to 255 seconds. All delays have a ±1 second tolerance. Call Gems for more information.

Is there a preferred mounting position for the ELS-1150 and ELS-1150XP Optical sensor?

These sensors must be mounted horizontally or up to 45 degrees from horizontal only. Reason, possible drips on tip can cause false indication. Also do not want to create air pockets.

What is the diode part number that is referenced for inductive loads per the wiring diagram for an Optic sensor?

Reference Diode part# 1N4004, (400V peak input voltage)