Model 107

SKU: 107

Capacitance Level Switch, Multipoint, Two or Four DPDT Relays

The Delta Controls Model 107 features all digital circuitry and pushbutton setup. It is potted for severe environments. An LCD display reads level directly in gallons, inches, meters, tons, etc. Pushbutton setup and simple two point calibration means you don’t have to fill or empty the tank to calibrate or recalibrate switching points accurately. The “ON”-“OFF” elevation is separately software selectable for each relay. The Model 107C provides two 5 Amp DPDT relays. The Model 107D provides four DPDT relays. The electronics module can be remotely mounted.


  • Intrinsically safe probe circuit is standard
  • R.F. Admittance circuitry with spike protection
  • Insensitive to process coatings and buildup
  • Large direct reading LCD display with keypad
  • Reads level directly in gallons, meters, tons, etc.
  • Pushbutton setup and calibration
  • Simple, two point calibration for multiple switch points
  • No need to empty the tank to calibrate accurately
  • Can be direct or reverse calibrated
  • Built-in self diagnostics warn of miscalibration
  • Choice of integral or remote electronics module
  • Design is accurate, simple, and very reliable
  • Process temperature range -350 to +750°F (-215 to +400°C)
  • Corrosion resistant, NACE #MR-01-75 optional
  • High or low relay fail-safe action
  • Adjustable 1-30 second time delay
  • High reliability; 100 hour operational run-in testing
  • Epoxy sealed electronics module survives harsh environments and area vibration
  • Process pressure may be from hard vacuum to as high as 10,000 PSIG (-1 to +700 bar)
  • Choose from application specific probe shapes, styles, configurations, and process connections
  • Wide choice of wetted materials includes steel, stainless steel, PTFE, PVDF, Monel, and ceramics
  • Threaded, flanged, or bracket mounting


The Delta Controls Model 107C and 107D probe type switches use RF Admittance technology to produce switching action when a material level crosses the switchpoint set on its sensing probe. Many probe configurations are available; the proper one is determined by the service.

The interface position between two liquids with different dielectric constants can be accurately detected by the Delta Controls Model 107. The unit will even average out a cloudy interface and produce a precise switching action as its position passes the setpoint. A limitation is that one of the liquids must be nonconductive. The Model 107 is not sensitive to SPG (specific gravity) variations. Water/hydrocarbon interfaces produce excellent results.

Typical Services

  • Level range: Independently programmable ON and OFF switchpoints can be anywhere along the length of the probe. The range is 0-32,000 Sensing Units; see Application Note PROB-198 for details.
  • Number of Relays:
    • Model 107C - 2 each DPDT 5A @ 250 VAC
    • Model 107D - 4 each DPDT 5A @ 250 VAC
  • Time Delay: 0.25 to 30 seconds adjustable
  • Basic Supply Voltage: 120 VAC basic (240 VAC or 24 VDC optional)
  • Operating Temperature: -40 to +180°F (-40 to +85°C)
  • Temperature Effect (0-150 F): Typically less than 0.25 inches (6mm) H2O
  • Probe Sensing Circuit: Intrinsically safe
  • Electronics Modules: Potted for high reliability.
  • Housing: 4X Hoseproof; 6 Submergible; Class 1, Division 1, Groups BCD,EFG Explosionproof optional; aluminum or epoxy/glass.

Electronics Location

Integral mounting on the probe head produces a simple one-piece unit which generally results in the lowest installed cost. Alternately, the Model 107 electronics module may be located up to 50 feet (C/F for up to 1000 feet) away from the probe. A coaxial cable connects the remote electronics to the sensing probe.

The probe may be mounted either vertically or at an angle. The material level must move past the points on the probe where switch action is to occur.


Calibration is simple and easy. The Delta Controls Type 107 can be calibrated using any two levels in the tank. The tank does not have to be completely filled or emptied. You need only change the level to get a required second known elevation.

Calibration Procedure

  1. Measure the level of material in the tank or set the level in the tank to a known level. Press the NEXT button until CAL PT 1 is displayed. Press the INCREASE or DECREASE buttons until the actual level in the tank is displayed. Then press SAVE.
  2. Change the level of material in the tank to another known level. The amount of change is not critical, however the farther apart the two calibration points are, the more accurate the calibration will be. Press the NEXT button until CAL PT 2 is displayed. Press the INCREASE or DECREASE buttons until the new level in the tank is displayed. Then press SAVE.
  3. To set up the relays, Press the NEXT button until the relay setpoints ("IN" & "OUT") are displayed. Press the INCREASE or DECREASE buttons until the "IN" setpoint is reached. Then press SAVE. Repeat for the "OUT" setpoint. This allows a reverse or direct action of any amount.


The Delta Controls Model 107 utilizes admittance technology to measure how much of its sensing probe is covered by the liquid. This is accomplished by generating a radio frequency pulse of energy which travels from the sensing probe to the ground reference (usually the tank wall). The amount of liquid between the two determines how much energy is transferred. The amount of energy flowing (very small and low level in all cases) is a highly repeatable measure of the liquid level or interface position. The amount is compared to an internal reference and produces a switching action at selected material levels.

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