SERIES 100
RF
ADMITTANCE
LEVEL SWITCHES AND TRANSMITTERS
Delta Controls' Series 100 Capacitance Probe Level Switches are a combination of Radio Frequency/Admittance and Pulse Wave technology. These instruments are used to measure the height of liquids, interfaces, and solids. Output from these instruments produce alarms, on/off control action, level indication, 4-20 mADC signals, or combinations of these functions. The size and type of probe required is dependent on the tank configuration, type of material to be sensed, and the output functions needed. Explicit selection instructions are provided for ease of engineering and correct selection.
Capacitance Theory and Admittance Principles of Operation
SUMMARY OF MODELS AND STYLES
The
Delta Controls Model 103 uses RF Admittance technology to produce switching
action when a material level crosses the setpoint on its sensing probe.
The Model 103 provides a 5 Amp SPDT contact, setpoint adjustment, and
1-60 second delay adjustment. Use for high reliability severe services.
Electronics module is potted to withstand vibration, corrosive gases,
etc.
Model 104 Tip Sensitive Level Switch
The Delta Controls
Model 104 probe type control switches when a conductive material touches
the tip of the sensing probe. More of the sensing probe must be covered
when the material is insulating and has a lower dielectric constant. The
Model 104 will sense most materials such as corn, lime, dolomite, coal,
water, acid, sodium hydroxide, and coffee.
The Delta Controls Model 105, with adjustable differential action (where the OFF setpoint is different from the ON setpoint) offers a 5 Amp DPDT contact and adjustable delay time. The electronics module can be remoted, and is potted for severe environments. The probe circuit is intrinsically safe. Used for difficult services where corrosion, vibration, etc. are a problem.
Model 107 Two and Four Point Level Switches
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.
Model 173 Two-Wire Level Transmitter
The Delta Controls Model 173 transmits a 4-20 mADC signal proportional to the level or volume in a vessel. Up to 10 fluid elevations can be programmed in to linearize an irregularly shaped tank. The unit is self checking and provides diagnostics. It is potted for service in severe environments. It will handle the most difficult services.
The Delta Controls Model IPT transmits a 4-20mA signal proportional to the interface position in a water/oil separation vessel. Process conditions can range up to 2500psig (27 MPa) and up to 500 °F (250°C)
The transmitter sensing probe can be removed from the vessel without disturbing or de-pressurizing the process. The probe is withdrawn up into a chamber located above a block valve. The valve is then closed and only the withdrawal chamber is depressurized. The sensing probe can then be cleaned in place or completely removed.
Applications include refinery desalters, crude oil production separators, reclaimed oil plants, and paper mill soap collectors.
RF Probes for use with Delta Controls RF Admittance Products
RF Admittance Probe Operating Theory
A capacitor is formed by the sensing probe and a ground plane (usually the tank wall). Delta Controls Series 100 instruments measure the amount of process material present by accurately measuring how much energy will flow from the probe to "ground" (virtual or earth) due to the capacitance effect. More energy flows as the elevation of the material between the probe and ground increases. The energy flow is directly proportional to the material elevation, and is used to produce a mADC output signal, or a precise switching action.
The amount of energy flow is a function of the probe size, ground plane distance and the dielectric constant (Dc) of the process material. The Dc of each material is a unique property specific to that particular material. This property can be defined as the ease with which AC energy can travel through the material. Empty space (Dc = 1.0) transfers the least energy and is used as a reference for materials. The Dc of a material is the ratio of its energy transfer characteristic to that of a hard vacuum. For example, gasoline has a Dc of 2.0 which means that twice as much energy will transfer through gasoline as will transfer through a hard vacuum. The Dc of a material is a function of its atomic structure and the number of its molecules present per unit of volume. A precise value of material Dc is not normally needed for Series 100 selection, installation, or calibration. If a material is conductive, then its transfer effect is adequately large and its actual Dc can be ignored. Atmospheric gases have Dc values which are very close to 1.0 and these can also be ignored. Nonconductive materials have Dc values which range from 1.5 to 55.0, and some consideration must be given to probe and range selection to insure that an adequate signal-to-noise ratio is maintained. Selection methods are described in detail in Application Notes AN-10001 and AN-10003, as well as the probe datasheets. These instruments are insensitive to coatings, material resistance variations, dielectric relaxation losses, or other common error causing phenomena. The circuitry is designed using RF/Admittance and Pulse Wave principles, to ensure that only the "capacitivity" effect determines the output signal or switching position. Extraneous effects due to conductivity variations, static charges, polarized solutions, etc. are also eliminated.
Application Note:
Delta Controls Sensing Probes
used with these level switches and transmitters
Data Sheets
By Model Number