1. The Level Measurement Market
This presentation will discuss the theory of how an RF Admittance point level switch operates.
Other presentations are available or will be available to cover:
RF Point Level Admittance Calibration
RF Point Level Admittance Cote Shield™

4. Point Level Theory of Operation
This presentation will discuss the theory of how an RF Admittance point level switch operates.
Other presentations are available or will be available to cover:
RF Point Level Admittance Calibration
RF Point Level Admittance Cote Shield™

5. What is Point Level?
Point level or On/Off measurement indicates the absence or presence of material at a certain point in the vessel, pit, pipe, etc…
Point level measurements are used for
High Level
Spill Prevention
Stop Fill
Low Level
Stop Empty
Refill Indication
Pump Protection
Generally speaking, there are two types of level measurements, Continuous and Point level indication.
Continuous describes a measurement that provides a measurement of the entire vessel such as 0 to 100%.
Point level provides an indication of level at a given point in the vessel. Basically, a point level switch will indicate material is absent or presence at the location of the sensing element.
This presentation will discuss Point Level switches.
Typical uses of a point level switch include overfill or spill prevention and stop fill or stop empty indication. Point level switches can be used to protect pumps from running dry. Point level switches can also be used for interface indication between an insulating and conductive material.

6. Properties of Material
A Material’s physical property does not affect RF Admittance measurements.
RF Admittance uses the product’s electrical properties to make the measurement.
Physical
Density
Viscosity
Electrical
Dielectric
Conductivity
An RF Point Level switch relies on the electrical properties of the material to make the measurement. As we discussed, Dielectric and conductivity are the properties that allow the switch to operate.
Physical properties such as Density and viscosity have no affect on an RF Admittance switch. Often, customers will bring up concerns about coatings left by viscous materials. False trips do to conductive coatings is a common problem with standard capacitance type switches. When properly applied, and RF admittance switch with Cote- Shield™ circuitry will eliminate false trips do to coatings.
Note – Cote-Shield™ theory and capabilities will be covered in depth in another presentation.

7. Dielectric Constant (K)
A=4.4 sq In
2.1”
D=1” pF
Typical Values
Material
Between
Plates K
Capacitance in
Vacuum
Air
Polyeth. Chips
Soap Powder
Kerosene
Sand
Alcohol
D.I. Water 78 78
An RF Point level switch uses the electrical properties found in all materials to make a measurement. One of these properties is Dielectric Constant symbolized by a “K”. The diagram on this slide shows a capacitor with two 2.1 inch square plates at a distance of 1 inch. This is the standard for measuring dielectric constant. Any material placed between these two plates would generate a capacitance value equal to the materials dielectric constant (example – water placed between the plates would equal 78pF or a “K” of 78).
All materials have a dielectric constant. 3

8. Conductivity (g) ScaleuS
The conductivity scale indicates the conductivity of materials in Microsiemens. For RF Point Level applications, any material with a conductivity above 1 microsiemen can be considered conductive.

9. It Starts With The Capacitor
k A
C = AC d
Conductive Plate
Conductive Plate
The basic theory behind the RF Admittance switch is a capacitor.
The formula for capacitance is C (capacitance) is equal to the K (Dielectric constant) times the A (Area of the plates) divided by the D (Distance between the plates).
Dielectric
Insulating Material

10. Factors that Affect Capacitance Distance Between Plates
We can change the amount of capacitance generated by increasing or decreasing the distance between the plates. Decreasing distance increases capacitance while increasing distance decreases capacitance.
k A
C = d

11. Factors that Affect Capacitance
Area of Plates AC
Area
Capacitance
Area
Capacitance
k A AC AC
Changing the area of the plates will also affect capacitance. Smaller plates will generate smaller capacitance while larger plates generate larger capacitance.
C = d

12. Factors that Affect Capacitance Dielectric of the Insulator
k A AC
Last, we can change the amount of capacitance generated by changing the dielectric between the two plates. Low dielectric materials will generate less capacitance the high dielectric materials.
C = d

13. The Tank and Probe form a Capacitor
Where:
C= Capacitance in pF
k= Dielectric Constant of material
A= Area of the plates
d= Distance between plates d
AMETEK Drexelbrook takes advantage of the electrical properties by turning the customers vessel into a variable capacitor.
The formula for capacitance is C (capacitance) is equal to the K (Dielectric constant) times the A (Area of the plates) divided by the D (Distance between the plates). A
k air = 1 C
k oil = 2

14. The Tank and Probe form a Capacitor
k air = 1
Where:
C= Capacitance in pF
k= Dielectric Constant of material
A= Area of the plates
d= Distance between plates d
If we increase the amount of Dielectric material between the two plates, we will increase the amount of capacitance generated. This increase is measured by the point level switch and at a predetermined threshold the switch will indicate that material is present or absent at the sensing element.
Note – We can see by the formula that we can increase the capacitance output by increasing the dielectric, increasing the area of the plates, or decreasing the distance between the plates. We can not control the dielectric constant. That is, we can not control the material the customer is trying to measure. However, in most cases we can control the size of the plates (A) and in some cases, the distance between the plates (D). A
k oil = 2 C k

15. Affects of Dielectric and Conductivity
Vertical Bare Probes 30
Water
C p (pF) 20 10
Now let’s look at the same products using a bare (un-insulated) sensor. In this case the water, being conductive, causes an infinite change in capacitance by shorting the active directly to ground. As you can see, in the case of conductive materials, the switch will be tip sensitive changing from normal to alarm as soon as the material touches the sensor.
The oil, being an insulator, gives roughly the same capacitive change regardless of the sensor being insulated or bare metal. This means that a portion of sensor will need to be covered before enough change in capacitance is “seen” to cause the bridge circuit to go from normal to alarm.
You can demonstrate this for yourself by filling two containers, one with tap water and the other with oil. Using a point level RF switch such as ThePoint, dip the tip of the sensor in the water. The unit will go from normal to alarm as soon as the sensor tip touches the water. Now, dip the senor in the oil. You will notice that you will need to cover several inches of the sensor before it will trip (Note – placing your hand on the outside of the container will insure a good ground).
Inches of Level
Bare Probe

16. Affects of Dielectric and Conductivity
Vertical Bare Probes 30
C p (pF) 20 10
Oil
The oil, being an insulator, gives roughly the same capacitive change regardless of the sensor being insulated or bare metal. This means that a portion of sensor will need to be covered before enough change in capacitance is “seen” to cause the bridge circuit to go from normal to alarm.
The relevance of this information has to do with how and when the unit will go from the normal condition to alarm. As we mentioned in earlier slide, the amount of capacitance generated by the material covering the sensing element needs to exceed the preload before it will switch. In the water application, this will happen as soon as the water touches the sensor as the change in capacitance will be almost infinite. Typically, the tuning range of the unit will be around 100 Pico farads. The change is so massive that even if we made the preload equal to the maximum tuning range (100 pF) the change due to the water would still exceed this preload causing the unit to go into alarm.
In the oil example, the capacitance change will be small. The oil covering the sensor will generate a small change in capacitance with each inch of senor covered. The actual amount of change will depend on the size of the active sensor, the “K” (dielectric) of the oil, and the distance between the active sensor and ground (C = K X A divided by D). The active length of the sensor needs to allow a capacitance change that will exceed the pre-load in order for the unit to switch.
KEY POINT – With a conductive sensor such as water, the active portion of the sensor can be very short. One half inch would be fine.
For insulating materials such as oil, the active needs to be long enough to generate a change in capacitance that exceeds the preload. We can optimize this by :
Minimizing the pre-load (High Sensitivity Electronics)
Maximizing the active portion of the sensor (A good rule of thumb is to keep the active at least six inches long)
Reduce the distance between the active sensor and ground.
Inches of Level
Bare Probe

17. What Happens Inside the Unit?
The Sensor in the vessel generates standing capacitance.
The unit is calibrated to balance the standing capacitance on the bridge circuit.
When the sensor is installed in the vessel, some amount of capacitance will be generated. This is due to the sensor being one plate of the capacitor, the ground being the second, and the dielectric in between the plates (air or gas). We call this capacitance standing or air capacitance.
The unit is calibrated to balance out the standing capacitance. If this is a manual calibration unit, this is accomplished by turning the tuning capacitor clockwise which adds capacitance to the tuning side of the bridge circuit. AS the capacitance is increased, the bridge reaches a balance point. If this is an Auto-Cal unit, this is done by the microprocessor in the unit as soon as it is powered up for the first time.

18. What Happens Inside the Unit?
An additional amount of capacitance called preload is added to make the unit stable
When the sensor is covered by material, the capacitance increases on the sensor side exceeding the preload, causing the unit to go into alarm.
An additional amount of capacitance is added to make the switch stable. This additional capacitance is called the preload. The amount of capacitance in the preload is the amount of change required to cause the unit to go from normal to alarm condition.
As the process material covers the sensor the capacitance on the sensor side increases. When the capacitance exceeds the preload, the unit will go into alarm.
Note – We will discuss calibration in depth in another presentation module.

19. What Happens Inside the Unit?
Note – For ThePoint and Intellipoint electronic units each turn of the potentiometer will ad:
4 pF per turn for Standard Sensitivity electronics
1 pF per turn for High Sensitivity electronics
Z-tron III is available in standard sensitivity only.
An additional amount of capacitance is added to make the switch stable. This additional capacitance is called the preload. The amount of capacitance in the preload is the amount of change required to cause the unit to go from normal to alarm condition.
As the process material covers the sensor the capacitance on the sensor side increases. When the capacitance exceeds the preload, the unit will go into alarm.
Note – We will discuss calibration in depth in another presentation module.

20. What does all this mean?
Because an RF Point Level switch relies on the electrical properties of the material we must pay attention to active length of the sensing element.
Conductive materials – no problem. Because conductive materials will cause a dramatic change in capacitance as soon as they touch the tip, active length need only be a stub (1/2 inch active is OK)
Insulating material – because the change in capacitance in insulating materials is based on the dielectric, some amount of sensor will need to be covered in order to exceed the pre-load and cause the switch to change state. (8 inches of active is a good rule of thumb. If you must have less,
discuss with the factory).
As we discussed in the Theory of Operation presentation, the physical properties of the material being measured have no affect on an RF Admittance point level switch. This statement is true because of the addition of Cote-Shield™.

21. 3-Terminal Cote-Shield™ Probe (Typical Construction)
Insertion Length A
C.S.L.
Three main parts of a three terminal sensor are – Active, Cote-Shield, and Ground C

22. Increase Surface Area for Greater Sensitivity (Bare Sensing Elements Only)
WELD
WELD
ADD A HORIZONTAL SECTION
INCREASE PLATE SIZE
WELD
EXTEND THE LENGTH

23. What about measuring Solids?
One of the great things about RF switches is versatility!
One switch can measure:
Conductive or Insulating liquids
Slurries
Solids
As we discussed in the Theory of Operation presentation, the physical properties of the material being measured have no affect on an RF Admittance point level switch. This statement is true because of the addition of Cote-Shield™.

24. We can also measure Interface applications with RF point level.
Remember, we can set the switch to ignore the upper insulating phase and only respond to the conductive phase of the interface.
We can calibrate the switch so that it is not sensitive enough to respond to the upper insulating phase (oil). If we then set the switch for low level, it will be in the normal condition when covered with water and will go into alarm when the water drops below the sensor and it is covered in either the oil phase or gas phase.

25. Properties of Material
A Material’s physical property does not affect RF Admittance measurements.
RF Admittance uses the product’s electrical properties to make the measurement.
Physical
Density
Viscosity
Electrical
Dielectric
Conductivity
As we discussed in the Theory of Operation presentation, the physical properties of the material being measured have no affect on an RF Admittance point level switch. This statement is true because of the addition of Cote-Shield™.

26. So what about viscous materials that leave coatings?

27. The Capacitance Disadvantage:
Affected by Conductive Coatings
Capacitance
No current flow
Current flow
False Alarm!
To start with, we should look at how a standard (non-admittance) capacitance switch deals with coatings. A capacitance switch is similar to an RF Admittance switch in that it makes the vessel into a variable capacitor(Ref. Slide # 4 in module #1). The switch then looks for a change in capacitance to go from normal to alarm.
When a conductive material covers the sensor and leaves a coating, the coating offers a low resistance path to ground. Because of this, current can flow from the active portion of the sensor to ground. The switch will respond by staying in alarm even though the actual material level has fallen away from the sensor again.
It is possible to use a standard capacitance switch in materials that leave conductive coatings if the sensor is mounted Vertically from the top of the vessel and the material being measured never reaches all the way to the mounting gland (ground). That is, the coating is only on the end of the active portion of the sensing element and there is no low resistance path to ground.

28. The Capacitance Disadvantage:
Affected by Capacitive shift due to temperature changes
Capacitance
False Alarm!
Another problem that can develop with standard capacitance type switches is false trips due to capacitance changes in the gland due to temperature changes. As the temperature drops, the capacitance of the gland increases. If the capacitance increases to a point that the preload is exceeded, the switch will go into alarm.
Capacitance of the mounting gland changes with temperature changes

29. Not Affected by Conductive Coatings
The RF Advantage:
Not Affected by Conductive Coatings
We correct for these limitations in the old style capacitance switch by adding a third element to the sensor. Along with the active and the ground, the new element is called the cote shield. The cote shield element is driven at the same electrical potential as the active portion of the sensor. This also drives the conductive coating at the same potential as the active. In order for current to flow, you must have dis-similar potentials. That is, if the potential is the same in the coating covering the active as it is in the coating covering the cote-shield, no current can flow. So, the only path for the current to flow to ground is through the material being measured.
With proper selection of sensing element and electronic units we can ignore coatings with a resistance as little as 10 ohms.
The shield also isolates the active sensor from the ground. This isolation eliminates the problem with changing gland capacitance due to changes in temperature.

30. Cote-Shield Demonstration.
We correct for these limitations in the old style capacitance switch by adding a third element to the sensor. Along with the active and the ground, the new element is called the cote shield. The cote shield element is driven at the same electrical potential as the active portion of the sensor. This also drives the conductive coating at the same potential as the active. In order for current to flow, you must have dis-similar potentials. That is, if the potential is the same in the coating covering the active as it is in the coating covering the cote-shield, no current can flow. So, the only path for the current to flow to ground is through the material being measured.
With proper selection of sensing element and electronic units we can ignore coatings with a resistance as little as 10 ohms.
The shield also isolates the active sensor from the ground. This isolation eliminates the problem with changing gland capacitance due to changes in temperature.

31. Cote-Shield Mounting Consideration
Cote-shield must extend at least 50mm (2”) beyond the mounting and the typical expected wall build up.
In order for the cote shield to be effective, it must reach into the vessel and through the typical wall build up. If the cote shield section of the sensor is inside a nozzle the coating will provide a path directly from the active to ground negating the effect of the cote shield.

32. Key Points
The basic formula for capacitance is C = K times A Divided by D.
We turn the customers vessel into a variable capacitor.
Calibration balances the bridge circuit for standing capacitance and adds a preload.
The switch will go from Normal to Alarm when the measured capacitance exceeds the preload.

33. Key Points
Conductive materials will cause a large (almost infinite) change on bare, un-insulated sensors.
Insulating materials will cause a smaller change in capacitance based on their dielectric.
RF Admittance uses electrical properties of materials to measure level. Physical properties such as viscosity and density have no affect.

34. RF Point Level Products
Now let’s look at point level controls. Point level controls indicate the absence or presence of materials..

35. RF Point Level Family Z-tron III™ ThePoint™ Intellipoint™
General Purpose
ThePoint™
Agency approvals
Available with most sensing elements
Intellipoint™
Agency Approvals
Auto-Verify™, Dual Compartment Housing, SIL

36. IntelliPoint The Intellipoint is our premium point level switch.
Dual compartment housing.
Integral or Remote mounting.
Auto Verify and Manual Certify standard
0 to 60 second time delay (forward or reverse)
100 amp spark protection built in
Auto ranging power supply (Relay Version)

37. IntelliPoint Output Relay (Line Power) Current (two Wire)
Two SPDT relays (One for alarm, one for fault)
Option for Gold Plated Relay contact
Current (two Wire)
8mA Alarm/16mA Normal/22mA Fault Or
8mA Normal/16mA Alarm/5mA Fault

38. IntelliPoint Calibration Auto calibration Manual Calibration
Standard Sensitivity 2pF or 10pF preload
High Sensitivity 0.5pF or 2pF preload
Manual Calibration
Standard Sensitivity
High Sensitivity

39. IntelliPoint Products
Two Wire Intellipoint with SIL Rating
What is a Safety Instrumented System (SIS)?
A system designed to respond to hazardous or potentially hazardous plant conditions. The SIS is designed to take the process to a safe state when predetermined conditions are violated.
Also called Emergency Shut Down System (ESS or ESD) and Safety Shut Down (SSD)
A rigorous risk assessment is required to determine the appropriate Safety Integrity Level (SIL) for each process loop. Level range from SIL 1(lowest Risk) to SIL 4 (Highest Risk)
SIL Intellipoint conforms to SIL 2

40. IntelliPoint Product FM Approved CSA Approved ATEX Approved
Line Powered Intellipoint™, Integral
Approved for use with FM approved Explosion Proof sensors only
(See for list)
Approved for use with , 022, 024, and 028 Perm-A-Seal™ sensors only
Line Powered Intellipoint, Remote
Approved for use with all sensors
Two Wire Intellipoint, Integral
Two Wire Intellipoint, Remote

41. ThePoint™ Mid-Range RF point level switch
RF point level device is positioned in price between the Z-tron III and the Intellipoint
Single Compartment Housing
Integral or Remote mounting.
Available with all high use Sensing Elements
0 to 60 second time delay (forward or reverse)
100 amp spark protection built in

42. ThePoint™ Output Relay (Line Power) Current (two Wire) DPDT relays
Option for Gold Plated Relay contact
Current (two Wire)
8mA Alarm/16mA Normal Or
8mA Normal/16mA Alarm

43. ThePoint™ Calibration
Auto Calibration and Manual calibration are standard in ThePoint product.
Standard and High Sensitivity are also standard.

44. ThePoint™ Product FM Approved CSA Approved ATEX Approved
Line Powered ThePoint™, Integral
Approved for use with FM approved Explosion Proof sensors only
(See for list)
Approved for use with , 022, 024, and 028 Perm-A-Seal™ sensors only
Line Powered ThePoint, Remote
Approved for use with all sensors
Approval for use with all sensors
Two Wire ThePoint™, Integral
FM approved Explosion Proof sensors only
Two Wire ThePoint, Remote

45. Z-tron III
Z-tron III™ is our economical general purpose point level switch
Integral Only
Available with general purpose PEEK Sensor
120VAC, 240VAC, or 24 VDC
Calibration through potentiometer

46. Z-tron III
0 to 60 second time delay forward or reverse acting (Adjustable rotary switch)
100 AMP Spark protection
The Z-tron III has General Purpose UL/CUL approval
CE Mark EEC Directive 89/336

47. Z-tron III
General Purpose Level Switch
OEM Accounts
Door Opener

48. Other RF Point Level Products
Multipoint – Line Powered point level offers 3 control points on one sensor
series
Three DPDT relays
120 and 240 VAC
Multiple control points with one sensor (3 points)
One point can be set up as a differential for pump on/off control

49. Other RF Point Level Products
Clear Line – series
None intrusive sensor for absence or presence of material in a pipe
Pump Protection
Low level in lined vessels
Interface
DPDT Relay

50. Key Point Level Applications
Now let’s look at point level controls. Point level controls indicate the absence or presence of materials..

51. QR1 Allows you to fully describe the application.
Sketch is helpful for us to understand.
Serves as a checklist.
Avoid having to go back for more info.
Receives priority in Applications.
Avoid problems at Tech Check.
Material, max. pressure and max. temperature always required.

52. Chemical Industry Point Level Key Applications
Chemical storage – overfill prevention
Dry Chemical Storage – High and Low level
Rail Car and Truck Loading – Overfill Prevention
Leak Containment Dykes
Pump “Run Dry” Protection
Continuous Level Back Up
Generally speaking, there are two types of level measurements, Continuous and Point level indication.
Continuous describes a measurement that provides a measurement of the entire vessel such as 0 to 100%.
Point level provides an indication of level at a given point in the vessel. Basically, a point level switch will indicate material is absent or presence at the location of the sensing element.
This presentation will discuss Point Level switches.
Typical uses of a point level switch include overfill or spill prevention and stop fill or stop empty indication. Point level switches can be used to protect pumps from running dry. Point level switches can also be used for interface indication between an insulating and conductive material.

53. Petroleum Production and Refining Point Level Applications
Storage Tank Spill Prevention
Separator Interface Measurement
Water Draw Off Low Level Alarm
Leak Containment Dike
Rail Car and Truck Loading – Overfill Prevention
Processing Vessels – High and Low Level
Continuous Level Back Up
Generally speaking, there are two types of level measurements, Continuous and Point level indication.
Continuous describes a measurement that provides a measurement of the entire vessel such as 0 to 100%.
Point level provides an indication of level at a given point in the vessel. Basically, a point level switch will indicate material is absent or presence at the location of the sensing element.
This presentation will discuss Point Level switches.
Typical uses of a point level switch include overfill or spill prevention and stop fill or stop empty indication. Point level switches can be used to protect pumps from running dry. Point level switches can also be used for interface indication between an insulating and conductive material.

54. Spill Prevention 4-20 mA Alarm Fault LCT Receiver PLC DCS Computer
High Level
High-High Level
Alarm
Fault
LCT
Receiver
PLC
DCS
Computer
Spill prevention is becoming more and more important with EPA, OSHA and NFPA (National Fire Protection Agency) regulations becoming more stringent on spilling hazardous, polluting, flammable or combustible materials. And the list of materials being regulated is becoming longer every day. NFPA Code 30 and 30A, Paragraph b and c now state (Revised in 93) that tanks with hazardous materials must be equipped with high level alarm devices which are independent of any tank gaging equipment. The same recommendation is made by API (American Petroleum Institute) recommended practices OSHA and EPA are more concerned with fining you and auditing you after you have the spill and figure that you’ll figure out on your own what you need to do to prevent spills.
Drexelbrook's Maximum Security system is the answer and the best system on the market today. Here we have a typical two wire on/off spill prevention system. We show on integral and one remote transmitter, which communicate to a receiver over a twisted pair. The receiver gives you relay outputs for centralized alarming and control capabilities. All these units have the ability to be tested remotely by the push of a button or automatically every ten seconds. It is possible to tie the receiver to a PLC, DCS or any other computer, via RS 232/485 connections. This system is very versatile in how you configure your set-up and gives you the ultimate in spill prevention protection.

55. Spill Prevention Used to prevent overfilling of materials.
Overfill recommended practices such as API 2350
Federal Regulations such as 40 CFR 112
SPCC – Spill Prevention Control and Countermeasure plans

56. Interface Provides “Dump” control for separation applications
Oil / Water Separator
water
oil
Interface
This next application is often found in the oil refinery business but occurs any place where water can accumulate in product and interface out. It is advantageous to keep the amount of water in the vessel to a minimum, making it possible to store the maximum amount of product. In this case, a point level control is installed near the bottom of the vessel. It is connected to a pump that will begin drawing off when the interface reaches the probe and a timer can shut the pump off after a defined period. Again, with the high price of materials these days, for example petroleum, you wouldn't have to send much oil out with the water to justify the price of the controls. Or perhaps worse yet, you may have to pay fines for polluting the effluent stream.

57. Interface Application
Separator vessels in industries such as petroleum, refining, chemical, etc.. Will often have a continuous level transmitter to track the interface however, a point level switch ensures that product is not dumped with the water.

58. Power and Co-Gen Point Level Key Applications
Fly Ash ESP and Bag House hoppers
Coal feed conveyor – Empty Belt Detection
Plugged Chute Detection
Lime Slurry Mix Tanks
Sumps
Continuous Level Back Up
Generally speaking, there are two types of level measurements, Continuous and Point level indication.
Continuous describes a measurement that provides a measurement of the entire vessel such as 0 to 100%.
Point level provides an indication of level at a given point in the vessel. Basically, a point level switch will indicate material is absent or presence at the location of the sensing element.
This presentation will discuss Point Level switches.
Typical uses of a point level switch include overfill or spill prevention and stop fill or stop empty indication. Point level switches can be used to protect pumps from running dry. Point level switches can also be used for interface indication between an insulating and conductive material.

59. Fly Ash Hopper Level Electrostatic Precipitators and Bag Houses
High Voltage Grids
or filters
CAA (Clean Air Act) of 1970
amended in 1990
Another very common application for point level control is a fly ash precipitator. In coal-fired power plants, stack gasses are run through an electrostatic precipitator. The particulate matter is attracted to high voltage grids and dropped into the fly ash hopper. After a while, the fly ash hopper fills to a point near the high voltage grids. At this time, it is necessary for the materials handling equipment under the vessel to pull away the fly ash that has accumulated before it is able to touch and short out the electrostatic grid. A typical power plant may have 50 or more of these fly ash hoppers for each coal fired generator.

60. Fly Ash Hopper Level Typical Fly Ash Producers
Coal or Oil Fired Power Plants
Trash-to-Energy Facilities
Steel Mills
Coke Ovens
Foundries
Pulp & Paper Co-Gen

61. Fly Ash Hopper Level
Many facilities are looking to replace traditional Nuclear switches used for this application.
Fly Ash level switch projects are often substantial in size. It is not uncommon for 100 plus switch requirements.
The price of natural gas has re-invigorated coal fired power generation.

62. Flush Chute Probe...detects plugged chutes
3 Terminal
Flush Chute Sensor
Presence or absence of Material
Flush Mounted with Bin Wall
Intellipoint or ThePoint electronics
The next application utilizes a flush chute probe. I have one here that you can look at. This probe is mounted on the side of a vessel or chute and senses when material is lying against it. A typical application is the detection of coal plugging a chute. As you can see the sensing element offers no obstruction inside the chute since it is flush mounted. This same sensing element is equally applicable to other products such as wood chips, grains, plastic pellets, etc..
It is a great choice for low level granular applications. This eliminates the concern of the sensor bending.
With conductive materials like coal it is important to mount so the materials keep the face clean.

63. Plugged Chute Detection
Industries
Aggregate & mining
Power (coal yards)
Pulp & Paper
Recycle facilities
Agricultural products
Many facilities are replacing nuclear switches.
These are often substantial orders

64. OEM Opportunities Material Handling Pneumatic Conveying
Solvent Recovery
Evaporators
Dust Collectors
Extruders
Industrial Vacuums
Oil/Water Separators

65. Point Level Common Installation Problems

66. Common Installation Problems
Cote-shield must extend at least 50mm (2”) beyond the mounting and the typical expected wall build up.

67. Common Installation Problems
A typical problem in solids measurement

68. Common Installation Problems
Sensor location is important.

69. Common Installation Problems
Sensor location is important. Don’t forget C=K A D

70. Common Installation Problems
Remote Connection Cables
A common field problem occurs when Customers shorten cables and do a poor job of re-terminating. Cable termination kits are available which provide the correct components and instructions for proper termination.

71. Common Installation Problems
Minimum Active
C=KA D
Conductive Materials – Rule of thumb = ½ inch
Insulating Materials – Rule of thumb = 8 inches
Granular materials – Bulk density less than twenty pounds per cubic foot – use high sensitivity

72. Common Installation Problems
Conduit needs to be installed so condensation does not flood the unit housing.

73. Common Installation Problems
Other Installation Considerations
NPT mounted sensors
Do not use excessive amounts of Teflon™ tape when installing threaded sensing elements to ensure proper electrical contact with vessel.
Flange mounted sensors
Keep mating surfaces and bolts free from paint and corrosion to ensure proper electrical contact with Vessel.

74. Temperature Limitations
Maximum Ambient temperature for our Point Level electronic units are between 140F and 158F (model dependant).
Ambient Temperature “completely surrounding, encompassing” – Random House Collegiate “existing or present on all sides” Webster’s
Use Remote electronics when the temperature exceeds the specification

75. Increasing Active Length
Before welding bare rod to increase active, disconnect all wiring to the electronic unit.
WELD
WELD
ADD A HORIZONTAL SECTION

76. Common Installation Problems
Auto-Calibration Feature
Auto-Calibration occurs when the switch is powered for the first time. Powering the switch on a bench requires a re-calibration when installed in the vessel.
Material being measured must be below the sensing element when the unit is powered up for the first time.

77. Flashing LED’s
Both ThePoint and Intellipoint provide diagnostics in the form of flashing LED’s
Over Range = The circuit is seeing more capacitance on the sensing element side of the bridge then it can balance out – padding may be required.
Causes
Sensor is too long (padding required)
Sensor is touching internal tank obstruction that is grounded
Auto-Calibration feature was powered up for the first time with material covering the sensing element.

78. Flashing LED’s
Under Range = The sensing element in the vessel should generate some standing capacitance. If the unit does not see this capacitance, it will show an underage fault.
Causes
Electronic unit is not connected to the sensor (Wiring harness, ThePoint back plate pins)
Electronic unit is damaged

79. Flashing LED’s ThePoint (Line Power and Two Wire)
Blinking Red LED = Under range
Blinking Green LED = Over range
Intellipoint Line Powered
Relay#1 LED Blinking = Under Range
Relay #2 LED Blinking = Over Range
Both #1 & #2 Blinking = Verify Fault
Intellipoint Two Wire
Red LED Blinking slowly (once per sec) = Under Range
Red LED Blinking quickly (4 X per sec) = Over Range
Red & Green LED Blinking = Verify Fault

80. Flash Programmer “Black Box”
The “Black Box” is an interface between ThePoint or Intellipoint and a PC.
The following information can be displayed:
Time Delay
Auto-Verify condition (Intellipoint)
Relay 2 Mode (Intellipoint)
Failsafe
Air capacitance
Uncovered capacitance
Covered capacitance
Set Point
Real Time Probe Capacitance
Status
Model #

81. TROUBLESHOOTING Separate the system into its main components
Electronic unit
Connecting cable
Sensing element

82. Standard Unit Test
1 Disconnect the sensing element at the electronic unit
If an external padding capacitor is used remove it.
3 Adjust the setpoint adjustment to find a tune point 4 5
Observe no more than 1/2 turn between LED on and
LED off
If no tune point can be found or there is > 1/2 turn between LED on and LED off the chassis may be defective.

83. Checking The Relay
OHMS OR
115V Lamp
115VAC

84. GROUND CW
SHIELD
Check for shorts
Coax Cable Check-out

85. GROUND CW
SHIELD
CENTER 8
Check for continuity
COAX CABLE CHECK OUT

86. MINIMUM RESISTANCE READINGS
SENSING ELEMENT CHECK
Disconnect
Coax
GREEN
GROUND
SCREW
MINIMUM RESISTANCE READINGS
ThePoint/
Intellipoint Z-tron III
CW - G
S - G
CW - S
SENSOR NOT COVERED

87. INTERCONNECTING COAX CABLE....
THERE ARE 3 TYPES OF COAX CABLE
1 PVC JACKETED (Standard)
2 HIGH TEMPERATURE TFE JACKETED
3 COMPOSITE HIGH TEMPERATURE
WHAT ABOUT SHORTENING ?

88. Yes you can ! DREXELBROOK STABILIZED CABLE
TYPE XX - 12
Length in feet
CAUTION: Cable length is critical to many applications.
Do Not Shorten this cable without consulting factory.
Excess cable may be coiled in any convenient location.
DREXELBROOK ENG. CO.
(215)

89. Commonly asked installation questions
Do I need to run the coax in conduit?
Can I shorten the probe?
Can I lengthen the probe ?
Can I bend the probe ?

90. Hands On RF Point Level Calibration Fail Safe Time Delay
Mode Selection