Design StandardThe LevelCom 100 has been designed to meet the requirements of 46 CFR 62.25-30 and
the American Bureau of Shipping (ABS) 1994 Rules for Building and Classing Steel Vessels,
Part 4-Machinery Equipment and Systems.
Approvals US - UL916 - Process Control Equipment, File E185105
Canada - CUL C22.2 No. 142-1987
ABS Type Approval, Certificate PO 2123885-X
Power 115VAC / 100mA / 60Hz - Fuse: 2A
24VDC / 500mA – Fuse: 2A
Supply Air Regulated pressure varies with input sensor range (see below). Filtered to 40 microns
Temperature Operating range: -10° F to +140° F (-23.33° C to +60° C)
Humidity 5 - 95% RH non-condensing
Enclosure UL listed as “Rain tight/Indoor use only”. NEMA 4
Constructed of .090" 5032 H32 powder coated aluminum alloy.
All fasteners are 304 stainless steel
Dimensions 14.5" (37cm) H x 5.5" (14cm) W x 3.8" (9.6cm) D
Alarm Setpoints Four (4) programmable internal setpoints
(Relay option required for remote alarm activation)
Control SetpointsFour (4) programmable setpoints
(Control 1 & 2 On/Off) (Relay option required)
Security User defined 1 - 9 character password protection
Options Alarm/control relays: 2 - SPDT “Form C” relays (contacts rated “Pilot Duty”)
Communications: RS232 / RS422 / RS485 / Modbus RTU
Automatic specific gravity compensation
Differential Pressure compensation
Integral piezoelectric alarm horn
Analog output: 4 - 20mA
Tank Sensing Range
O)
(H
2
Accuracy (Full Scale)
Resolution (Full Scale)
Supply Air Pressure
0 – 31 ft. (9.45m) 0 – 62 ft. (18.9m) 0 – 90 ft. (27.43m)
Bubblers are one of the oldest remote level sensing systems. They operate by measuring
the air pressure required to blow bubbles from the end of a pipe that is a fixed distance near
the bottom of the tank. This pressure reading is converted to liquid depth if the specific
gravity of the measured fluid is known. This ability, to measure the fluid depth remotely is
one of the most important characteristics of bubblers. No sensitive electronics or machinery
are submerged or exposed to the tanks contents, only a piece of pipe that is constructed of
materials compatible with the fluid is placed in the tank.
Older bubbler systems were of the continuous flow type and they constantly admitted air into
the bubbler pipe. The tank measurement was then indicated by a pressure gauge. This
pressure gauge was often a mercury filled manometer. The continuous flow of air can cause
measurement errors if the flow rate is too high and continuous flow systems usually cannot
detect problems in the bubbler pipe system.
The LevelCom 100 is a microprocessor based pulsed bubbler system. In contrast to
continuous flow bubblers the LevelCom 100 uses measured charges of air (pulses) to verify
that the bubbler pipe is clear of liquid. Pressure readings are taken with no air flow,
eliminating flow rate caused errors, and allowing the detection of leaks in the sense line
system. The LevelCom 100 measures the static pressure at the end of the bubbler pipe.
Using the programmed value for the liquid specific gravity this pressure reading is converted
to a depth reading. This raw depth reading is then converted for display in engineering units
of measure which include:
• Depth expressed in inches, feet, feet/inches, centimeters or meters
• Volume expressed in gallons, liters, cubic feet or barrels
• Weight expressed in short, long or metric tons
Volume and weight are calculated through a user configured tank curve. Any unit may be
displayed in ullage or innage.
The LevelCom 100 calculates the values and displays them on the front panel as 0 to 100%
of tank depth on the bar graph indicator and in the desired units of measure (as depth,
volume or weight) on the digital display.
The instrument is available in four sensor ranges:
• 0 to 31 feet (0 to 9.45 meters)
• 0 to 62 feet (0 to 18.9 meters)
• 0 to 90 feet (0 to 27.4 meters)
• 0 to 180 feet (0 to 54.9 meters)
The LevelCom 100 uses computer controlled solenoid valves, admitting pulses of air to the
system only as needed to balance against changes in the liquid level. The unit can be
configured to operate from either supply air from a compressor or a nitrogen gas bottle. In
instances where a high-pressure bottle is used as the supply for the operating gas the
LevelCom 100 can be configured for minimal gas consumption.
For operation, the LevelCom 100 simply requires electrical power, a source of clean, dry air
and connection to a bubbler pipe in the tank. When power is applied, the LevelCom 100
performs a diagnostic check of system operations. To ensure accuracy, the instrument
performs a “hardware zero” by sampling the atmospheric air pressure external to the
instrument. In normal operation the LevelCom 100 automatically performs the hardware zero
at half hour intervals. This eliminates errors caused by drift of the sensor zero due to
temperature changes.
The LevelCom 100 automatically performs a purge of the bubbler pipe at power up. The
machine can be configured to purge the bubbler pipe regularly at a user-defined frequency
ranging from one hour to one week. The user also can establish the duration of the purge
with a range from five to 120 seconds. This guarantees that the machine enters normal
operation with the bubbler pipe purged of any liquid.
Each LevelCom 100 is field configured with the parameters and feature selections associated
with the tank to be monitored. These include:
• Depth in English or metric units
• Volume in gallons, liters, barrels or cubic feet
• Weight in short, long or metric tons
• 10 point Tank Table defining the relation of depth to volume/weight
• Timing of sample and purge cycles
• Specific gravity
• Four alarm points with hysteresis
• A user defined password
• A Hot Menu to access certain user-selectable features without a password
Units of measure (depth, volume and weight) may be changed after initial configuration
without reprogramming the unit. For example, if the LevelCom 100 is configured to measure
depth in feet/inches and later it becomes necessary to change to metric units, the user simply
changes the depth unit of measure. The LevelCom 100 will automatically convert the English
value and display the correct depth in metric units. Tank table and alarm setpoint units are
also automatically converted at the same time.
The LevelCom 100 is self-diagnostic and will detect some hardware errors, bubbler pipe
and supply line problems including leaks, plugged lines and low supply air pressures. If an
abnormal condition is detected, the LevelCom 100 will display the appropriate error message
on the digital display and activate an alarm to alert the operator.
The LevelCom 100 is contained in a water-resistant enclosure fabricated of .090" 5052 H32
aluminum alloy.
The following are definitions and explanations of LevelCom 100 features and the terminology
used in this manual and the LevelCom 100 configuration interface.
Alarm Setpoint: A user defined reference point that establishes the depth at which a
particular alarm will activate.
Bubbler: A bubbler is a remote sensing liquid level gauge that operates by measuring the
pressure required to blow bubbles from the bottom of a pipe mounted in a tank. If the
specific gravity of the liquid is known, this pressure can be converted to depth of the end of
the pipe below the liquid surface.
Bubbler Pipe: This refers to the pipe installed in the tank and connected to the LevelCom
100. To sense depth the LevelCom 100 blows bubbles from the bottom of this pipe. The
Bubbler to Bottom parameter is the distance between the lower end of the bubbler pipe and
the bottom of the tank.
Buttons: The LevelCom 100 has a set of buttons built into the face plate. These are used
to enter the configuration information into the device, and to locally acknowledge alarm
conditions. In normal operation the buttons may be used to display alternate units, for
example changing from a depth default to read volume or weight. Also the current units may
be read.
Calibrate: The LevelCom 100 is shipped fully calibrated and while in operation automatically
performs a periodic “hardware zero”. Should the unit require field calibration please
reference the calibration procedure beginning on page 72.
Communication: The LevelCom 100 can be purchased with optional communication
interfaces that allow a group of LevelCom 100s to be networked to a central control or data
acquisition computer. These interfaces include RS-422/RS-485 using standard Modbus RTU
Protocol. The machine may also be equipped with interfaces for DeviceNet, or Profibus
communication networks.
Configuration: The LevelCom 100 program allows users to configure the unit to a wide
variety of situations. The unit is shipped with a default configuration and the user adjusts the
parameters to match his own requirements thereby establishing the machine configuration.
Demand: The user may configure the LevelCom 100 to perform sample and/or purge
functions on demand in lieu of automatic timed cycles. This feature is normally used in areas
where the quantity of compressed air is limited or in applications not requiring constant
monitoring.
Hardware Zero: The LevelCom 100 periodically checks the sensor for drift of the zero point
by measuring atmospheric pressure. This value is used to correct the raw pressure readings
from the bubbler pipe. In normal operation the LevelCom 100 automatically performs the
hardware zero at half hour intervals.
Horn: The LevelCom 100 is available with an optional piezoelectric horn for local alarm
indication. This provides a local alarm function, the ACK button is used to acknowledge
alarms and silence the horn.
Hot Menu: The hot menu is for use when the configuration will be password protected. It is
a configurable menu that allows certain parameters, like specific gravity, to be available to
operators who don’t have the password. This allows operators to change these parameters
as needed while protecting the rest of the configuration from tampering.
Hysteresis: A user-defined measurement between an Alarm Setpoint and the point the
alarm condition will automatically clear. For example, assume a tank has a Maximum Depth
of 10' 0”. The High Alarm Setpoint is 8' 0". High Hysteresis has been set at 0' 6". The level
in the tank must rise to 8' in order for the High Alarm to activate. The level must then drop to
7' 6" for the alarm to clear.
Latch: This is a function available in the Light and Horn output sections of the program.
Latch holds alarm outputs active, even if the alarm condition has cleared, until the user
presses the Acknowledge key.
Lights: Refers to the LevelCom 100 front panel Hi and Lo alarm and status LED indicators.
Local: The optional alarm relays can be configured for Local Acknowledge. In this case if
the relays are configured as alarm outputs the alarm output will clear when the ACK button is
pressed. Otherwise the relay will clear only when the alarm condition clears.
Menu: The LevelCom 100 configuration is organized as a series of menus. These menus
are organized to simplify the configuration process by grouping related parameters together.
The buttons on the machine front panel are used to navigate through the menus.
MENU button: The MENU button is the front panel button used to enter the LevelCom 100
configuration menus. The MENU button is also used to make selections and activate or
deactivate functions in the configuration. On older machines this button is labeled MODE.
Parameter: A parameter is a number used by the LevelCom 100 to calculate a display value
or to trigger an alarm. Parameters are set by the user to define the configuration of the
LevelCom 100. Maximum Depth and Bubbler to Bottom are parameters.
Password: The LevelCom 100 can be configured for password protection of the user’s
configuration. The password characters are the letters A-Z. As few as 1, and as many as 9
characters can be used in the password. The LevelCom 100 can be programmed with a Hot
Menu, which allows easy access to frequently used functions and parameters. The Hot
Menu is not password protected.
Programming: When used in this manual this refers to the setup and entry of the user
configuration into the LevelCom 100.
Purge: The LevelCom 100 periodically applies compressed air to the bubbler pipe to ensure
it is free of liquid. This purge can also help keep the end of the bubbler pipe clear of
obstructions. The LevelCom 100 program can be configured to purge the bubbler pipe on
demand or at set times. The length of time allowed for a purge is adjustable from 5-120
seconds.
Relays: The LevelCom 100 is available with 2 optional “Form C” relays. These relays can
be used for alarm or control purposes.
Sense Line: The sense line is the system including the bubbler pipe mounted inside the
tank and the interconnecting tubing leading back to the LevelCom 100. The LevelCom 100
measures the pressure on this tube to calculate the depth of the liquid in the tank.
Specific Gravity: Specific gravity is a user-defined parameter in the program. This
parameter is used to convert the static pressure reading from the bubbler pipe into a depth
reading. Automatic Specific Gravity sensing is available as an option. If the LevelCom 100
is being used to monitor a tank that is used for various products with differing specific
gravities then we encourage the user to consider adding this option.
SURE? “SURE?” appears when the user has entered a section of the program that will
erase or overwrite the configuration. The LevelCom 100 queries the user to allow time for
the user to consider if he is certain of his actions. If “SURE?” appears on the display at any
point in programming and you do not know why - Don’t press ENTER!
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Digital Display Messages
The LevelCom 100 is designed to detect certain system problems and render messages on
the digital display. Following is a list of messages, which could be displayed by the
LevelCom 100. If an error message occurs refer to the trouble-shooting guide.
LEAK 1: The LevelCom 100 has determined the sense line is leaking. It must be noted the
LevelCom 100 will not detect a major, catastrophic failure of the sense line. In this event the
LevelCom 100 will sense the ambient atmospheric pressure, calculate that the tank is empty
and display the down arrow symbol indicating the level in the tank is below the end of the
bubbler pipe.
CAN’T ZERO SENSOR: Error message indicating the LevelCom 100 pressure sensor has
experienced a problem during a hardware zero measurement. The hardware zero measured
is outside the allowable range and the machine may need calibration or repair. The machine
will halt operation when this condition occurs, relays will go to their system fail state, and the
System Trouble light on the front panel will be lit.
CHECK AIR: Indicates the LevelCom 100 has detected either insufficient or excessive
supply air pressure. Confirm the air source is operating at the proper pressure and is
available to the instrument (refer to the specifications page 2). Check for contamination of
the air supply, e.g., water accumulations, plugged filters, debris blockages, etc.
Flashing Numeric Display: The numeric display will flash if the LevelCom 100 has sensed
a change in level and automatic sampling is not enabled. The instrument is indicating that
the displayed data may no longer be correct. Pressing the UP or DOWN key will cause the
unit to sample and display the new reading.
OVER PRESSURE: Indicates the LevelCom 100 is measuring an abnormally high pressure
on the sense line. The LevelCom 100 will activate the System Trouble alarm indicator and
test the sense line every 30 seconds to see if the condition has cleared. This fault condition
will clear when the sense line pressure returns to the allowable range.
Up Arrow or Down Arrow: To indicate an out
of range reading the digital display will show
flashing arrow symbols in the left most
character of the digital display. When the liquid
level falls below the end of the bubbler pipe the
machine will display the Bubbler to Bottom
Volume Overfill Example
value with a flashing down arrow to indicate that
the fluid level can no longer be measured. If
the fluid level is above the Maximum Depth
level the left most character will have a flashing
up arrow to indicate that the fluid level is over
the top of the tank.
SURE? SURE? appears when the user has entered a section of the program that will erase
or overwrite the configuration. The LevelCom 100 queries the user to allow time for the user
to consider if he is certain of his actions. If SURE? appears on the display at any point in
programming and you do not know why - Don’t press ENTER!
WAIT: Appears when a new reading has been manually requested, as in Flashing Numeric
Display above. A new reading is requested by pressing the Up or Down button. When the
new reading is complete the display will return to normal showing the new reading.
Lights
On the machine front panel there are individual LED lights to indicate alarm and fault
conditions.
The High Alarm and Low Alarm lights are used to indicate existing alarm conditions. There
are four possible alarm setpoints available on the machine, High High, High, Low, and Low
Low alarm. High and High High alarm conditions are indicated by the High alarm light. Low
and Low Low alarm conditions are indicated by the Low Alarm light. When an alarm
condition occurs, the respective alarm light will flash to indicate the alarm. If the ACK button
is pressed to acknowledge the alarm, the light will quit flashing and remain lit until the alarm
condition clears.
The TROUBLE light indicates fault conditions, such as a plugged sense line, low supply air
pressure, or leaking sense line system. When the condition occurs, the TROUBLE light will
flash to indicate the condition. If the ACK button is pressed to acknowledge the fault, the light
will quit flashing and remain lit until the fault condition clears, or another fault condition
occurs.
The ULLAGE light is lit to indicate that the current value shown on the digital display is an
ullage value, indicating how much of the tank remains to be filled. Typically an ullage reading
will indicate 0 for a full tank, and the maximum value for an empty tank.
Buttons
The front panel buttons are used in normal operation to view the display units, to switch
temporarily to different display units, to locally acknowledge alarms, and to manually trigger a
new reading.
To view the present display units, press the SHOW UNITS button. While the button is
pressed the current display units will be shown in text on the digital display, “FEET” for
instance.
The machine may be configured with more than one display unit. For instance it might be
desired to display depth as FEET, but it is also desired to display the Volume, in BARRELS.
In normal operation the machine will display depth information. Press the ALTERNATE
UNITS button to display the volume information. The new unit name will be shown briefly on
the digital display, BARRELS in this example, and the display will then display the volume
information. The display will switch back to the default units automatically after about 30
seconds, or it may be switched back by pressing the ALTERNATE UNITS button again.
To acknowledge alarm and fault conditions, press the ACK button. If an alarm light is
flashing to indicate a new alarm condition, the light will stop flashing and remain lit after the
ACK button has been pressed.
The machine is configured to sample the sense line regularly. It can be configured to
automatically sample the sense line when a change in depth is detected as well. To
conserve air it might be desired to have the machine sample infrequently, and not
automatically sample on a change of depth. You can manually trigger a sample any time by
pressing the UP or DOWN button while the machine is in normal operation. The display will
show the text message WAIT until the new sample operation is complete. Then the machine
will display the new reading.
Bubbler pipes are mounted inside the tanks,
and are the part of the sensing system in direct
contact with the measured liquid. When a
LevelCom 100 is replacing an older bubbler
gauge, the bubbler pipes and interconnecting
tubing need to be checked for leaks and plugs.
Otherwise there should be no concerns about
mounting and design of the sensing system.
NOTE:
The bubbler pipe is the key component in a
bubbler type level sensing system. Mounting
the bubbler pipe in the tank is critical to the
long term operation of the level measuring
system.
TUBING TO
LevelCom
In new installations it is important that the
bubbler system is correctly designed and
installed. This section will describe various
1/2" - 1 1/2" PIPE
bubbler pipe designs and other factors that
must be considered to arrive at a system that
operates correctly and provides reliable long
lasting service.
Figure 4 shows a typical in tank installation.
Note that the bubbler pipe is well supported
BUBBLER TO BOTTOM
and is installed to gauge the deepest part of
the tank. The interconnecting tubing is run to a
Figure 4 Typical Bubbler Pipe
point higher than the maximum height of the
tank to prevent siphoning of fluids in case the
tubing is disconnected from the LevelCom 100.
Size considerations
The diameter of the bubbler pipe will have effects on the system performance. The minimum
diameter for a bubbler pipe is ½ inch. The size range for bubbler pipes is typically from ½ to
1-1/2 inches. A smaller diameter bubbler pipe is more sensitive to leaks in the sensing
system and may be prone to plugging. Leaks will always cause errors in reading. The
smaller the bubbler pipe, the greater the errors due to leaks.
The too large bubbler presents a different set of
concerns. The LevelCom 100 admits measured
charges of air into the sense line system and
TUBING TO
LevelCom
each charge of air will displace the fluid in the
bubbler pipe by a certain amount. If the bubbler
pipe diameter is too large, it is possible that the
measured charges of air will not displace the
fluid in the bubbler pipe far enough to detect a
good reading. In this case the LevelCom 100
will not be able to detect when bubbles are
being blown from the end of the tank, and this
can result in significant reading errors.
Maximum diameter for a bubbler pipe should
not exceed 1.5 inches.
In tanks where there is agitation, mechanical
properties along with the diameter of the
bubbler pipe need to be considered. Agitation
and significant sloshing of the liquid will require
more mechanical strength in both the pipe and
mounting system. This is an especially
important factor to consider, when the pipe is
mounted to a flange at the top of the tank and
has no other support. Figure 5 shows a typical
flange mount installation. Note that the pipe is
only supported at the top.
Materials
It is important that the bubbler pipe be made of
materials compatible with the liquid to be
measured. Deterioration of the bubbler pipe will
result in measurement errors and eventually
failure of the sensing system.
For example if the LevelCom 100 is gauging a
Figure 5 Flange Mounting Example
ship’s ballast tank and will be exposed to salt
water, steel pipe will eventually corrode from constant exposure to salt water and should not
be used. In tanks containing acids or corrosives plastic pipe may be a better option.
It is always important to consider the strength of the materials used for the bubbler pipe.
When using plastic pipe, for instance, it would be better to use thick wall pipe (Schedule 40
or 80 for example) rather than thin wall pipe for mechanical strength.
mounting bubbler pipes in tanks. If the tank is
agitated with a mechanical stirring device, or the
liquid is subject to sloshing the bubbler pipe
supports will have to be strong enough to
maintain the integrity of the bubbler pipe.
The opening of the bubbler pipe should be as
near the lowest point of the tank as possible,
however there must be adequate clearance so
that any sludge that might build up in the tank
does not cause blockage of the bubbler pipe. 3
to 6 inch separation from the bottom of the tank
is common for bubbler installations. This
separation is called Bubbler to Bottom in the
configuration interface.
Onboard Tanks may have quite complicated
shapes and the placement of the bubbler pipe
deserves careful consideration. The bubbler
pipe should be mounted so that the opening of
the pipe is near the centerline of the tank. This
will help minimize the effects of side to side trim
in the ship. Fore and aft trim has some effect,
but for strength reasons the bubbler pipe is
usually mounted to the forward or aft bulkhead
of the tank.
Usually the bubbler pipe is mounted through the
top of the tank. This makes sure that the top of
the bubbler pipe is above the top of the tank, to
prevent any siphon action if the LevelCom 100 is
removed from the system for service. In shorter
tanks, up to about 10 feet in depth the bubbler
Figure 6 Side Entry Example
pipe can be mounted to a flange in the top of the
tank (Figure 5). In this case there would be no further supports for the bubbler pipe inside
the tank. Again, if the tank is agitated, or if the liquid can slosh with any force, the bubbler
pipe must be made of materials strong enough to withstand this liquid movement.
In taller tanks the bubbler pipe needs to be supported with standoffs fitted to the inside wall of
the tank. Make sure there are enough supports to maintain the strength of the bubbler pipe.
Figure 4 shows such standoffs and supports.
Side Mount Installation, is sometimes required
when tank top access is not possible. Figure 6 shows this kind of installation. If there is a
flange and cover on the side of the tank, the
bubbler pipe could enter through this flange.
This may simplify the mounting of the bubbler
pipe in the tank.
For this type of installation, it is important that
the interconnecting tubing run upward to a
point above the top of the tank and then back
down to the LevelCom 100. This is necessary
to prevent liquid from siphoning to the
interconnecting tubing system if the LevelCom
100 must be removed from the system for
service.
Specific Gravity
TUBING TO
LevelCom
A LevelCom 100 with the automatic specific
gravity option needs a second bubbler pipe in
the tank. The second pipe should be shorter
than the main bubbler pipe. Figure 7 shows a
typical specific gravity installation. The ends
E
C
N
A
T
S
I
D
.
G
.
S
of the two bubbler pipes need to be a known
vertical distance apart. The two bubbler pipes
should also be mounted so that the bottom
ends of the pipes are in the same vertical line.
This will minimize any errors caused by side to
side trim changes in the ship.
With the specific gravity option, the LevelCom
100 will take separate measurements on each
Figure 7 Specific Gravity Example
of the two bubbler pipes. Using the known
distance between the ends of the bubbler pipes, the two pressure readings can be used to
calculate the specific gravity of the fluid. This kind of installation is useful where the specific
gravity of the fluid in the tank is variable.
End Bell and Cleanout Options
Figure 8 shows examples of an end bell for
the bottom of the bubbler pipe and a type of
cleanout.
CLEAN-OUT
It is possible to decrease the system
sensitivity to leaks by putting a larger
diameter “bell” on the bottom of the bubbler
pipe. Also when the liquid level increases
END BE L L
OPTIONAL
some liquid will back up into the bubbler pipe.
The bell will minimize the amount of fluid that
Figure 8 End Bell and Clean Out Examples
will be displaced up the bubbler pipe before
the next LevelCom 100 sample operation.
If the liquid contains suspended solids that can deposit on the tank surfaces there should be
provision made for manual cleaning of the bubbler pipe. In the example shown the tubing
from the LevelCom 100 enters the bubbler pipe through a T fitting. A ball valve in line with
the bubbler pipe allows a cleaning rod to be inserted into the bubbler pipe to remove any built
up material from the liquid. This valve is shut in normal operation. This valve is a potential
source of leaks so this option should only be used where necessary.
Interconnecting Tubing
The tubing connecting the LevelCom 100 with the bubbler pipe can be either plastic or metal.
Copper tubing is very common, stainless steel and plastic tubing also work well. The
material chosen must be compatible with the installation environment.
If the length of the tubing run is greater than 80 feet the tubing should be 3/8 diameter,
otherwise ¼ inch tubing will work. The tubing needs to be properly supported, and protected
from damage. The tubing should not be larger than ½ inch to avoid having too large a
volume of air in the sensing system.
It is also important that the tubing should not have a low spot that can trap liquid. Any liquid
that enters the tubing will accumulate in such a low spot and will cause measurement errors
or false leak indications. If it is necessary to have such a low spot in the tubing then
provision should be made for clean out.
There are cases where the liquid contains a
large amount of suspended solids and there
will have to be provisions for cleaning out the
bubbler pipe. Some examples from actual
LevelCom 100 installations follow.
Drill Mud
LevelCom 100s can be used to gauge drill
mud for oil drilling operations. Drill mud is a
thick liquid full of finely ground clay and
emulsifiers to keep the clay suspended in the
liquid. Solids will build up at any liquid air
interface including the end of the bubbler
pipe. The bubbler pipe needs some provision
CLEAN-OUT
for routine cleaning to prevent plugging over
time. Figure 9 shows an example of this kind
of installation. The bubbler pipes are
installed through the sides of the tanks at a
45 degree angle. The angled bubbler pipe is
fitted with a large ball valve which can be
opened to allow a clean out rod to be pushed
CLEAN-OUT
through to remove mud solids buildup from
the inside of the bubbler pipe. This operation
would be done only when the tank is empty.
Slurries and Viscous Liquids
LevelCom 100s have been used to gauge
mix tanks for hot asphalt and calcium
carbonate primarily to measure the specific
Figure 9 Drill Mud Tank Cleanout Example
gravity of the mix. The mixtures will build up
on the bubbler pipes, so the pipes were mounted to a plate that could be removed from the
system for cleaning. This operation was part of the regular scheduled daily or weekly system
maintenance.
The LevelCom 100 has been designed to be mechanically rugged, accurate and dependable.
It is best to select a mounting location that is as clean as possible and well protected against
adverse environments. The LevelCom 100 enclosure is UL listed as “Rain tight for indoor
use”. Avoid areas of high moisture and temperature, excessive vibration and concentrated
electrical interference. Good lighting is helpful but not essential since the LevelCom 100
display is brightly lit. Consider access for electrical connections to the top and pneumatic
tubing to the bottom of the LevelCom 100.
If you are replacing an existing device, you may have an opportunity to improve on the
original mounting location. Study the area to see if another site might be better suited. It is
best to have a dedicated power supply for the LevelCom 100, that is, one with its own circuit
protection device (fuse or circuit breaker).
Mounting Preparation
For access to electrical connections, the LevelCom 100 is designed with two 0.875” holes in
each side of the case intended for ½” electrical fittings. Use fittings in accordance with the
NEC which are suitable for the wiring system and suitable to maintain the UL “Rain tight”
rating of the enclosure.
Surface Mounting
The LevelCom 100 normally comes equipped with two stainless steel mounting brackets
attached to the box. Using the mounting holes in these brackets the LevelCom 100 is
mounted to the surface using #10 screws. The spacing of the bracket mounting holes is 4”
horizontal by 14.75” vertical. This is the most common way of mounting LevelCom 100s.
Many installations require multiple LevelCom 100s to be mounted in close proximity to one
another. The LevelCom 100s should be mounted side by side all at the same level. The
LevelCom 100 is exactly 5.5” wide so a 6” center from unit to unit is recommended. A 6”
mounting center will afford 0.5” clearance between units. This clearance will allow easier
access to mounting hardware should it become necessary to remove one unit from the
installation. Figure 10 shows a typical panel with three LevelCom 100s mounted side by
side. The relevant dimensions are shown for reference.
Note that each LevelCom 100 has an individual drain tube. In the example the drain tubes
angle through the plate and exhaust behind the plate. This keeps any expelled liquid away
from the front of the plate keeping the installation clean.
Use the LevelCom 100 Interconnect Kit to create a wiring path between machines. See
Figure 11 for drawings and description of the interconnect kit. The result is a clean efficient
installation.
The LevelCom Interconnect Kit is pictured
in Figure 11. Each kit contains the
following:
2 each - 2.5” x ½” plastic conduit
4 each - Rubber Grommets
These kits are recommended for
LEVELCOM SPACING
CENTER TO CENTER
installation of several LevelCom 100s
side-by-side as shown in Figure 10. The
kits provide a continuous, moisture-proof
wiring path between units. The LevelCom
100s are typically mounted at 0.5”
spacing. This puts the boxes on 6 inch
centers as shown in Figure 11.
Mount the grommets in the holes in the
sides of the LevelCom 100 boxes. The
interconnecting tubes are installed after
the boxes have been mounted.
Flush mounting is accomplished with the
optional flush mount kit, which includes 2
stainless steel brackets, 4 - #10-32 x ½” screws and 4
- #10-32 x 1” pointed screws. The flush
mounting brackets replace the surface
mounting feet normally provided with the
LevelCom 100.
Figure 12 shows the Flush Mounting brackets and
how they are used to mount the LevelCom 100. Cut a
4.75” by 13.5” opening in the mounting surface. Pass
the LevelCom 100 through this hole from the front
of the panel and then mount the brackets to the rear
of the case with the short screws. Insert the
pointed screws into the threaded holes in the
brackets from the rear, and snug them evenly
against the back of the mounting surface. Do not
over tighten the long screws, since this may
distort the mounting brackets.
Depending upon options ordered there are
five possible locations for electrical
connections in the LevelCom 100. 115 Volt
AC power wiring should be separated from
any signal or low-voltage control wiring.
Generally the 115 Volt AC wires would utilize
the upper conduit, and signal or low-voltage
wiring, if any, would use the lower conduit.
Secure wires with plastic cable ties to the
strain relief plate at the top of the enclosure
above the main controller circuit board.
115VAC
115 VAC connections are made via the threepoint connector labeled AC POWER at the
top center of the circuit board (See Figure
13). The three-point connector is actually a
plug and socket. Grasp the plug firmly and
pull it off the board. Note the printing on the
circuit board above the socket, which reads
[GND] [L1] [L2].
Note the enclosure ground “GND” stud
located on the inside of the enclosure,
immediately to the right of the 3 capacitors on
the main CPU board. This stud should be
wired to ground; it is intended as a protective
earth connection. There is not adequate
connection between the circuit boards and
the case to insure a proper case protective
ground.
The LevelCom 100 power switch is located to
the left of the 115 VAC connector. Power ON
is the up position (closest to the edge of the board).
It is important to segregate low voltage wiring, typically 24VDC from the high voltage wiring.
Power wiring is usually 115 VAC. If the optional Relay Module is installed it is possible that
wiring to the relays is also 115 VAC. This must be verified before wiring the unit. Low
voltage wiring and high voltage wiring should enter the LevelCom 100 through separate
strain reliefs, possibly from opposite sides of the box. Figure 14 shows how this might be
done for a pair of LevelCom 100s mounted on a panel. The interconnect kit is used to
establish a wiring path between the two boxes. In this example there is power wiring and
communication wiring. The power wiring uses the upper wireway, and is banded to the strain
relief plate. The wires to the main power connectors arch over the communication wire
bundle. The communication wiring uses the lower wireway and is banded to the strain relief
plate.
24VDC
If your machine is built with the 24VDC input power option the 24VDC power connections are
made via the three-point connector labeled AC POWER at the top center of the circuit board
(See Figure 13). In place of the transformer on the controller circuit board there will be a
small circuit board with a DC to DC converter. There is a label on this circuit board
describing the wiring for this option. Note that the GND connection is for system ground and
not the 24V power supply return.
The optional Analog Output is a 420 mA current type. The output
may be internally powered, or
isolated and powered from an
external source, by changing three
circuit board jumpers. External
supply voltage may be up to 48
VDC. The jumpers are located on
the Sensor Input Circuit Board,
Figure 15 Jumper Settings for -A1 and -A3
(LC100-A1, -A2, -A3). This board
is the larger circuit board mounted
to the Controller board (Figure 13).
In the upper right-hand corner of
the Sensor Input Circuit Board are
three jumpers that have been
mounted onto pin headers, note the
Figure 16 Jumper Settings for LC100-A2 Board
labels ISOLATE and POWER
printed above and below the jumpers. You must identify the revision of Analog Circuit Board
in your machine; the jumper settings are different for different boards. You can read the
board type at the left edge of the Analog Circuit board (Figure 13). Figure 15 and Figure 16
show the jumper positions for the different board types. Move the jumpers as required.
Note: Failure to switch jumpers may cause damage to the circuit board.
The Analog Output connector is located at the top right of the main circuit board adjacent to
the Analog Input connector (Figure 13). The connector is a plug and socket. Pull the plug
out of the socket for ease in making up the connections. Be sure to observe polarity
markings.
Relay Output
Since the Relay Output is an option, this connector may not have been installed in your
LevelCom 100. If this option has been selected, the six-point connector can be found at the
right side of the LevelCom 100 enclosure centered horizontally on the Relay Module (Figure
13).
Note: When facing the relays Relay #1 is on the right, Relay #2 on the left.
The contacts are labeled for the relays in a de-energized state.
NC = Normally Closed
COM = Common
NO = Normally Open
The Relay Outputs are rated for “Pilot Duty”. Contacts are rated at 5A non-inductive, 115
VAC or 30 VDC. Maximum ratings are 250 VAC/125 VDC/150 W. It is not recommended
that these contacts be used to switch inductive loads. In cases where higher loads need to
be switched, an external slave relay rated for the higher current must be used. After wiring is
complete secure the conductors to the wiring support bracket using a cable tie.
Note: When used with 115VAC circuits, those circuits must be powered by an Overvoltage
Category II Power source.
RS-422/485 Serial Communication
Since Serial Communication is an option, this five-point connector may not have been
installed in your LevelCom 100. If this option has been selected, the connector can be found
toward the left side of the LevelCom enclosure on the Communications Module. The
connector is actually a plug and socket. Note the printing on the circuit board above the
socket which reads [RX-] [RX+] [TX-] [TX+] [GND].
The terminals are described below:
[RX-] Receive Data (- polarity), Connect to Computer [TX-] Transmit Data (- polarity)
[RX+] Receive Data, (+ polarity) Connect to Computer [TX+] Transmit Data, (+ polarity)
[TX-] Transmit Data, (- polarity) Connect to Computer [RX-] Receive Data, (- polarity)
[TX+] Transmit Data, (+ polarity) Connect to Computer [RX+] Receive Data, (+ polarity)
[GND] Common Connect to Computer Common
Use cable designed for RS-422/485 communications. These cables are usually shielded
twisted pairs with a characteristic impedance of 120 ohms. If the system is using separate
transmit and receive channels you will need two pairs. Otherwise a single twisted pair is
needed. Cable runs can be up to 4000 feet long. The LevelCom 100 can be configured to
communicate using the Modbus RTU protocol. The baud rate and parity are configurable.
Up to 64 LevelCom 100’s can be paralleled on one communication cable.
Use cable specified for RS-422/485 for these connections.