Magnetrol STI Echotel 338 User manual

Installation and Operating Manual
Two-Wire Non-Contact
Ultrasonic Transmitter
For Level, Volume,
and Open Channel Flow
Measurement
Echotel®Model 338

Read this Manual Before Installing
This manual provides information on the Echotel Model
338 Two-Wire Non-Contact Ultrasonic Transmitter. It is
important that all instructions are read carefully and
followed in sequence. Detailed instructions are included
in the Installation section of this manual.
Conventions Used in this Manual
Certain conventions are used in this manual to convey
specific types of information. General technical material,
support data, and safety information are presented in
narrative form. The following styles are used for notes,
cautions, and warnings.
Notes
Notes contain information that augments or clarifies
an operating step. Notes do not normally contain
actions. They follow the procedural steps to which
they refer.
Cautions
Cautions alert the technician to special conditions that
could injure personnel, damage equipment, or reduce
a component’s mechanical integrity. Cautions are also
used to alert the technician to unsafe practices or the
need for special protective equipment or specific mate-
rials. In this manual, a caution box indicates a poten-
tially hazardous situation which, if not avoided, may
result in minor or moderate injury.
Warnings
Warnings identify potentially dangerous situations or
serious hazards. In this manual, a warning indicates an
imminently hazardous situation which, if not avoided,
could result in serious injury or death.
Safety Messages
Follow all standard industry procedures for servicing elec-
trical equipment when working with or around high
voltage. Always shut off the power supply before touching
any components.
WARNING! Explosion hazard. Do not connect or
disconnect equipment unless power has been switched off
or the area is known to be non-hazardous.
Low Voltage Directive
For use in Installation Category II, Pollution Degree 2.
If equipment is used in a manner not specified by the
manufacturer, protection provided by the equipment
may be impaired.
Notice of Trademark, Copyright, and Limitations
Echotel is a registered trademark of Magnetrol
International.
Copyright © 2003 Magnetrol International.
All rights reserved.
Magnetrol reserves the right to make changes to the prod-
uct described in this manual at any time without notice.
Magnetrol makes no warranty with respect to the accuracy
of the information in this manual.
Warranty
All Magnetrol/STI electronic level and flow controls are
warranted free of defects in materials or workmanship for
one full year from the date of original factory shipment.
If returned within the warranty period; and, upon factory
inspection of the control, the cause of the claim is deter-
mined to be covered under the warranty; then,
Magnetrol/STI will repair or replace the control at no cost
to the purchaser (or owner) other than transportation.
Magnetrol/STI shall not be liable for misapplication,
labor claims, direct or consequential damage or expense
arising from the installation or use of equipment. There
are no other warranties expressed or implied, except spe-
cial written warranties covering some Magnetrol/STI
products.
Quality Assurance
The quality assurance system in place
at Magnetrol guarantees the highest
level of quality throughout the com-
pany. Magnetrol is committed to pro-
viding full customer satisfaction both
in quality products and quality service.
Magnetrol’s Corporate quality assurance system is regis-
tered to ISO 9001 affirming its commitment to known
international quality standards providing the strongest
assurance of product/service quality available.

Table of Contents
1.0 Installation
1.1 Unpacking ...............................................................1
1.2 Mounting and Application Considerations ..............1
1.2.1 Position........................................................1
1.2.2 Orientation..................................................1
1.2.3 Temperature.................................................1
1.2.4 Obstructions ................................................2
1.2.5 Standpipes....................................................2
1.2.6 Foam............................................................2
1.2.7 Vapors..........................................................2
1.2.8 Wind ...........................................................2
1.2.9 Open Channel Flow Measurement ..............2
1.3 Electrostatic Discharge (ESD) Handling Procedure..3
1.4 Wiring .....................................................................3
1.5 Configuration ..........................................................4
1.5.1 LCD Module ...............................................4
1.5.2 QuickSet Configuration.................................6
1.5.3 Basic Functions............................................7
1.5.4 Setting QuickSet Configuration Parameters ...7
1.6 Complete Configuration..........................................9
1.6.1 Measurement Configuration Parameters ....10
1.6.2 mA Current Output Settings .....................15
1.6.3 Performance Enhancement ........................16
1.6.4 Volume Configuration ...............................20
1.6.5 Open Channel Flow Configuration ...........21
1.6.6 Linearization Table.....................................25
1.6.7 Information Parameters..............................26
1.6.8 Open Channel Flow Head and Totalizers ..28
1.6.9 Output Test Parameters..............................28
1.6.10 Simulation Mode .......................................29
1.6.11 Additional Software Parameters..................30
1.7 Configuration without LCD Module.....................31
1.7.1 Minimum Level/Empty Tank
(4 mA setpoint)...........................................32
1.7.2 Maximum Level/Full Tank
(20 mA setpoint).........................................32
1.7.3 Fail-safe Indication by the mA
Current Output ..........................................33
1.7.4 Damping Time............................................33
1.7.5 Factory Data Reset ......................................33
1.7.6 Programmng Error Indications during
Programming by LEDs ...............................34
1.8 Diagnostic Error Codes..........................................34
2.0 Reference Information
2.1 Description ............................................................35
2.2 Theory of Operation..............................................35
2.3 Performance...........................................................35
2.4 Measurement Range Calculations ..........................36
2.5 Velocity of Sound in Gases other than Air .............37
2.6 Specifications .........................................................37
2.6.1 Performance ................................................37
2.6.2 Transmitter..................................................38
2.6.3 Transducer ..................................................38
2.6.4 Physical .......................................................39
2.7 Model Number......................................................39
2.8 Configuration Parameter Worksheet ......................40
Echotel Model 338
Non-Contact Ultrasonic Transmitters
51-638 Echotel Model 338 Two-Wire Ultrasonic Transmitter

151-638 Echotel Model 338 Two-Wire Ultrasonic Transmitter
1.0 Installation
Caution: If equipment is used in a manner not specified by manufac-
turer, protection provided by equipment may be impaired.
1.1 Unpacking
Unpack the instrument carefully. Inspect all units for
damage. Report any concealed damage to carrier within
24 hours. Check the contents of the packing slip and
purchase order. Check and record the serial number for
future reference when ordering parts.
Caution: Do not discard the shipping container until all parts are
checked.
1.2 Mounting and Application Considerations
Caution: Unit should only be hand-tightened into the process con-
nection. The wrench flats should only be used when
removing the unit. Overtightening will cause transducer
errors and will void the warranty.
There are several application considerations that should be
evaluated prior to installing a non-contact ultrasonic trans-
mitter. The next few pages should be read thoroughly to
ensure that the Model 338 will perform as expected in
the given application. Section 2.4, Measurement Range
Calculations, provides measurement range calculations that
should be used to determine the maximum potential range
in difficult applications.
1.2.1 Position
The optimum mounting position of the Model 338 is
between 1⁄2of the radius and 2⁄3diameter of the (cylindrical)
tank. This will position the unit to minimize any interfer-
ence that the 5° beam (2.5° half angle) has with the tank
walls or any agitator blades that exist in the tank. Refer to
beam angle figure on page 35.
1.2.2 Orientation
The face of the transducer must be parallel to the liquid
surface within ±2° to 3°.
1.2.3 Temperature
Ensure that the transmitter will be protected against
overheating by direct sunshine. When the unit will be
subjected to severe direct sun, the use of a sunshade is
recommended.
Sunshade

51-638 Echotel Model 338 Two-Wire Ultrasonic Transmitter 2
1.2.4 Obstructions
Ensure that no obstacles (e.g. fill pipes, ladders, bracing
members, thermometers, etc) protrude into the ultrasonic
beam. Even though one fixed object in the tank can be
blocked out by appropriate programming, it is advised to
avoid these obstructions.
1.2.5 Standpipes
In applications where the material level may come into the
dead zone, the transducer must be mounted in a stand-
pipe. Refer to Section 1.6.1, Measurement Configuration
Parameters, P05: Dead Zone for dead zone value. The inner
rim of the standpipe must be smooth and free of burrs.
The minimum diameter for a given length of standpipe is
shown at left.
1.2.6 Foam
Foaming of the liquid surface may render ultrasonic level
measurement impossible. If possible, a mounting location
should be found where foaming is at a minimum. Another
alternative is to install the transducer in a stilling well that
extends below the lowest level to be measured in the tank.
1.2.7 Vapors
Closed tanks that contain chemicals or other liquids that
create vapors may severely reduce the maximum measuring
range. Refer to the Section 2.4, Measurement Range
Calculations for more information.
1.2.8 Wind
Intensive moving of the air in the vicinity of the ultrasonic
beam is to be avoided. A strong wind may not allow the
return echo to be received by the ultrasonic transducer.
1.2.9 Open channel flow measurement
For the best accuracy, install the transducer as close as pos-
sible above the expected maximum water level in the flume
or weir.
Install the Model 338 upstream of the flume throat or weir
crest in the location defined by the manufacturer of the
primary measuring device. The unit should also be aligned
with the longitudinal axis of the flume or weir.
Diameter
Length
Standpipe Length Minimum Diameter
6" (150 mm) 3" (75 mm)
8" (200 mm) 3" (75 mm)
10" (250 mm) 4" (100 mm)
12" (300 mm) 4" (100 mm)
14" (350 mm) 5" (125 mm)

1.3 Electrostatic Discharge (ESD) Handling
Procedure
Magnetrol’s electronic instruments are manufactured to the
highest quality standards. These instruments use electronic
components that may be damaged by static electricity pres-
ent in most work environments. The following steps are
recommended to reduce the risk of component failure due
to electrostatic discharge.
Ship and store circuit boards in anti-static bags. If an anti-
static bag is not available, wrap the board in aluminum
foil. Do not place boards on foam packing materials.
Use a grounding wrist strap when installing and removing
circuit boards. A grounded workstation is recommended.
Handle circuit boards only by the edges. Do not touch
components or connector pins.
Make sure that all electrical connections are completely
made and none are partial or floating. Ground all equip-
ment to a good, earth ground.
1.4 Wiring
Caution: Power must be switched off before wiring the unit.
OBSERVE ALL APPLICABLE ELECTRICAL CODES AND
PROPER WIRING PROCEDURES.
1. Unscrew and remove the cover of the unit. Remove the
LCD module to access the 4-position terminal block.
2. The two wires are connected to the 4-position removable
terminal block with negative at position #2 and positive at
position #3.
Caution: Terminal block must be removed with needle nose pliers.
Forcing it out with a screwdriver will cause damage to
the mating pins and void the warranty.
3. The unit must be grounded either by the inner or outer
grounding screw. The inner ground screw is located imme-
diately below the 4-position removable terminal block. For
practical purposes, most units are grounded using the
outer ground screw.
4. After wiring is complete the cable entries should be
properly sealed to maintain the NEMA 6 (IP 67) rating.
NOTE: A loop current check is most easily accomplished by pushing
the lower right button (down arrow) and viewing the LCD display.
Alternatively, a meter can be connected to position #1 (negative)
and position #4 (positive) to check the loop value.
351-638 Echotel Model 338 Two-Wire Ultrasonic Transmitter

CAUTION 


SENSITIVE ELECTRONIC DEVICES
DO NOT SHIP OR STORE NEAR STRONG
ELECTROSTATIC, ELECTROMAGNETIC,
MAGNETIC, OR RADIOACTIVE FIELDS
Display Socket 4-position
Terminal Block
Pg16 Pg16
Grounding
1/2"
NPT 1/2"
NPT
Red (+)
Black (–)
4-position
Terminal Block
Red (+)
Black (–)
12 34

1.5 Configuration
There are two methods of configuring the Echotel Model
338 transmitter:
1. Using the four push buttons and the plug-in LCD module
to perform either the QuickSet or the Complete
Configuration (see below).
2. Using the four push buttons while checking the status of
the COM and ECHO LED’s. Refer to Section 1.7,
Configuration Without LCD Module.
1.5.1 LCD Module
The LCD module can be used to set any of the configura-
tion parameters used with the 338 transmitter. The LCD
module can also be removed from the transmitter to con-
figure other 338 transmitters, or as a precautionary meas-
ure to avoid unauthorized changes to the configuration
data. It is not necessary to power down the 338 prior to
removing or replacing the LCD module. The 338 is fully
functional without the plug-in LCD module.
The LCD module consists of a bar graph that indicates
echo strength or level as a percentage of span, and a cus-
tom graphics display that shows all configuration, meas-
urement, and diagnostic data. The symbols at left are used
in the LCD module:
DIST =Distance from the face of the transducer to
the liquid surface
LEV =Level measurement from the bottom of
the vessel
VOL =Volume of liquid in the vessel
FLOW =Flow measurement in the flume or weir
PROG =Programming mode (transmitter is being
programmed)
T1 =Displays the volume in the resettable totalizer
T2 =Displays the volume in the non-resettable
totalizer
FAIL =Adiagnostic failure has been detected
=Indicates increasing level in the vessel
=Indicates decreasing level in the vessel
=Indicates stable level in the vessel
51-638 Echotel Model 338 Two-Wire Ultrasonic Transmitter 4

551-638 Echotel Model 338 Two-Wire Ultrasonic Transmitter
The middle row of the LCD module consists of a 6-digit
alphanumeric display of all data. Engineering units for the
numeric data are printed above and below the LCD. Two
pointers are used to indicate which units pertain to the
display that is currently being viewed. The pointer in the
upper right portion of the module indicates:
M=Metric (numbers displayed can be either cubic
meters, meters, cm, or liters)
US =US (numbers displayed can be either cubic feet,
feet, inches, or gallons)
Programming with the LCD module involves pressing one
or two (simultaneously) of the four push buttons. The
push buttons can also be used to access data while in the
normal operating mode as shown below.
Push button While Configuring Unit In Normal Mode
ENTER QuickSet Configuration: saves the displayed data Not used
and proceeds to the next parameter register
Complete Configuration: switches between the
parameter value and the parameter register
NEXT Shifts the blinking digit one position to the left Switches between measurement modes
(level, distance, volume, flow)
UP Used to increase the value of the blinking digit Displays the temperature reading
DOWN Used to decrease the value of the blinking digit Displays the current (mA) reading
There are two LEDs that can be used to make sure that
the 338 transmitter is functioning properly. The ECHO
LED will remain lit as long as the 338 is receiving a good
signal reflected back from the liquid surface. The COM
LED is for remote communications, and is not currently
used by the 338 transmitter.
LEV
UP
DOWN
NEXT
ENTER

51-638 Echotel Model 338 Two-Wire Ultrasonic Transmitter 6
1.5.2 QuickSet Configuration
NOTE: Configuration can only be done when the unit is receiving a
good return signal and the ECHO LED is lit.
Many level applications are easily set up by using the
QuickSet Configuration. Open channel flow, volume, or
more detailed level configuration is performed by using
Section 1.6, Complete Configuration. The following six
parameters can be set by using QuickSet:
1. Engineering units of feet or meters (other units can be
selected by using the Complete Configuration)
2. Range (maximum measuring distance)
3. 4 mA setpoint
4. 20 mA setpoint
5. Fail-safe indication of 3.6 mA, 22 mA, or "Hold"
6. Damping time of up to 60 seconds
The Model 338 is shipped with "Level" as the default for
the LCD, bargraph, and mA current output. The factory
default values for the QuickSet Configuration data are:
1. Engineering units of feet
2. Range of 20 feet
3. 4 mA set at 0 feet
4. 20 mA set at 19.17 feet (Range – 10" dead zone)
5. Fail-safe set for "Hold" last value
6. Damping time of 60 seconds
Holding the and buttons down at the same time
for 3 seconds allows entry into the QuickSet menu. The
instructions for entering or exiting QuickSet are also printed
on a label under the housing cover, just above the LCD
module.
LEV

751-638 Echotel Model 338 Two-Wire Ultrasonic Transmitter
1.5.3 Basic Functions
The commands below set the basic functions of the 338
transmitter during QuickSet Configuration.
Shown below are some additional commands that can
be used while in the QuickSet menu. The "Get Level"
command is especially useful if the level or distance is
unknown, and the liquid is at the proper height in
the tank.
1.5.4 Setting QuickSet Configuration Parameters
The table on page 8 shows how to set all six of the
QuickSet Configuration parameters.
NOTE: Current output can also be programmed for inverted
operation: 4 mA = 100% (Full), 20 mA = 0% (Empty)
NOTE: If a parameter value is not accepted by the LCD module, the
existing parameter value will keep blinking. This is due to:
1. The value is out of range (example would be trying to
enter a range value larger than 20.00 feet)
2. The parameter value is not valid for this screen
Pushbutton Keys Function
ENTER + DOWN Enter or exit QuickSet Configuration
(press for 3 seconds) menu
UP or DOWN Increase or decrease value of blinking
digit, or scroll up/down to change
parameters
NEXT Move the blinking digit to the left
(to change its value)
ENTER Saves the value currently being dis-
played and moves to the next QuickSet
parameter
Pushbutton Keys Function
UP + DOWN Accesses the "Get Level" screen to
(press for 3 seconds) display the actual measured level or
distance currently being measured by
the Model 338 transmitter
NEXT + UP Reset parameter back to the previously
saved value
NEXT + DOWN Reset the currently displayed parameter
back to the factory default value
LEV

Display Actions
Application
xx: Select "EU" (European) for metric or "US" for US engineering units by using UP / DOWN keys
Factory Default Value: US and LI
After selecting the desired value push the ENTER to save the value and proceed to the next parameter.
H: xxxx Range (maximum measuring distance)
Distance between transducer face and bottom of the tank.
Manual Entry: Set value using UP / DOWN / NEXT keys and save it with the ENTER key.
Automatic Entry: Use the "Get Level" function (UP + DOWN ) to obtain the actual measured value
in the tank, or to a fixed target, i.e. wall. Push ENTER to save value and proceed to the next parameter
Note: The "Get Level" feature only works if the Echo LED is lit.
Factory Default Value: 20 feet (maximum range)
4: xxxx Level value assigned to 4 mA current output
Manual Entry: Set level value using UP / DOWN / NEXT keys and save it with the ENTER key.
Automatic Entry: Use the "Get Level" function (UP + DOWN ) to display the actual measured value
with level in the tank or to a fixed target. Push ENTER to save value and proceed to the next parameter.
Note: The "Get Level" feature only works if the Echo LED is lit.
Factory Default Value: 0 feet (0% value or, empty tank)
20: xxxx Level value assigned to 20 mA current output
Manual Entry: Set level value using UP / DOWN / NEXT keys and save it with the ENTER key
Automatic Entry: Use the "Get Level" function (UP + DOWN ) to display the actual measured value
with level in the tank or to a fixed target. Push ENTER to save value and proceed to the next parameter.
Note: The "Get Level" feature only works if the Echo LED is lit.
Factory Default Value: 19.17 feet (100% full tank, this value is range minus the dead zone of 10")
Er is the fail-safe Error indication value.
Select "Hold", "3.6" mA or "22.0" mA by using the UP / DOWN keys, and push ENTER to
save the value and proceed to the next parameter.
Factory Default Value: "Hold" last mA current value
dt is the damping time (in seconds) required for the level application
Select 0, 3, 6, 10, 30, or 60 seconds by using the UP / DOWN keys) and push ENTER to save
it as above.
Factory Default Value: 60 seconds
51-638 Echotel Model 338 Two-Wire Ultrasonic Transmitter 8
NOTE: If no push buttons are pressed for 30 minutes, the transmitter
will automatically return to the measurement mode, and oper-
ate with the parameters entered during the last completed
programming.
NOTE: The Range, 4 mA, and 20 mA values shown below can be
entered manually, or by automatic entry using the "Get Level"
feature. Because the automatic entry involves moving the
liquid level to the exact 4 mA point, 20 mA point, and Range
values, the manual entry is the preferred configuration mode.
To enter or exit the QuickSet Configuration menu press
ENTER + DOWN keys for 3 seconds.
Ap:xxyy
H:xxxx
4:xxxx
20:xxxx
Er:xxxx
dt:xxxx

951-638 Echotel Model 338 Two-Wire Ultrasonic Transmitter
1.6 Complete Configuration
NOTE: Configuration can only be done when the unit is receiving a
good return signal and the ECHO LED is lit.
Open channel flow, volume, and more advanced level appli-
cations are configured using the Complete Configuration
Menu.
To enter (or exit from) this menu press the ENTER +
NEXT keys simultaneously for 3 seconds. While pro-
gramming the 338 in this menu, the display will indicate:
yy is the Parameter Register
xxxx is the Parameter Value
NOTE: While in the programming mode, the 338 will continue to
measure level based on pre-existing configuration parame-
ters. New configuration parameters will be used after exiting
the programming mode.
The following keystrokes can be used while programming
in the Complete Configuration Menu:
Keystrokes Action when Parameter Register is blinking Action when Parameter Value is blinking
ENTER + NEXT Enter or exit Complete Configuration Menu Nothing – Parameter Register must be blinking
(press for 3 seconds) to enter or exit the Complete Configuration menu
UP / DOWN Scroll up or down Parameter Registers Increase or decrease Parameter Value
ENTER Switches blinking digit to the Parameter Value Saves changes to the Parameter Value and
side of the display switches back to the Parameter Register side of
the display
NEXT Move blinking digit one position to the left Move blinking digit one position to the left
NEXT + UP Cancel programming changes made to all Cancel programming changes made to all
(press for 3 seconds) registers and revert back to previous parameter registers and revert back to previous parameter
values. Must press for 3 seconds until CANCEL values. Must press for 3 seconds until CANCEL
is displayed in LCD. is displayed in LCD.
NEXT + DOWN Resets entire unit back to the Factory Default Displays the default of the Parameter Value
Values. • Press ENTER to save the default value
Since this will reset all parameters, "LOAD" will • Press UP / DOWN to change to
appear on the display: another value
• Press ENTER to confirm this reset
• Press any other key to CANCEL and escape
The only exception is clearing TOT1 (Parameter P77)
yy:xxxx
LEV

aApplication Display Indication
0Liquid level measurement "Li"
51-638 Echotel Model 338 Two-Wire Ultrasonic Transmitter 10
1.6.1 Measurement Configuration Parameters
The following pages explain how to configure each param-
eter of the Complete Configuration. Since some Parameter
Registers are not used by the 338, several parameters are
skipped. Refer to Configuration Parameter Worksheet,
Section 2.8, for a complete listing of all parameters.
Many of the registers have multiple configurations within
the same register. For example, P00 below is used to select
Metric or US, the engineering units, and the application.
Since some registers only have one configuration ("a"), and
some have more than one, the digit order for each register
is d, c, b, a.
P00: - cba Application and Engineering Units
Factory default value for P00 is: 000
cMeasuring System
0Metric
1US
bEngineering Units (see "c")
English Metric
0feet meter
1inch cm
P01: - ba Bar Graph and Measurement Mode
Factory default value for P01 is: 11
The bar graph can be set at "0" to indicate the strength of
the return echo, or to "1" to indicate the mA current out-
put as a percentage of the span.
The Measurement Mode configures the 338 for the
desired application. If "0" is selected the only measure-
ment value that will be displayed is distance. Selecting
other values will allow distance, level, and volume or flow
measurements to be displayed alternatively by using the
NEXT key in the operating mode. The value of "a"
also determines the values of registers P40 through P48. If
"3" or "4" is selected these values will be volume parameters,
and if "5" is selected these values will be flow parameters.

11 51-638 Echotel Model 338 Two-Wire Ultrasonic Transmitter
NOTE: Tank or flume/weir dimensions must be entered prior to dis-
playing volume or open channel flow values. Programming for
these parameters begins with P40.
bBar Graph Indication
0Echo strength
1Current output
aMeasurement Mode Displayed Measurements
0Distance DIST
1Level LEV, DIST
2Level in percentage LEV%, LEV, DIST
3Volume VOL, LEV, DIST
4Volume in percentage VOL%, VOL, LEV, DIST
5FlowFLOW, T1, T2, LEV, DIST
P02: - cba Calculation Units
Factory default value for P02 is: 000
Engineering units for volume are selected in "b", and units
for open channel flow are selected using "b" and "c".
Metric or US for "b" is selected by the value of "c" in P00.
The volume can also be displayed in units of weight by
setting "b" and entering the density of the fluid in P32.
The value of "a" determines the temperature units when
the UP key is pressed in the operating mode.
bVolume Weight (set also P32) Open Channel Flow
US Metric US Metric US Metric
0ft
3m3lbs (pounds) – ft3/time m3/time
1gallons liter tons tons gallons/time liter/time
cTime
0Sec
1Min
2Hour
3Day
aTemperature
0°C
1°F
P01: - ba Bar Graph and Measurement Mode
Factory default value for P01 is: 11

51-638 Echotel Model 338 Two-Wire Ultrasonic Transmitter 12
P03: - a Displayed Values
(Rounding & Decimal Position)
Factory default value for P03 is: 0
Level and distance applications do not use P03 since the
biggest number that can be displayed on the 6 digit LCD
is 600 cm, or 240 inches. Displayed values for volume and
open channel flow applications can become quite large,
and for this reason it may be easier to read the LCD if
rounding is used.
Rounding
Fractional inch changes in a large tank will cause rapid
fluctuations in the LCD when measuring volume.
Turbulence in a tank or open channel flow element may
also cause unwanted display fluctuations. Rounding values
(2, 5, 10, 20, 50) represent the numeric steps the calculat-
ed value will change in the last one (or two) digit(s).
Examples:
P03 = 1 steps by 2: 1,000 ⇒1,002 ⇒1,004 ⇒1,006
P03 = 5 steps by 50: 1,000 ⇒1,050 ⇒1,100 ⇒1,150
Displayed VOL or FLOW
As the numeric display becomes larger in volume and open
channel flow applications, the decimal point is automati-
cally shifted over to accommodate the larger numbers in
the 6 digit LCD.
Values over one million will be displayed in exponential
format where the value (e) represents the exponent. Once
over the value of 1x1010 Err4 (overflow) will be displayed.
aDisplayed Value Steps
01= no rounding
12
25
310
420
550
Displayed Value Decimal Position
00.000 – 9.999 x.xxx
10.000 – 99.999 xx.xx
100.000 – 999.999 xxxx.
1000.000 – 9999.999 xxxxx.
100000.000 – 99999.999 xxxxxx.
1 million – 9.99999*109x.xxxx : e
(exponential form)
over 1*1010 (overflow) Err4

13 51-638 Echotel Model 338 Two-Wire Ultrasonic Transmitter
P04: Range
Range is the maximum measuring distance. For level and
volume applications this is the distance from the face of
the transducer to the bottom of the tank.
LEVEL = P04 (programmed) – DISTANCE (as measured
from transducer face to liquid surface)
Since the measurement accuracy of the 338 depends on a
correct value of P04, it is critical to know the exact dis-
tance between the face of the transducer and the bottom of
the tank. If this value is unknown, it can be set using the
"GET LEVEL" command. Make sure the tank is empty,
or at the 0% level mark. While in P04, press the ENTER
key so that the four digit parameter is blinking. Press the
UP + DOWN keys simultaneously for 3 seconds,
and the unit will display the measured distance between
the transducer face and the bottom of the tank. If satisfied
with the displayed value press the ENTER key to accept
this as the range value.
The factory default range value of 20 feet (6 meters) can
be displayed while in P04. Press the ENTER key until
the four digit parameter is blinking, and then simultane-
ously press the NEXT + DOWN keys. The default
value will be shown. Press the ENTER key to accept
this value, or input the appropriate value for the specific
application.
Range values will be displayed as shown.
Engineering Unit Display Format
mx.xxx or xx.xx
cm xxx.x
ft xx.xx or xxx.x
inch xxx.x

51-638 Echotel Model 338 Two-Wire Ultrasonic Transmitter 14
P05: Dead Zone
Factory default value for P05 is: 10.0 inches
Non-contact ultrasonic transmitters require a "dead zone"
or "blind space" between the face of the transducer and
the maximum liquid level. The minimum dead zone for
the Model 338 is 10" (25 cm), as shown in the drawing at
left. The 338 will not process any ultrasonic signals within
the dead zone. For this reason, it may be necessary to
mount the transducer in a standpipe to enable the 338
to measure all the way to the top of a tank. Refer to
Section 1.2.5, Standpipes, for information on mounting in
standpipes.
For most applications the factory default value of 10" (25 cm)
is used, which allows the unit to have the smallest possible
dead zone. Entering a value larger than 10" (25 cm) allows
the unit to block out any false echoes originating from the
bottom rim of a standpipe, or from any object protruding
into the ultrasonic beam close to the transducer. Since the
338 will not measure any value inside the dead zone, the
full tank (usually 20 mA) value will need to be adjusted if
the dead zone value is changed.
P06: Far-end Blocking
Factory default value for P06 is: 00
Level or Volume Applications
Far end blocking is used to ignore false reflections caused
by objects at the bottom of the tank. This can be helpful
with tanks that have heaters, or other objects at the bot-
tom of the tank, and also with conical bottom tanks
where level measurement may not be necessary below a
preset level.
P06 is entered as the distance from the bottom of the tank
to top of the interfering object. If the liquid level falls
below this preset level, and enters the far end blocking
section of the tank:
1. "Sub 0" will be shown in the LCD
2. "FAIL" will blink on/off
3. The mA output will hold the value that corresponds to the
far end blocking level
Range (P04)
Dead Zone (P05)
Far End
Blocking (P06)
DIST=distance (measured)
LEV=level (P04-DIST)
Span
(P04-P05)

15 51-638 Echotel Model 338 Two-Wire Ultrasonic Transmitter
Open Channel Flow Applications
Far end blocking is used in open channel flow applications
to force a zero flow value when the level is below the
chosen value. This allows the totalizer to stop recording
flow when the level drops below the preset value. If the
liquid level in the flume or weir falls below this value the
338 will:
1. Indicate "No Flow" on the LCD module
2. Hold last valid mA current value
NOTE: When the liquid level is above the far end blocking section the
calculation of level, volume, or open channel flow is based on
the programmed tank dimensions; therefore, the measured or
calculated process values are not influenced by the far end
blocking value.
NOTE: P07, P08, and P09 are not currently used with the Model 338
transmitter.
1.6.2 mA Current Output Settings
P10: 4 mA current output value
P11: 20 mA current output value
The mA current output values are calculated according to
the Measurement Mode that was selected in P01. For %
measurements (LEV or VOL) the 4 mA and 20 mA values
are entered in the relevant engineering units of LEV (ft, in,
m, or cm) or VOL (gal, ft3, m3, or liters).
Though P10 and P11 are usually set with 4 mA at the
bottom of the tank and 20 mA at the top, they can be
reversed with 20 mA at the bottom and 4 mA at the top.
P12: -a Fail-safe Indication
Factory default value for P12 is: 0
The Model 338 continuously performs diagnostic checks
on the electronics and transducer, and confirms that the
unit has been configured properly. Refer to Section 1.8,
Diagnostic Error Codes, for a listing of all the errors codes
that can be displayed by the 338 transmitter. P12 is used
to set the desired mA output value if any faults are detect-
ed. The fail-safe mA values shown below are in accordance
with the NAMUR NE 43 standards.
cFault Values
0Hold last value
13.6 mA
222 mA

51-638 Echotel Model 338 Two-Wire Ultrasonic Transmitter 16
NOTE: P13–P19 are not used by the Model 338 transmitter.
1.6.3 Performance Enhancement
Registers 20 through 33 can be used to enhance the per-
formance of the Model 338 in specific applications.
P20: - - - a Damping
Factory default value for P20 is: 5 (60 seconds).
Parameter register 20 can be used to reduce undesired
fluctuations of the display and output, and enhance per-
formance in turbulent applications.
P22: - - - a Dome top tank compensation
Factory default value for P22 is: 0.
Non-contact ultrasonic transmitters can occasionally
receive two or more echoes when the transducer is mount-
ed in the center of a domed top tank. If the transducer can
not be positioned away from the center of the domed top,
the 338 provides compensation to reduce the effects of
multiple echoes.
P23: - - - a Register P23 is not used with the
Model 338
Factory default value for P23 is: 0.
aDamping time Little to no Moderate to heavy
(seconds) turbulence/agitation turbulence/agitation
0no filtering only used for testing purposes
13 acceptable not recommended
26 recommended acceptable
310recommended recommended
430recommended recommended
560recommended recommended
aCompensation Situation
0OFF Use when the Model 338
can be mounted off center
in the domed top tank
1ONUse when the Model 338 is
mounted in the center of a
domed top tank

17 51-638 Echotel Model 338 Two-Wire Ultrasonic Transmitter
P24: - - - a Target tracking speed
Factory default value for P24 is: 0.
P25: - - - a Echo selection within the measurement
window
Factory default value for P25 is: 0.
Advanced digital signal processing within the 338 forms a
measurement "window" around the echo that is reflected
off the surface of the liquid. This measurement window
determines the distance that is used to calculate the level,
volume or open channel flow. A visual of this window is
shown at left as it would be seen on an oscilloscope.
Some applications may have multiple echoes that result
from false targets or noise within the vessel. Register P25
provides two different echo selection modes for the 338 to
use in forming the measurement window around the prop-
er signal.
Received
signal
amplitude Echo 1
Echo 2
"t" ultrasound flight time t
aTracking Speed Application Conditions
0Standard For most applications
1Fast For fast changing level
2Special Used only in special applications. The meas-
uring window (see P25) becomes inactive,
and the 338 responds instantly to any target.
This can be used for extremely fast target
tracking, but is not recommended for level
applications.
Note: The maximum range is reduced in half
when this is used.
aEcho Selected Application
0Echo with the highest This default value is used for
amplitude most Model 338 applications.
1First Echo For applications where false
targets may create multiple echoes