25
51-638 Echotel Model 338 Two-Wire Ultrasonic Transmitter
1.6.6 Linearization Table
P47
Linearization
Factory default value for P47 is: 0
The Model 338 offers a 32-point linearization table for
primary flow elements (open channel flow) or tank shapes
(volume) that are not in the standard software. This table
can also be used for establishing a level to level relation-
ship, if the speed of sound (see P31) is not known for a
vapor. To enable the linearization feature, change the value
of P47 from 0 to 1.
P48
Linearization table
Factory default value for P48 is: 0
The linearization table is developed by pairing level values,
with known volume or open channel flow values.
Data is entered into the table in a 2
×
32 matrix, consisting
of two columns:
The left column (indicated as "
L
" in the display) contains
the level values measured by the Model 338 unit. The
right column (indicated as "
r
" in the display) contains the
volume, open channel flow, or level value corresponding to
that height in the vessel or primary flow element. The fig-
ure below shows how to enter data into P48.
P47
Linearization
0
Off (factory default)
1
On
Left column "L"
Right column "r"
Level measured by the 338
Volume, Flow or Level to be
transmitted and displayed
Number of
programmed data
pairs in the table
Address
(Serial number)
of the data pair
Left
Column
Right
Column
to be transmitted
and displayed
LEVEL
Measurement
value
ENTER
ENTER
ENTER
ENTER
(Enter table)
UP + DOWN
ENTER + DOWN
(Exit table)
UP, DOWN, NEXT
(Enter values)
UP + DOWN
(Copy present measurement)
ENTER + UP
Copy value of previous address
NEXT + DOWN
(Load a "0" to close table)
NEXT + UP
(Cancel modification of this data)
LEVEL
VOLUME
FLOW
48:_ _xx
yy xxxx
yy xxxx
L xxxx
r xxxx
...
...
...
...
