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19. CUSTOM CURVE LINEARIZATION
Curve.exe
is a DOS-based, executable PC
program used to set up an Extended meter
so that the readings have a user-defined,
non-linear relationship with the input signal.
For example, it allows a meter to correct for
non-linearity of transducers, or to display
volume from pressure at the bottom of an
irregularly shaped tank. The linearizing para-
meters are downloaded into non-volatile
memory of the meter. The curve fitting algo-
rithm is uses quadratic segments of varying length and curvature, and provides diagnostics to
estimate curve fitting errors. The program is self-prompting, avoiding the need for a manual.
PREREQUISITES
1)
PC-compatible computer with an available RS232 or USB port.
2)
Extended meter*.
3)
A serial communication board in the meter. This
board can be removed following meter setup.
4)
A suitable cable to connect the meter to a PC.
5)
Curve.exe
software (downloadable at no charge).
GETTING STARTED
Download
curve.exe
into the same directory that will contain your data files, such as
c:\curves
. Set the meter to custom curve linearization. To do so, press the
key to get to
ConFG
, then set the fifth digit to
1
. This digit will only be displayed with an Extended meter*.
Set the meter baud rate to 9600. To do so, press the
key to get to
SEr 1
, then set the
entry to
__
050
. Set the meter address to 1. To do so, press the
key to get to
SEr 2
, then
set the entry to
_
0011
. To execute the program from Windows, simply double-click on
curve.exe
. No software installation is required.
OPERATING MODES
The program will prompt you to enter your data in one of four modes. Pressing
R
(Enter) at
any time returns you to the main menu.
1) Text file entry mode,
with an X value in one column and a Y value in another. There
can be additional columns, which are ignored. The file must have a DOS name of up to
8 characters and the extension .RAW. There can be from 5 to 180 rows. X is the input
value and should be in the unit of measure for which the meter was set up, such as mV,
V, mA or A. Y is the desired corresponding reading and can range from -99999 to
99999 with any decimal point.
2) 2-coordinate keyboard entry mode,
where an actual X input signal is applied, and the
desired Y reading is entered from the keyboard.
3) 2-coordinate file entry mode,
where an actual X input signal is applied, and the
desired Y reading is provided from a file.
Summary of Contents for 800 plus
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