Liquid Controls
Sponsler, Inc.
IT400 Remote Totalizer & Rate Indicator
Page: 7
DOC#:
MN-IT400-R2c.doc
IT400 Operational Overview
The
IT400
flowmeter system will perform the necessary calculations to provide the user with an
optional temperature compensated and optional linearized output of the following values:
•
Rate
•
Total
•
Grand total
•
Errors/warnings
•
Various outputs
Calibration
Calibration of the
IT400
is accomplished using either a linear K-Factor (pulses per gallon) or a
linearized K-Factor linearization table (when the linearizer is enabled). Independent unit conversion
factors and decimal points are available for the rate and total displays. Calibration and configuration
data are stored in an onboard EEPROM for permanent storage. Calibration of the IT400’s reference
circuitry is factory set and is not user accessible. Calibration of the IT400’s reference circuitry should
be performed by factory trained service personnel.
Temperature Compensation
The temperature compensator utilizes a platinum RTD to detect the process temperature. Process
temperature is used in conjunction with the reference temperature and Coefficient of Thermal
Expansion of the measured liquid (menu items) to adjust the rate and total values. When the
temperature compensation is enabled, the temperature warning annunciator (thermometer on the
LCD) will indicate when the process temperature is out of a programmable range. Optionally, an
alarm output as well as a totalizer inhibit function can also be tied to this temperature warning.
Various Coefficient of Thermal Expansions and their reference temperatures can be found in the
appendix. The temperature circuit and associated algorithm, when enabled, increase the
IT400
current consumption from the power source and diminish battery life if running solely from the battery.
A programmable delay function has been provided in order to minimize the impact of the temperature
sampling on the battery life. The delay feature specifies the number of seconds between temperature
value samples. The higher the delay, the longer the battery will last.
Linearization
The linearizer utilizes a linear interpolation algorithm to calculate the rate and total based on a set of
calibration data points programmed by the user. The linearizer has21 points, the first point (lowest) is
automatically set at zero hertz, the remaining 2 to 20 are user programmable. The linearizer table
must have at least two data points in addition to the first (fixed) point and must be ascending in
frequency from the first point to the last. To have fewer than 20 points in the linearizer table, after the
last desired linearization point add one additional point and set the frequency at zero. Zero is an
invalid frequency; this will indicate the end of the table. The
IT400
will not allow frequencies to be
entered out numerical order. Frequencies between zero and the first programmed point will use the
K-Factor of the first programmed point.
