Custom Curve Linearization is a feature available with the Extended version of all Laureate digital panel meters and counters, excluding only temperature meters. It can provide exceptional accuracy from low-cost transducers, extend the working range of transducers, and solve special application problems where there is a non-linear relationship between the input and the desired reading.

Linearizing is implemented in the form of 20 nonlinear spline-fit segments, which provide much better accuracy than a larger number of straight line segments. The typical error will be from 0.1% to 0.01% of full scale, depending on the number of data points used for setup, the error in the data points, and the severity of non-linearities or discontinuities.

Application Examples:

* Non-linear transducers, such as thermistors or CdS cells.
* Fine-calibration of nominally linear transducers, since these will have nonlinear components.
* Extending the working range of transducers at the low and high ends.
* Compensating for inaccuracy of low-cost transducers.
* Altimeters, since the relationship between pressure and altitude is non-linear.
* Rate of ascent based on successive altimeter readings.
* Square root extraction from differential pressure transducers when the signal has a zero offset.
* Volume of irregularly-shaped tanks, such as horizontal cylinders, based on the measured liquid level or pressure at the base of the tank.

Setup is easily accomplished using an external PC, an RS232 cable, and linearizing software furnished by Laurel. To download at no charge, go to the Software Downloads page of www.laurels.com. A Laureate serial communications board is also required in the meter, but can be removed following setup. Three meter programming methods are offered:

1. Spreadsheet Method: From 2 to 240 data points consisting of the input signal in Volts or Amps and the desired reading are entered into an Excel spreadsheet or into a text file. Laurel's software then calculates 20 spline-fit segments and downloads their coefficients into the meter.

2. Actual Input Method: From 2 to 240 input / reading combinations are collected with the meter hooked up to the actual signal source. Laurel's software then calculates 20 spline-fit segments and downloads their coefficients into the meter. This method automatically compensates for any errors in the transducer and meter.

3. Polynomial Method: The mathematical formula relating the input to the output is entered into the computer, which then calculate the spline-fit segments. This method is ideal if the mathematical relationship is known, for example to calculate the contents of a tank based on the known geometry of the tank.

For more information, go to www.laurels.com/linearizing.htm