Applications, Process, Strain & Potentiometer Follower Meter

In potentiometric (or potentiometer follower) applications, the signal from a sliding contact voltage divider can be converted to engineering units such as position, level or percentage. By operating in a ratiometric mode, the meter will remove any effects caused by variations in the excitation supply.

For use with a 1 kohm potentiometer, the recommended applied excitation voltage is 10 V, and a 2 kohm resistor should be placed in series with the excitation output and excitation return leads. This will allow the meter's 2.0000 V scale with a high input impedance of 1 Gohm to be used.

Powering two-wire transmitters		Testing with peak detection
The isolated 24 Vdc, 50 mA excitation output, which is standard with all Laureate meters, is ideal for powering two-wire, 4-20 mA transmitters. The same two wires are used to apply voltage and carry the output current. Inside the meter, the 4-20 mA current is dropped across a 10 ohm resistor and sets up a 40-200 mV voltage, which is then sensed by the meter and scaled to engineering units.		Destructive testing is an ideal application for the Laureate strain meter. Peak readings are automatically captured at rates up to 60 per second, while the display updates at a legible 3.5 readings per second. The peak reading can be recalled at the push of a button or be transmitted via RS-232 or RS-485. The meter provides isolated 10 Vdc power for up to four (4) the strain gauges and can be scaled to read out directly in engineering units from -99,999 to +99,999.
Custom curve linearization		Rate from successive readings
The Laureate DC meter with the Extended main board option allows exceptionally accurate custom curve linearization. For setup, up to 180 data points can be entered into a spreadsheet. The system then creates multiple non-linear spline-fit segments, which provide much better accuracy than linear segments. Illustrated, is the readout of volume of irregularly shaped tanks based on measured liquid level or pressure. Altimeters and thermistors are further applications.		The Extended computer board allows the display of rate based on successive readings, for instance flow rate based on changes in liquid level or static pressure in a tank. In the above illustration, the meter displays the rate in gallons at which a horizontal tank is being emptied. The input to the meter can be nonlinear, since only the linearized readings are compared for the determination of rate.