LAUREL LTE Series, Руководство пользователя

Страница: 21 / 48

- 21 -
For use with potentiometers, where excitation and signal share the same ground, select 5V
(not 10V) excitation, set Mode to Ratio, and set Range to 0.2V. Again, the meter will use the
excitation voltage as the reference for A-to-D conversion. Often used for length measurement.
Example: Transmit the digital reading in amps and as 4-20 mA from a 500-100 current shunt
Application: Use a 500-100 (500A, 100 mV) current shunt. Digitally transmit the DC current
reading in amps with 0.1A resolution. Also transmit a 4-20 mA signal corresponding to 0-200A.
Solution:
• Jumper signal conditioner for ±200.00 mV range.
•
Under “Input+Display” tab, set “Option Board” to DC, Mode to DC V, Range to 0.2V,
“Decimal Point” to dddd.d, and “50/60 Hz Line Freq” to 60 Hz to reject 60 Hz noise.
• Under Scaling tab, if Coordinate s is selected, set “High In” to 0.1V and “High Read” to
500.0A. For this application, Coordinates is the easiest, most intuitive scaling method.
• Under Scaling tab, if “Scale, Offset” method is selected, set Scale to 0.5. The reason is that
a 200 mV full-scale input corresponds to 20,000 input counts, where each input count is
10 µV (as for the 200 mV scale of a 4-digit meter). These 20,000 input counts need to
correspond to 10,000 output counts, where each output count is 0.1A.
• Under “ Analog Ou t” tab, set Range to “4 - 20 mA current”, “Lo Range Reading” to 0.0A, and
“Hi Range Reading” to 200.0A.