Download Manual - Laurel Electronics, Inc.

DC ratio operation is available for use with bridge and potentiometer type sensors, and is unaffected by variations in the power supply voltage. This mode is selected at the input connector
and by setting the Signal Input Mode to Ratio.
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 Coordinates 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 Out” tab, set Range to “4-20 mA current”, “Lo Range Reading” to 0.0A, and
“Hi Range Reading” to 200.0A.
- 21 -