Campbell CR800 Series - Voltage Measurements - Details; Voltage Measurement Limitations

Section 8. Operation
345
For a complete treatment of current-loop sensors (4 to 20 mA, for example),
please consult the following publications available at www.campbellsci.com/app-
notes:
• Current Output Transducers Measured with Campbell Scientific
Dataloggers (2MI-B)
• CURS100 100 Ohm Current Shunt Terminal Input Module
8.1.2.7 Voltage Measurements — Details
Related Topics:
• Voltage Measurements — Specifications
• Voltage Measurements — Overview
(p. 65)
• Voltage Measurements — Details
(p. 345)
8.1.2.7.1 Voltage Measurement Limitations
Caution Sustained voltages in excess of ±8.6 V applied to terminals
configured for analog input can temporarily corrupt all analog
measurements.
Warning Sustained voltages in excess of ±16 V applied to terminals
configured for analog input will damage CR800 circuitry.
Voltage Ranges
Related Topics:
• Voltage Measurements — Specifications
• Voltage Measurements — Overview
(p. 65)
• Voltage Measurements — Details
(p. 345)
In general, use the smallest fixed-input range that accommodates the full-scale
output of the sensor. This results in the best measurement accuracy and resolution.
The CR6 has fixed input ranges for voltage measurements and an auto-range to
automatically determine the appropriate input voltage range for a given
measurement. The table Analog Voltage Input Ranges and Options
(p. 346) lists
these input ranges and codes.
An approximate 9% range overhead exists on fixed input voltage ranges. In
other words, over-range on the ±2500 mV input range occurs at approximately
2725 mV and –2725 mV. The CR800 indicates a measurement over-range by
returning a NAN (not a number) for the measurement.
Automatic Range Finding
For signals that do not fluctuate too rapidly, range argument AutoRange allows
the CR800 to automatically choose the voltage range. AutoRange makes two