Power; Reading - Decagon Devices VP-3 Operating Manual

VP-3 User's Manual
5. Communication

Power

The VP-3 is an extremely low power sensor. When continuously
powered, but not making a measurement or communicating, it
uses 30A. When using the sensor as part of an SDI-12 bus, it is
recommended that the sensors be excited continuously to avoid
issues with initial sensor startup interfering with the SDI-12
communications.

Reading

When reading the VP-3 in SDI-12 mode, the first number output
by the sensor is vapor pressure in kPa, the second number is
temperature in Celsius, and the third number relative humidity in
a unitless ratio from 0 to 1 (0 – 100%).
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