two measurements: one a
Precip Rate
with an interval of one hour, and another as
Precip Rate
with an interval of one day.
Usually, a slope is applied to convert the counts from the tipping bucket into
inches of rain. For example, setting the
Slope
to 0.01 means that one hundred
counts from the tipping bucket equal to one inch of rain.
SDI-12
SDI-12 is a standardized three wire digital interface. Many manufacturers
provide SDI-12 sensors that measure different environmental effects. SDI-12
sensors provide digital data which improves their reliability and accuracy in terms
of logger sensor communications. For more details on SDI-12, please refer to the
More About SDI-12
section and to the
wiring section
. Also see how to read
multiple parameters from the same sensor
.
Setting up an SDI-12 sensor requires the use of these unique setup fields:
SDI-12 Address
Multiple sensors can be connected to the same SDI-12 bus. However, each sensor
needs a unique address. The address is a single ASCII character. Most sensors
default with the address 0. If you are connecting multiple sensors, connect them
one at a time. As each sensor is connected, issue the 0Ax! command, changing
the sensor’s address from 0 to x, where x is a unique number or letter of your
choice. The front panel
Diagnostics->SDI Find
menu can help do this.
SDI-12 Command
When the measurement type is set to “SDI-12”, data is obtained by sending a
command to the SDI-12 sensor. The sensor will reply with the measured data.
The command is set by the user through the “SDI-12 Address” and “SDI-12
Command” fields. For example, if the address is set to “0” and the command is
set to “M!”, “0M!” will be sent to the sensor.
SDI-12 Param
Some sensors will respond with multiple data values. The “SDI-12 Param”
designates which of these data values the user is interested in.
The common setup for SDI-12 sensors is to specify the “SDI-12 Address” as “0”,
“SDI-12 Command” as “M!” and the “SDI-12 Param” as “1”. This commands
SDI-12 device at address 0 to make a measurement and to take the first value
returned. Newer SDI-12 devices support the following additional commands:
MC
Measure and include CRC in reply
C Measure
concurrent
CC Measure
concurrent
and include CRC in reply
R Read
real-time
Some SDI-12 devices can return more than one sensor reading, such as a water
quality probe that returns Dissolved Oxygen, Conductivity, Temperature etc.
Some of these devices will return more than one reading when issued a single
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