Sutron Corporation X-Link Operations & Maintenance Manual, Rev 1.63 5/24/2016 pg. 167
pressure
redox (ORP)
tank level
temperature
tide and sea state
turbidity
water velocity
weight of snow and ice on a snow pillow
wind speed and direction
Sutron also offers general purpose interfaces for making analog and digital
measurements via SDI-12.
For more information on SDI-12, go to
www.sdi-12.org
.
17.2.
Wiring Guidelines
SDI enables you to connect up to 10 sensors with as many as many as 9
parameters each. The interface is implemented using three wires: data, ground,
and +12V. The ground conductor of the SDI interface line should be large enough
to keep the voltage drop between the data recorder and the sensor to less than
0.5 volts during the maximum sensor current drain. Failure to observe this
specification will cause bad communications and/or bad data. The maximum
current used on the +12V line should not exceed 2 amps at any time.
Please note that Modbus RS-485 and SDI-12 are mutually exclusive. If Modbus
RS-485 is enabled, X-Link will NOT be able to collect data from SDI-12 sensors.
17.3.
Connector
The connector type is not part of the SDI specification. On X-Link, the
connections are made on the terminal block: #14 (SDI-12 Data), #13 (SDI-12
PWR), and #12 (GND). Multiple sensors can be connected to these connections.
17.4.
Setup of SDI sensors
Each SDI-12 sensor has an address from 0 to 9. This address differentiates one
sensor from another. Most sensors are factory default set to address zero (0).
If/when interfacing more than one sensor to X-Link, each sensor must be
assigned a unique address. This is normally done by setting dipswitches on the
sensor or by software commands. Failure to set unique addresses for each
sensor will result in failure of the communications interface (i.e. no data logged).
Consult the sensor manufacturer’s data for information on your particular
sensor(s).
