Vaisala Hydromet Data Collection Platform - Manual (Page 345)

Chapter 7 ____________________________________________________________ Technical Data
VAISALA______________________________________________________________________ 343
The dual RS-485 module also provides an SDI-12 connection. The SDI-
12 line uses one wire for data and is limited to a maximum length of 60
meters.
Figure 178 on page 343 provides a schematic wiring diagram
for the SDI-12 connection and the 12 VDC power supply for a sensor.
The jumper settings should be as shown in
Figure 176 on page 342 .
Simultaneously with the SDI-12, you can connect channels A and B in
the 2-wire RS-485 mode. If you take all three channels in use, you either
need three free connectors in the flange or an optional junction box.
1006-103 Figure 178 Dual RS-485 Wiring Diagram for SDI-12 and
12 VDC Power Supply