Xylem H-4161 - Manual (Page 7)

H-4611
Introduction 1-3
Figure 2 The H-4161 monitors the SDI-12 bus for a selected
parameter
1.4 Monitor SDI-12 Communications (Module Mode = 0)
During normal operation the data recorder sends commands to one or more SDI-12 sensors and
subsequently collects data from the sensors. As a “data monitor”, the H-4161 passively monitors the
communication between the data recorder and its SDI-12 sensors. The H-4161 waits for, and collects a
specified data parameter from a specified sensor. The data is scaled and used to update the H-4161's 4-
20mA output. In this mode the H-4161 monitors, but does not transmit data to the SDI-12 bus. The data
recorder must initiate any sensor measurements.
The data recorder can also communicate with the H-4161 directly as a normal SDI-12 “sensor”. Using
extended SDI-12 commands, the data recorder/user can manually set the 4-20mA output, observe the last
data collected or configure the H-4161.