Xylem H-4161 - Manual (Page 5)

Chapter 1
Introduction
H-4611
Introduction 1-1
Figure 1 H-4161 SDI-12 to 4-20mA Interface
1.0 Introduction
The W ATER LOG ® H-4161 is a SDI-12 to two-wire 4-20mA interface module. The H-4161 can be
programmed to either monitor communications between a data logger and its attached sensors or to
initiate measurements by itself. The measurement data is scaled as needed and output to a precision two-
wire 4-20mA current transmitter.
The “SDI-12 Serial-Digital Interface” is ideal for data logging applications with the following
requirements:
Battery powered operation with minimal current drain
Low system cost
The H-4161 has the following features:
Precision 16-bit 4-20mA current output
1000V output isolation from the SDI-12 bus
Can monitor the SDI-12 bus for a specified sensor address and data parameter
Can initiate measurements to an attached sensor
Programmable “Max” and “Min” data set points for automatic data scaling
Manual “set” of the 4-20mA output using an extended SDI-12 command
Two SDI-12 ports