Xylem H-4280 - Manual (Page 9)

Chapter 2
Installation And Setup
H-4280
Installation And Maintenance 2-1
2.1 Installing The H-4280
The W ATER LOG ® H-4280 is an 8-channel analog to digital SDI-12 “sensor”. Many sensors such as
potentiometers, thermistors, and pressure sensors can be connected directly to the H-4280
2.2 General Installation Recommendations
The H-4280 housing and connectors are not weather tight. The H-4280 must be installed in a protected
location or a weather tight enclosure. The housing has a 4-terminal connector for making power and SDI-
12 connections and a 2-segment, 12-terminal connector for connecting the analog inputs. The connectors
can be detached while making the connections.
Caution: Remove all power from the unit before making any connections.
Before beginning the installation take a minute to plan out your station grounding and wiring scheme. Use
a single point ground system design to avoid having high current (power) flowing into or out of the ground
terminals of the analog input connector. If your sensors have separate signal and power connections,
connect only the signal and its ground reference to the input connector. Use shielded cables where possible.
Use a shielded, twisted-pair cable when making connections to a differential input. Install lightening and
other transient voltage protection if the sensors and wiring are exposed to damage. Power the sensors from
the same battery or power supply which supplies the data logger, this makes certain input voltages to the
H-4280 are not present if the H-4280 is powered off.