ESP-LXD 2-Wire Decoder Control System Installation & Troubleshooting Guide
5
2-Wire Path Layout and Connections
The design of a Rain Bird ESP-LXD 2-Wire Decoder Controller system requires careful consideration
to the layout of the decoders on the 2-Wire path. Since a decoder system powers the electric
solenoids through the 2-wire path, the 2-wire path must be able to provide enough voltage to
power the solenoids. There are design specifications limiting the length of the 2-wire Critical Path.
Refer to page eight of this guide for design specifications.
2-Wire Configurations
There are two types of configurations that can be used for the layout of 2-wire paths: STAR or
LOOP. The controller will supply up to four separate 2-wire paths for a STAR configuration and up
to two separate 2-wire paths for LOOP configurations. Depending upon the design of the site,
it is preferable to separate the 2-wire paths into multiple wire runs rather than install a single
2-wire path throughout the site. These wire paths can be configured in either the STAR or LOOP
layout or a combination of the two types. For ease of troubleshooting, the STAR configuration is
recommended.
Star Configuration
For normal installations with 2-wire path runs that are not excessively long, the recommended
layout for the 2-wire path is the STAR configuration. This is to facilitate ease of troubleshooting
the system should it experience a wire fault or short. The distance of the farthest decoder from
controller measured along the 2-wire path is considered the Critical Path of the 2-wire cable for a
STAR configuration. The maximum distance for the Critical Path is 1.65 miles for 14 AWG Maxi Cable,
and 2.63 miles for 12 AWG Maxi Cable. For metric cable the maximum distance for the Critical Path
is 3.0 Kilometers for 2.5 mm² cable.
2-Wire Path Star Pattern Design
