2-wire decoder technology allows control of large irrigation systems over long distances. It involves inserting waterproof decoder modules in a low voltage, direct burial 2-wire path. Decoders are electronic devices connected to a wire path from an irrigation controller. A decoder system operates irrigation valve solenoids. It receives both signal and power from the same wire path. It lets the installation of irrigation stations down the same wire run. There is no need for a separate power wire for each solenoid. A 2 wire decoder irrigation system has several benefits.
A decoder system attracts a lot of users. One of the reasons is the ability to operate 99 stations using two wires only instead of more than a hundred wires. These systems save connectors and labor in connection with many individual wire runs.
The electrical efficiency of a decoder system is undeniable. It has the ability to operate many solenoids over long distances. Longer runs are possible with heavier wires but they are not practical.
A decoder system has resistance against lightning. No irrigation system is immune to lightning, even 2-wire decoder irrigation systems. A decoder system has less wire in the ground. It has an excellent grounding and surge-suppression when installed well. Most regions with high lightning exposure use these systems.
Most irrigation systems experience problems over time. These are due to degradation or faults in the field wiring. New techniques and devices simplify fault-finding today. There are brands offering handheld devices to aid programming and diagnostics of decoders. There are only two wires per path in a decoder system. There is only a single output module for the decoder functions. It has diagnostic LEDs for easier troubleshooting. The controller operating system is like a conventional ACC. Those familiar with ACC operations will find it easy to master decoder programming.
Installers can position decoders anywhere along the 2-wire path. The installer can assign station numbers. These make it easy to accommodate changes to the original landscape plan. The number assignment of decoders does not need to be in physical order. Station 3 can be between station 1 and station 2.
It is easy to expand irrigation systems after the original installation. No need to run spare wires or retrofit new wiring back to the controller. The installer only needs to find the closest point in an existing 2-wire path. He or she then splices in a new decoder station when there is a need for extra valve control.
A decoder system has several differences from conventional wiring. One of these is it allows control of many valves over very long distances. It is crucial for an installer to invest in the decoder electronics. The expense for these will be offset by the wire savings.