Project Description

2/2 Way , DIAS Solenoid Coil (2 Wire System)

(DIAS: Decoder in a solenoid)

Model: S391-DIAS-2W

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Model :S391-DIAS-2W

Special Features

  • Combines a 2Wire Decoder and Solenoid Coil into one product.
  • Reduces number of field wire connections by 50%
  • Multi-colored LED provides feedback — reduces troubleshooting time.
  • Screws into most valves. (Threaded adapters for Hunter & Rain Bird).
  • Compatible with all Underhill & Tonick 2Wire Controllers and Converters.
  • Superior distance and number of concurrent active stations.
  • No grounding necessary along the 2Wire path.
  • Built-in powerful protection from Lightning surges.
  • Can re-use old wiring. Earth leakage on 2Wire well tolerated.
  • ‘Out of the box’, works as a normal 24VAC solenoid with ultra low current.
  • Works with the Tonick Sensor decoder range; soil moisture, flow and pressure.

DIAS Electrical Specifications

  • 18-32 VAC, 60 Hz preferred. (Low cost inverters available for 50Hz regions)
  • In normal 24VAC solenoid mode, works equally with 50Hz and 60Hz.
  • In-Rush Current – 250mA
  • Holding Current – 25mA (2-way solenoid), – 55mA (3-way solenoid), relatively independent of applied AC voltage.
  • Idle Current — 5.4mA
  • Maximum Active Valves:  2 way:16
  • Maximum operating distance:
    1) 2.5mm2 conductors– 5000m– 16,000 feet
    2) AWG14 conductors– 4000m– 13,000 feet
    3) AWG10 conductors– 10,000m– 32,500 feet
  • Solenoid thread size:
    1) ¾” UNF20, front thread
    2) 1/8” BSP Female, 3-way back thread

Advanced Features

  • The DIAS can be programmed from a low cost Portable Programmer.
  • Program the corresponding station number into DIAS as part of initial controller setup and installation. Addresses 1-127.
  • Connects to a 2Wire path with a single pair of wires directly to the solenoid.
  • Ultra-low holding current allows more stations to be operated at one time.
  • Program decoder’s address to 0 to turn into a normal 24VAC solenoid.
  • The DIAS comes standard with co-molded LED providing visual feedback:
    1) Green Colour — Decoder is “Ready” as a decoder
    2) Orange Colour- Solenoid is “ON” as a decoder
    3) Red Colour —Solenoid is “ON” as a normal 24VAC solenoid
    4) No Colour— No Power, broken wire.
  • 3-Way Solenoid (In decoder mode, standby. Green)     2-Way Solenoid (In conventional solenoid mode, on. Red)

                                   3 way solenoid                                                                 2 way solenoid


  • It is not possible to mix conventional Tonick TW/2W or Underhill TK-DEC-1 decoders with DIAS-C; it must be all one or the other.
  • DIAS-C is best run at 60Hz to achieve full performance.
  • A useful range of low cost inverters will be made available for 50Hz areas. One of these would replace the transformer that normally accompanies the controller. Versions of inverters include 12VDC input, 24VDC input and Universal line power input 90-265VAC.
  • Use of an inverter will remove the occasional instance of poor controller performance on site, due to noisy and distorted incoming 115V/230V line power.
  • It will not be possible to combine a DIAS electronic circuit with a 3rd party solenoid.
  • De-rating the BT2 at ambient temperatures greater then +50degC will be less likely required, as currents with typically 8 DIAS-C on together are well within its 70degC range
  • When working as a normal 24VAC solenoid (address 0), the DIAS-C cannot be used with many 3rd party irrigation decoders. In this mode the DIAS-C is designed to work with multi-wire systems that feed 24VAC to irrigation solenoids.