Technical Note — Nelson TWIG Wireless Control System

Rowan Chase

Created: ; updated: .


The Nelson TWIG Wireless Control System allows control of low powered DC latching solenoid valves for automated irrigation.  Adding a C3 extends this to the cloud for remote monitoring and control.

The Nelson TWIG Wireless Control System consist of four products :

Nelson TD200 Controller

The TD200 is the 'Master' of the wireless network and will connect directly to a C3.  The TD200 is capable of controlling up to 200 valve itself, however the C3 will be able to provide remote control via Jain Logic or Observant Global for just 30 valves at a time.


The TWIG is a network node device that will be placed at the solenoid valve site.  It provides control of low voltage latching solenoids in configurations of either one, two or four valves.  Two D-Cell batteries will last it an irrigation season.

TWIG Repeater

The TWIG Repeater can be used to increase range of the wireless network or bounce the signal over or around obstacles such as dense vegetation or hills.

TWIG Contact

The TWIG Contact is a network node device that will be placed at a pump site.  It provides 4 electrical contacts allowing the control of up to 4 devices such as a pump, generator or engine.

Jain Logic and Observant Global

As part of Jain's monitoring and control platforms, the Nelson TWIG Wireless Control System with C3 will allow growers to remotely manage up to 30 control points.  Features include:

  • Grower can independently schedule assets using the Schedule App.  Eg. set valve 1 to open at 9am for 1 hour, then open valve 2 for 2 hours, then valve 3 for 3 hours, etc..
  • Activation of solenoids/contacts is logged and can be displayed in Monitor/Analyze Apps.
  • Manual control of each valve/contact.
  • SMS alerts for schedule or system failures.

Required Hardware

Minimum hardware requirements are:

  • 1 x Jain/Observant C3
  • 1 x Nelson TD200 
  • 1 x Nelson INTERFACE KIT, RS-485 TO RS-232 – TD200 (part no. 12988)
  • 1 x TWIG or TWIG Contact


For details on installing the Nelson TWIG Wireless Control System, see Nelson's online content.

For connection with a C3 Field Unit the following steps should be taken (the attached PDF document provides further info and images):

  1. Take the Nelson Interface Kit Card and plug it into the bottom of the TD200.  All pins should be plugged into the CCA port.
  2. Take the smaller supplied cable and plug one end into the card's port labelled "RS232".  The other end should plug into the TD200's C port, the middle connector.
  3. Plug the longer cable into the port labelled "RS485"
  4. Remove the rubber plug at the bottom of the TD200 enclosure and replace it with the provided strain relief.  Tighten the strain relief so it is snug on the cable.  If the box does not have a hole, drill a 7/8" diameter hole directly above the existing hole for the power cord.
  5. Strip 1/4" off the leads on the other end of the longer cable and insert the cables into the C3 as in the table below.  Tighten the screws to hold the wires in place.

    Wire Colour C3 RS485 Terminal
    Black Ground
    Red B
    Brown A
  6. At the TD200, turn the left dial to "Setup".  Scroll down to control source and press enter.
  7. With the * on the first line, press enter.  Scroll up or down until "REMOTE" appears by the *. Press enter, then exit the menu.
  8. Turn the left dial back to "View" and the right dial to "Off".  The TD200 is now controlled by the C3.


Nelson TWIG Wireless Control System Product Page

Nelson TWIG System how-to videos

Schedule App Videos

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