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  • Long Range Wireless Solid State Relay Board
  • Available with 1, 2, 4, or 8 On-Board Relays
  • Available with Your Choice of Solid State Relays
  • ProXR Command Set Used by Industry for Many Years
  • Supports Windows, Mac, Linux, and Android
  • Supports LabVIEW and Visual Studio
  • Virtual COM Port Communications
  • Use NCD Base Station Software to Learn Commands


SKU: PL_S3B_SS UPC: 689860072374 Categories: , ,


NCD Long Range Wireless Relay Controller Boards

NCD Long Range Wireless Relay Controller boards make it easy for computers of all types to control relays and monitor analog inputs wirelessly. NCD Relay boards allow you turn relays on or off, flash relays continuously, control relays for a duration of time, and control relays in groups using a cross-platform compatible long range wireless interface. This wireless relay is a ProXR Lite series controller which is a widely adopted standard used by industry for many years.  Equipped with your choice of 1, 2, 4, or 8 on-board relays, the ProXR Lite series wireless Relay controllers suit the needs of most of our customers.  Integrated Analog to Digital Converters may be used to manually control the relays, or they may be used to read external sensors.  Equipped with 8 or 10-Bit resolution, the ADC built into NCD long range wireless relay controller boards add tremendous flexibility for various application requirements.

Long Range Wireless Communications

NCD Long Range Wireless Relay Controllers use the 900HP-S3B communications module.  A USB modem is plugged into a computer and the relay controller is installed in a remote location, up to 2 miles away.  Your computer can be used to talk to the remote relay controller using our Free Base Station Software.  Base Station is designed to help you learn how to use our remote relay controllers.  Using optional high-gain antennas (not included) distances of 28 miles may be achieved in line of sight applications.  Indoor, urban, and non-line of site installations may not be able to achieve the rated range, as all ratings are determined in line of site applications only.  Customer testing is encouraged.  Since mesh networking is supported by the 900HP-S3B communications module, it is possible to “repeat” the wireless signal up to 8 times to extend the useful range.

Getting Started with NCD Wireless Relay Controllers

Start by downloading Base Station at  Plug in one of our 900HP-S3B lone range wireless relay controller and connect a long range wireless Modem to your computer. Run Base Station to access the remote device.  Base Station is a tool designed to teach you all the features built into your controller and provide you with example commands. A single Relay or multiple Relay controllers may be accessed through a single 900HP-S3B Modem which will mount as a virtual COM port on your PC via a USB connection.  Base Station was written for Windows using Visual Studio (source code available from the download link) and shows you all the commands you need for controlling relays and monitoring external sensors.

New Version Now Shipping

Beginning Late 2020, we’ve made some updates to this product to make it better with increased component count while maintaining the same functionality and footprint.  The New Rev G2 Series adds a better power supply circuit to improve noise immunity while providing increased power to the communications socket.  We also improved the relay drive circuit to better handle inductive loads.  We also changed the color of the circuit board to Black and updated the branding to with updated logos.  

This is the same product you have been buying for years, but now with improved electronics and while maintaining the same footprint as the original design.  Most importantly, this is now a Legacy product, which means it will never go obsolete as long as critical parts are still available to us.  Built with our new high-speed pick and place assembly line, we can complete the surface mount assembly process at a rate of several thousand units per day with the potential to scale to any volume you could imagine, so you never need to worry about supply quantities or supply chain problems.

Please note that it was necessary for us to remove the integrated temperature sensor in select versions of this product.  This sensor was providing incorrect readings if the relays were active for extended periods of time.  We can help you with an off-board sensor if needed.

Updated Features

  • Updated Logos and Branding, Changed PCB Color to Black
  • Improved Relay Drive Circuit for Greater Noise Immunity
  • Improved Power Supply Circuit using a Switcher Regulator for Lower Heat and Higher Power
  • Adds Compatibility with NCDD5500 Ethernet and our WiFi/Bluetooth Communication Modules
  • Use MQTT to Talk to this Device from the Internet when using our New WiFi Module
  • Use Integrated Web Page to Control This Device when using our New Ethernet or WiFi Module
  • Added Zip Tie Holes Near the Communications Module for a More Secure Installation
  • New Option for Pluggable Connectors on the Analog Inputs
  • Ferrite Beads Added to Better Separate Logic and Drive Circuits from Noise
  • Migrated to Commonly Available LEDs to Address Supply Chain Limitations
  • 100% Identical Firmware with No Changes for Drop In Replacement Compatibility
  • 99% Identical Shape – Only Slight Changes to Connector Positioning for Better Fit and Finish
  • Now Built by our High-Speed Pick and Place Machine for High-Volume Applications
  • Legacy Status Product – Will Not Become Obsolete
  • Removed Faulty Temperature Sensor from Select Versions due to Errant Readings

Base Station Software

Base Station Software was designed to help you learn the ProXR command set.  Explore ProXR features using our Graphical User Interface.  Watch data bytes flow to and from the board, so you easily understand the command execution process.  There is no faster or easier way to learn how to automate than Base Station, as it was designed to work  with our complete array of communication modules, including Wireless, Ethernet, USB, RS-232, and many more.  You only need a Windows 8 or 10 Computer to Run Base Station.  Base Station was written in Visual Studio, and we even provide the source code to help you on your way! Learn More about Base Station Software Here.

Base Station Software Controlling NCD Relay Controllers
Base Station Software Controlling NCD Relay Controllers

AD8 8-Channel 8/10-Bit Analog to Digital Converters

ProXR Analog to Digital Inputs are used to Read External Sensors or Manually Control On-Board Relays

This controller is equipped with 8-Channels of 8/10-Bit Analog to Digital Converters, capable of reading analog voltages from 0 to 5 Volts DC.  The ADCs on this controller allow monitoring of external sensors or contact closure input detection.  Connect external temperature sensors, light sensors, current sensors, buttons, switches, or anything else that generates a 0-5VDC analog or contact closure output.  With 8-bit resolution, analog inputs will convert 0-5 Volt signals into a value from 0 to 255.  With 10-bit resolution, values of 0 to 1023 may be measured.  Input resolution is software selected.  Simply ask the controller for the analog value of each input, and the controller instantly responds.

Relay Activator and Analog Inputs

The Relay Activator control panel allows analog inputs to directly control relays.  Simply connect the analog inputs to buttons or switches and trigger basic relay on or off functions to take manual control of the on-board relays.  The Relay Activator control panel allows you to define 8 functions for each of the 8 inputs.  Functions include turning relays on or off, toggling the state of relays, momentarily flash a relay, momentarily toggle the flashing function of a relay, turn all relays on, turn all relays off, and push notification events.  When push notification events are configured, the controller generates a packet of data every time the inputs change state.

Use the Relay Activator to Configure Analog Inputs for Direct Control of Relays
Use the Relay Activator to Configure Analog Inputs for Direct Control of Relays

Learn More about ProXR Series Controllers

Base Station helps you learn how to use ProXR Series relay controllers.  In this video, we will cover some of the most commonly used features.

Download Base Station

Download the Latest Version of Base Station and Source Code for Visual Studio.

ProXR Quick Start Guide

Online Manual for ProXR and ProXR Lite Series Controllers

Good to Know!

NCD ProXR Series Controllers have been in production for many years and have amassed a large user base since their initial release in the early 2000s. Due to the large client base, we have no plans to discontinue this line of products. In many cases, we are upgrading these devices to make them compatible with automated assembly processes along with improved driver and power electronics capable of supporting many communication technology changes well into the future. Rest assured, ProXR will continue to be a stable part of our product line for many years to come. ProXR series controllers manufactured with a Black circuit board have been migrated to automated assembly and are considered to be the final iteration of this product. These devices can be manufactured in high volumes in a much shorter period of time.

LabVIEW Relay Control

LabVIEW ProXR Relay Drivers
ProXR Analog to Digital Inputs are used to Read External Sensors or Manually Control On-Board Relays

NCD supports integration of NCD relay controllers using LabVIEW.  We have included samples and drivers for basic and advanced operation which cover most functions including Relay Timers.  We have posted several tutorials on this topic here.

ProXR Lite Communication Options

We take communications seriously, as we believe in modular communications and firmware that properly supports scalability into future interface technologies.  ProXR controllers support API communications, which effectively wrap every command with a header, payload, and checksum to ensure reliability.  NCD API commands increase processing speed because no serial timeout is required prior to command processing.  NCD API commands increase reliability, as only a proper checksum will authenticate a command and allow it to process.  When we first implemented API, internet communications via a TCP/IP socket could be realized because the timing problems of internet communications were eliminated.  While API is optional, it is strongly advised.  Our Base Station software uses API communications, so it’s possible to control a ProXR controller over the internet after configuring port forwarding on your router.

ProXR series controllers are the world’s most adaptable controllers, capable of communicating with a wide variety of communication options.  Pick any of your favorite communication technologies: Bluetooth, USB, WiFi, Ethernet, Key Fob, RS-485 or RS-232. ProXR easily adapts to the communication technologies you need most.  We are committed to modular communications, so your ProXR series controllers can easily be retrofitted for other applications as your needs change.  ProXR controllers are never obsolete, as we are actively releasing new communication technologies that greatly enhance the connectivity of our ProXR series controllers.

Communications Module Included

802.15.4 Module Wireless

Long Range Wireless Industrial Mesh

Long-Range Wireless Mesh networking is our favorite of all wireless communication technologies.  This is the ONLY communications technology NCD recommends on the factory floor, operating at a safe 900MHz.  Mesh technology will hop data from one location to another to reach its intended destination, users do not need to do anything other than make sure wireless modules stay within hopping range of each other.  We use the Digi 900HP-S3B module in many of our products, as this is the best industry has to offer.  With a 2 mile range between modules and up to 8 hops, it is possible to cover 16 miles of wireless territory using this technology.  Using high-gain antennas, this module is capable of communicating to a remote module up to 28 miles away.  Please note that data hopping only works between live devices.  Data will not hop between sleeping sensors.  Data will hop from sensors to gateways and modems.  Data will also hop between gateways and modems.  Learn more about our long range wireless module here.

Relay Options

Solid State Relays Option

Solid state relays are ideal for agricultural switching applications, or remotely located switching.  SSRs are frequently chosen to control pumps, valves, solenoids, lights, and other high-reliability applications.  NCD solid-state relay controllers do not include solid-state relays, but you will have the option to choose the type of solid state relays you require when customizing your product. This controller is designed specifically to fit select Crydom solid-state relays, but may be compatible other solid-state relays made by other companies. Review Solid-State Relay Options


AD8 Analog Input Usage Notice

Analog Inputs should not have a voltage present when powered down.  Use a 220 Ohm current limiting resistor on each input to prevent damage to the controller if voltage will be present on the analog input when this controller is powered down.  Do not exceed 0 to 5VDC on any analog input or the on-board CPU will be damaged.  Most analog inputs include a 10K Pull Up/Down resistor to help keep the inputs quiet when not in use.  This 10K resistor may slightly bias the readings of some sensors.

900HP-S3B Wireless Compatibility Notes

Notice: Compatibility Notes Does NOT Apply to the Following Products:

  • NCD Enterprise Solutions
  • NCD Wireless Sensors
  • NCD Enterprise Modems and Gateways

Notice: Compatibility Notes Applies to NCD Industrial Products, Including Fusion, ProXR, ProXR Lite, Taralist, and Reactor Series Products.

Compatibility Notes

When using an 900HP-S3B communication module, it is essential that you use the ZIGMO_PCB to configure the module settings.  Long-Range wireless sensors may be programmed over the air without removing the communications module.

A 900HP-S3B Modem or a gateway of some kind that support the 900HP-S3B communications module will also be required.

Choosing a Solid State Relay

Please examine the datasheet of each solid state relay carefully, as SSRs do not function exactly like mechanical switches.  SSRs frequently have minimum load requirements, and some require external snubber circuitry for certain applications.  SSRs do not typically work with volt meters in the same way as mechanical switches.  SSRs must also be chosen for AC or DC applications, as they are not universally interchangeable.  Some SSRs require forced air cooling, and may be damaged if not properly ventilated.  Please consult the experts at if you are uncertain about your choice of SSR.





LabView Tutorials

Official Repository


Mechanical Drawing

Wiring Diagrams

Click to Enlarge
Click to Enlarge
Click to Enlarge
Click to Enlarge
Click to Enlarge
Click to Enlarge


Wireless Range Testing Setup

This video tells you the set up that we used to get real world ranges on our wireless communication modules.

This video tells you the set up that we used to get real world ranges on our wireless communication modules.

See More

Finding the Com Port

Learn how to find the COM Port on your windows based computer. You can also use Base Station to find the COM Port of your Relay Controller. Base Station can be downloaded at

Learn how to find the COM Port on your windows based computer. You can also use Base Station to find the COM Port of your Relay Controller. Base Station can be downloaded at

See More

Analog to Digital Converter Introduction

Learn the Basics of Analog to Digital Conversion. Many of our boards have analog to digital inputs directly on the board. These ADC inputs are great for monitoring sensors and controlling relays from software based on these sensor readings. This video will show you how, why, and when to use them.  

Learn the Basics of Analog to Digital Conversion. Many of our boards have analog to digital inputs directly on the board. These ADC inputs are great for monitoring sensors and controlling relays from software based on these sensor readings. This video will show you how, why, and when to use them.  

See More

Buy Now

This product qualifies for:

  • Forum Support (fastest)
  • Direct Email Support
  • Scheduled Phone Support

Special Order Item - Extended Lead Time

This product is considered a special order item and lead times will be increased over our standard lead time of 3-5 business days. Please contact us for lead time estimates.

Product Identification
UPC: 689860072374
Country of Origin: US
HTS Code: 854231
1+ Pieces
10+ Pieces
25+ Pieces
100+ Pieces

Solid State ProXR Lite Relay ControllersChange

900HP-S3B ModemChange

You will need at least one 900HP-S3B Modem to talk to our complete line of 900HP-S3B Wireless Mesh devices. The USB Configuration Adapter is used to change the 900HP-S3B communication module settings for the module that is plugged into your remote device.

Would you like a power supply?Change

NCD Controllers Need Power. Standard NCD Power Supplies use a 2.1mm Barrel Connector with 12VDC (center positive) rated at 1.25 Amps (minimum).


We Customize Just for You!!

NCD offers many custom IoT electronic design services to help tailor our product to your exact needs.  Whether you are looking for custom firmware, circuit board modifications, metal enclosures, or industrial color printing, we can help you with a wide variety of design services.

Custom IoT Electronic Design Services Process

Most of our users purchase off-the-shelf hardware for initial testing.  Once everything is working, they contact us to build a custom solution which may include specialized changes to the board, firmware, connectors, etc.  Custom boards have many advantages such as reduced wiring, easy installation, small size, less power consumption, and in some cases, an overall reduction in product cost.  Custom IoT Electronic Design Services will have your company name and logo on the board as well as the enclosure.

Customized IoT Electronics

NCD engineers can help build a customized solution for your particular application based on the designs you see on our website.  We can combine devices onto a single board, change the shape, or even some of the components to meet your exact needs.  We also provide turn-key metal enclosures with powder coating and full-color printing on the top side starting at just $500 for setup!  We have more than 20 years of experience in electronics design and manufacturing.  All of our products are designed and manufactured in the USA, so we are here to support the products we make.  We only ask that our customers prototype their needs using our existing products before we customize.

Customization Guidelines

  • Custom designs should be based on our existing product because we can’t build rockets or electric cars over here!
  • We do not provide customization services if it involves the introduction of a new or untested technology.
  • Custom engineering fees depend on your requirements, so please contact us for a quote!
  • We maintain ownership of all designs, including our customized designs as they are based on our existing Design.
  • We will only ship the customized product to you or your authorized agents.
  • We have an NDA available if needed.
  • The turn-around time is about 2-3 weeks.
  • We specialize in low-volume designs, no quantity is too small!
  • We have the ability to scale to large volumes as needed.

Getting Started with Product Customization

All you have to do is contact us and we will walk you through the process from beginning to end, based on your individual needs.  Some people are surprised at how fast we finish CAD design (usually a few hours), but keep in mind, we still have to build your design, which takes considerably more time.  When we customize product, here are the general services we provide:

  • We design the circuit board.
  • We communicate with our customers throughout the customization and manufacturing process.
  • We manufacture surface mount stencils and circuit boards.
  • We program our pick and place machines to build your boards.
  • We build a working sample and run it through our wave solder machine.
  • We test your custom IoT solution.
  • Once the design is finalized it won’t be possible to make changes during production (changes cost money and require us to repeat the above processes)
  • Once it meets all your requirements, we will start production as needed.
  • We work with our metal fabricators to design a metal enclosure if required.
  • You work with our artist to print the top side of the enclosure in full color with your company logo if required.

+MORE App customizations

We partnered with Blynk who have developed the +MORE app.  If you are interested in customization to their +MORE app then we're sure you will enjoy working with them as much as we did.  They can customize the user interface +MORE mobile app at your request.

  • Add new functionality and features to the mobile applications and web dashboard
  • Change/ add data visualizations options

Contact them today for custom App Development!

White-labeled mobile apps and dashboard

Blynk the developer of +MORE has a fantastic team of developers eager to help with your IoT applications.  They offer the following services.

We provide white-label IoT infrastructure:

  • Private IoT cloud
  • Branded mobile applications for remote monitoring and control
  • A branded web dashboard to manage fleet of your devices
  • Big Data analysis with actionable insights
  • Development of machine learning algorithms

Contact them today for all of your IoT cloud needs!

©2021 National Control Devices, LLC

Made in the USA
5 Year Warranty
Free Shipping on orders over $100
Free Shipping on orders over $100

To learn something new, take the path that you took yesterday. ~John Burroughs

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