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  • Onboard Open Collector Status LEDs
  • Screw Terminal Connectors
  • Power LEDs
  • 2.1mm Power Connector
  • Optional Power Supply
  • Includes 6″ XR Expansion Cable
  • OC Outputs Allow Control of External Relays and Contactors



About Open Collectors

Open Collector Outputs are used primarily for the purposes of controlling external DC relays and some very small DC solenoids.  An open collector output is different than a relay output.  Open collector outputs allow the user to control the connection of an external device by connecting and disconnecting the ground wire under software control.  To drive an external 12V relay, +12V should be connected to one side of the relay at all times.  The other side of your relay should be connected to our Open Collector output.  Use our open collector outputs to make the connection to ground under software control.  Open Collector outputs are also known as low side drivers (meaning it switches the ground line).  In this way, different devices of different voltages may be controlled, providing all power supplies can share a common ground.  A relay can provide you with a simulated open collector output by simply by connecting one of the relay outputs to your power supply ground.  For wiring diagrams, please see the XR manual page 8.

ProXR Expandability

ProXR Controllers were built with relay expansion in mind. Easily add different types of relays for high-power, signal, general purpose, or solid-state switching.  The XR Expansion Port allows you to also add expansion boards and control up to 256 relays.

Above: A 4-channel ProXR Series Controller (bottom) shown with an 8-channel expansion board attached.
Simply chain the XR Expansion Modules, one after another, to add additional relays to any ProXR board up to 256 relays.

XR Expansion Port

XR Relay Expansion Controllers add a large variety of relay switching capabilities to an existing NCD ProXR series controller.

The XR Expansion Port is used to add banks of external relays to a ProXR Controller equipped with a XR Expansion port.  As we continue to develop new devices, a modular architecture will be implemented, offering the greatest amount of user flexibility.

Controlling XR Expansion Banks

FXR Expansion Boards have no on-board brains. They are entirely reliant on the brains of a “master” ProXR device.  The XR Expansion Modules have many possibilities:

  • Adds up to 256 Relays to a ProXR Series Controllers
  • Mix and Match Relay Types to Suite your Application Needs
  • Choose Between Mechanical and Solid-State Relay Types
  • Choose DPDT Relays for Signal Switching Applications

Linking XR Expansion Boards Together

XR Expansion Controllers consist of a XR Input and XR Output Connector.  Simply connect the XR Output of your ProXR Controller to the XR Input located on the relay expansion board.  Chaining more relays is easy.   Simply connect the XR Output of your ProXR expansion board to the XR Input of your next relay expansion.  Mix and Match different relay types as your application requires.

We always include a 6″ expansion cable with your expansion board.  We can provide longer cables if needed, but it’s important to keep the cabling as short as possible.  Not all users will be able to expand to 256 total relays, as it all depends on the installation, the amount of electrical interference, and the overall cable length.  For best compatibility, the total length of the ProXR controller and all of the expansions and cabling should not exceed 1 or 2 meters.


ProXR vs. ProXR Lite

ProXR controllers include a XR Expansion port.  This controller will plug into the XR expansion port of your ProXR series controller.  ProXR Lite controllers do not include a XR Expansion port; therefore, this expansion will not work with ProXR Lite series controllers.

XR vs. FXR Expansions

XR and FXR expansions are very similar, but are not directly compatible with each other.  The FXR expansion port is an updated version of XR, which includes a right-angle connector to support our metal enclosures.  The FXR cable is also capable of carrying I2C data.  Because of the right-angle connector, the polarity of the cable is not compatible with XR expansions.

Maximum Relay Rating Notes

ProXR is capable of expanding to an absolute maximum of 256 Relays.  In some cases, it may not be possible to control all 256 relays, particularly in applications where high noise levels may be involved.  Experimentation may be required, as it is not possible for us to guarantee all users will be able to utilize all 256 relays in every application.  Noise tends to accumulate when several expansions are connected together.  For best results, the XR expansion cables must be as short as possible.  The typical total length of ProXR and all of its expansions and cabling should not exceed 1 or 2 meters.


Mechanical Drawing

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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
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Free Shipping on orders over $100

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

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