WL-MIO Multipurpose I/O Process Controller

Widgetlords Electronics has launched a new product line called the WL-MIO.

This product line is based on a 8 position backplane, hot swap I/O modules, and uses a Raspberry Pi 4 Model B as the main controller.


Widgetlords has created a dedicated website wlmio.com for the WL-MIO that has complete descriptions, application notes, field wiring diagrams, demo software and more. Just like the PI-SPI and PI-SPI-DIN series of products, there is an open source GitHub repository of all source code and demo code.

Here are the main features of the WL-MIO:

  • Raspberry Pi 4 Model B as the main controller
  • CAN bus communication between modules
  • Up to 16 backplanes, 128 modules, and 300' (max) CAN bus length
  • Complete selection of I/O modules available
    • Analog Input 4 channel SDAFE (4-20 mA, 0-5 VDC and 0-10 VDC Inputs)
    • Digital Input 4 Channel Discrete, Frequency and Pulse Counter
    • Thermistor 8 Channel Input
    • Analog Output 4 Channel 4-20 mA
    • Analog Output 4 Channel 0-10 VDC
    • Relay Output 4 Channel SPDT 2A
    • Power Supply 5 VDC @ 4 A
    • Raspberry Pi Carrier Cards with RS485 and Optional HART modem
  • Numbered and colored terminal blocks for easy module identification
  • DIN Rail mountable
  • Module to Module Isolation
  • Each module has an ARM processor and memory for identification and calibration storage
  • Each module has a QR code that is field readable for wiring and module information.

Two Backplane versions are available - the basic DIN rail mount (VPE-6000-N) and the metal enclosure DIN rail mount, as shown above with the cover removed.

The Backplanes have no active parts, only the terminal blocks, sockets, plastic card guides, and Backplane ID jumpers. The enclosed version has plastic backing plates giving the assembly and IP20 rating.


Here is the block diagram for the WL-MIO backplane:

Wiring Diagram for Two Backplanes:


Scalable up to 16 Backplanes:






Here is the block diagram for the VPE-6040 4 Channel SDAFE (Software Defined Analog Front End) that shows a typical module's power supply, CAN bus drivers, ARM processor and I/O section:


Sample Python Demo code for the above can be found here.

Starter kits are available, with and without the Raspbery Pi 4 Model B module.






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