RPisPLC Digital 24Volt interface

Digital Input/ Output interface card

Digital Input/ Output interface card with 8 inputs 24 V DC and 8 outputs 24 V DC; 0.5 A galvanically isolated, and with LED status indicators.

Digital input/ output modules permit connection of the RPI board to digital signals of the process and the output of digital signals from the RPI board to the process.


Picture 24V IO interface       




16-bit I2C-bus and SMBus I/O port with interrupt

The PCA9555 is a 24-pin CMOS device that provides 16 bits of General Purpose parallel Input/Output (GPIO) expansion for I2C-bus/SMBus applications and was developed to enhance the NXP Semiconductors family of I2C-bus I/O expanders. The improvements include higher drive capability, 5 V I/O tolerance, lower supply current, individual I/O configuration, and smaller packaging. I/O expanders provide a simple solution when additional I/O is needed for ACPI power switches, sensors, push buttons, LEDs, fans, etc.

More about I2C.

PLµX standard pin configuration for PCA9555.

Digital 24 volt IO-interface

Download 24v_8io_interface.tar.gz schematic and PCB.
Created with Eagle PCB Design Software cadsoftusa.
Create your own PCB: eurocircuits

Error found let me know. Thanks in advance.

The Schematic




PLux 24V interface with 8 inputs and 8 outputs

Technical data

Digital Inputs
Number of channels 8
Input voltage 24V
Galvanic isolation: Number of groups 4


Digital Outputs
Output voltage 24V
Output current  0.5A
Number of channels  8
Galvanic isolation: Number of groups 4


Ansi C library for the PCA9555

A simple ansi c library for the PCA9555 I2C Expander.

Download: Ansi C souce file,  Header file.



wo kann man das 24v interface beziehen/kaufen? mfg george hopeman

You have to build the interface card. Download PCB and chematic, go to: https://dciux.eu/?q=download_page. Or download: http://www.dcisite.be/plux.interface/plux_io2.zip

I recently obtained this USB To Buffered Digital I/O from http://www.bcsideas.com/RP0000xxxxN.php. I see that you connected you RPi to your own board. Was this a difficult process? My intention is to communicate to the board over USB Type B connection. I probably need to install the drivers, etc that come with BCSs board from their website in order for it to work. Eventually I would have the RPi hooked up to the board and have the RPi control each device that I have hooked up to the I/O board. Any thoughts or comments on how I might achieve this? I'm a little nervous to connect the power supply to the board then connect the USB type B from the RPi to the board.

I don't think the buffered digital I/O hardware add support for Linux. So you need windows, here I have no experience with it. For controlling, measuring and control I2C or SPI is a better protocol than USB I think. I do not think the Buffered Digital I/O hardware add support for Linux. For controling, measuring and regulating, GNUBLIN offers many modules (like motor controler, relay, input, output, analog to digital, digital to analog, temperature sensor and so on) to create very fast a prototype. http://gnublin.embedded-projects.net/all/ Create your own PCB: http://www.eurocircuits.com/pcb-proto-the-pcb-prototype-service-from-eurocircuits

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