







8-Channel Universal Input Card for Raspberry Pi Back Panel
8-Channel Universal Input Card: 0-3.3V, 0-10V, 4-20mA, 1K/10K Thermistors, Dry Contact/Counters
The 8-Channel Universal Input Card for Raspberry Pi Back Panel features eight universal, analog and digital inputs routed to the Back Panel terminal blocks.
Seamlessly integrated with the Raspberry Pi Back Panel, the card supports Command Line, MODBUS RTU over RS485, OpenPLC, and CODESYS.
FEATURES
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Eight Universal Input Channels
Each input can be software configured to read 0-3.3V, 0-10V, 4-20mA, 1K/10K Thermistors, Dry Contact or Counter inputs -
Seamless Raspberry Pi Integration
Plugs directly into the Raspberry Pi Back Panel — no additional wiring or hardware needed. -
Expandable Stack Design
Stack up to 8 identical modules horizontally for larger projects. -
MODBUS Support via RS485
Integrated RS485 port allows MODBUS RTU communication for easy industrial integration. -
Real-Time Status LEDs
LED indicators provide immediate visual feedback. -
Built-in OLED Display
128×32 dot matrix screen for displaying system status, messages, or sensor values. -
Cross-Platform Software Support
Includes Python library and command-line tools for rapid development. -
OpenPLC & CODESYS Compatible
Industrial-grade compatibility with both OpenPLC and CODESYS environments. -
No Export Restrictions
ECCN classification EAR99 — freely exportable under U.S. regulations.
DESCRIPTION
Part of the HOP (Hardware On Panel) family developed by Sequent Microsystems, the 8-Channel Universal Input Card is designed to integrate seamlessly with the Raspberry Pi Back Panel. Up to eight HOP cards—of any type—can be installed on a single Back Panel, offering maximum flexibility for industrial automation applications. Multiple Back Panels can be connected horizontally to support larger projects.
Like all HOP cards, the 8-Channel Universal Input Card features 18 LED indicators. The power LED blinks when power is applied and the local processor is operational. An error LED illuminates when the dedicated PANIC pin on the Back Panel terminal block is activated. Sixteen additional LEDs display the real-time status of each input.
An RS485 port enables communication with external PLCs or industrial controllers using the industry-standard MODBUS RTU protocol.
Power Requirements
The card is powered via the Back Panel power connector.
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The local processor is powered from the 5V rail through a 3.3V LDO regulator and consumes 10 mA.


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Power Supply: 5V 10mA Back Panel provided

DOWNLOADS
Hardware Schematic V1.0
3D STEP Model
3D Printable Enclosure
SOFTWARE
Command Line Drivers
Python Libraries
CODESYS Driver
OpenPLC Module
QUICK START
- Plug the 8-Channel Universal Input Card on the Back Panel for Raspberry Pi and power up the system.
- Enable I2C communication on Raspberry Pi using raspi-config.
- Install the software from github.com:
- git clone https://github.com/SequentMicrosystems/sequent-cli.git
- cd /home/pi/sequent-cli
- sudo make install
- sequent-cli univ-in -h
FAQ
Q: What is the function of this card?
A: It provides eight programmable inputs. Each input can be sofware configured to read 0-3.3V, 0-10V, 4-20mA, 10K/10K Thermistors, Dry Contact or Counter digital signals.
Q: Can I mix this card with other HOP cards on the same Back Panel?
A: Yes, up to eight HOP cards of any type can be installed on a single Back Panel, allowing flexible I/O combinations.
Q: What software platforms are supported?
A: The card supports MODBUS RTU over RS485, and is compatible with OpenPLC, CODESYS, and Sequent’s command-line utilities.
Q: What do the LEDs indicate?
A: One LED indicates power and processor health, one signals an error (via the PANIC pin), and 16 LEDs display real-time input activity.
Q: How is the card powered?
A: Power is supplied through the 5V rail of the Raspberry Pi Back Panel.
Q: Is this card stackable?
A: Yes. It can be stacked with up to seven other HOP cards per Back Panel. Additional Back Panels can be chained for larger systems.
Q: Can I use this card without a Raspberry Pi?
A: Yes, via RS485 and MODBUS RTU, the card can be controlled by an external PLC or industrial controller without a Raspberry Pi.
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