Eight 4-20mA Analog Outputs for Raspberry Pi Back Panel top

8-MOSFETS with PWM on Raspberry Pi Back Panel enclosed

Eight 4-20mA Analog Outputs for Raspberry Pi Back Panel bottom

8-MOSFETS with PWM on Raspberry Pi Back Panel open frame

Eight 4-20mA Analog Outputs for Raspberry Pi Back Panel installed

SKU: SM-P-140

Eight 4-20mA Analog Outputs, Source/Sync for Raspberry Pi Back Panel

Name: Eight 4-20mA Analog Outputs, Source/Sync for Raspberry Pi Back Panel
Brand: Sequent Microsystems
SKU: SM-P-140
Price: 100.0 USD
Availability: OutOfStock

Industrial-grade 4–20mA analog output card with 8 channels, source or sink mode. Stackable with Back Panel for Raspberry Pi automation systems.

Coming soon

$100.00

Product variants

The Eight 4–20mA Analog Outputs for Raspberry Pi Back Panel features eight 4–20mA outputs routed to the Back Panel terminal blocks. Designed for maximum flexibility, each output can be individually configured as either a source or a sink.

Seamlessly integrated with the Raspberry Pi Back Panel, the card supports MODBUS RTU over RS485, OpenPLC, and CODESYS.

FEATURES

Key Features

Eight 4-20mA Analog Output Channels
Each channel can be individually programmable as source or sink
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
Input and output 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 Eight 4–20mA Analog Outputs I/O 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.

Each output can be configured in software as either source or sink—no jumpers or DIP switches required.

Like all HOP cards, the Eight 4–20mA Analog Outputs 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 output, also indicating whether the output is in source or sink mode.

An RS485 port enables communication with external PLCs or industrial controllers using the industry-standard MODBUS RTU protocol.

Power Requirements

The Eight Relays Eight Inputs card is powered via the Back Panel power connector.

Outputs are power from the 24V supply and can draw up to 200mA
The local processor is powered from the 5V rail through a 3.3V LDO regulator and consumes 10 mA.

Error Processing

One pin on the spring-loaded terminal block of the Back Panel is reserved for signaling an error condition. The user can connect this pin to an external contact of their choice. When the error signal is activated, the Eight 4-20mA Analog Outputs card automatically resets all outputs to a predefined default state.

GPIO Pinput

The optically isolated inputs are routed through the 2x20 GPIO connector to the corresponding terminal block on the Back Panel.

CUT: If the watchdog is enabled and the Raspberry Pi fails to access the I2C port within the preset time, the CUT line is activated, disconnecting power to the Raspberry Pi for 10 seconds.

SDA, SCL: I²C communication lines used for data (SDA) and clock (SCL) exchange between the Back Panel and the Raspberry Pi.

ID0-2: Stack level allocation pins. The stack level is automatically determined by the slot into which the card is inserted on the Back Panel.

INT: Interrupt line. This line can be manually triggered or programmed to interrupt the Raspberry Pi based on a specific input value or sequence.

IO18: This pin is a dry contact to ground and can be activated by an external contact wired to the Back Panel terminal block. When triggered, it resets all outputs to a predefined default states.

IO01-IO16: Eight 4-20mA Outputs: Odd-numbered inputs are routed to the high side, and even-numbered inputs to the low side.

IO01-IO02: Input #1

IO03-IO04: Input #2

IO05-IO06: Input #3

IO07-IO08: Input #4

IO09-IO10: Input #5

IO11-IO12: Input #6

IO13-IO14: Input #7

IO15-IO16: Input #8

BACK PANEL TERMINAL BLOCK PINOUT

Eight Relays Eight Inputs Back Panel Terminal Block Connections

DOT MATRIX DISPLAY

Eight Relays Eight Inputs for Raspberry Pi Back Panel - OLED Display

The Eight 4-20mA Analog Outputs card includes a 128 × 32 dot-matrix display driven by the on-board processor. It can show status information, self-test results, and error messages. At power up it displays the card name and the I2C address.

ELECTRICAL SPECIFICATIONS

Power Supply: 5V 10mA; 24V 120mA Back Panel provided
Source/Sync outputs: 14bit PWM
Relays 5-8: N.O. contacts 8A/48VAC/24VDC

MECHANICAL SPECIFICATIONS

Eight Relays Eight Inputs for Raspberry Pi Back Panel Mechanical

DOWNLOADS

Hardware Schematic V1.0

2D DXF Mechanical

3D STEP Model

3D Printable Enclosure

SOFTWARE

Command Line Drivers

Python Libraries

CODESYS Driver

OpenPLC Module

QUICK START

Plug the Eight 4-20mA Analog Outputs 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/8analog1-rpi.git
~$ cd /home/pi/8analog1-rpi
~/8relind-rpi$ sudo make install
~/8relind-rpi$ 8analog1

The program will respond with a list of available commands.

FAQ

Q: What is the function of this card?
A: It provides eight programmable 4–20mA analog outputs, each configurable as a current source or sink, for industrial control applications.

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: How do I configure outputs as source or sink?
A: Output mode is configured in software—no need for jumpers or DIP switches.

Q: What software platforms are supported?
A: The Eight 4-20mA Analog Outputs 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 output activity and mode.

Q: How is the card powered?
A: Power is supplied through the 24V 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.

Q: What types of loads can the outputs drive?
A: The card is designed to drive standard industrial 4–20mA current loops in both sourcing and sinking configurations. Refer to the datasheet for load specifications.