Four Relays Four Inputs 8-Layer Stackable Card for Raspberry Pi

FOUR HEAVY DUTY RELAYS PLUS FOUR UNIVERSAL INPUTS FOR RASPBERRY PI

Drive 8A/240VAC loads and read 3V to 240V, AC or DC, opto-isolated inputs for all your Home or Industrial Automation Projects

Perfect add-on to your project when you have to control large number of heavy duty AC loads and/or you have to read wide range inputs. Stackable to 8 layers, the card can add up to 32 relays to each Raspberry Pi in a very compact form factor. In addition, you can read up to 32 opto-isolated inputs.

Pluggable connectors make the 4-RELAYS card easy to use when multiple cards are stacked up.  All relays have Normal Open and Normal Close contacts and can switch up to 8A/240VAC. 

The optically isolated universal inputs can read AC or DC signals from 3V to 240V. The input connectors have a low voltage port which can read signals between 3V and 24V, and a high voltage port which can read signals between 24V and 240V.

COMPATIBILITY

The card is compatible with all Raspberry Pi versions from Zero to 4. All stacked cards share the I2C bus using only two of the Raspberry Pi’s GPIO pins to manage all eight cards.  This feature leaves the remaining 24 GPIOs available for the user.

POWER REQUIREMENTS

The card needs 5V to operate and can be powered from Raspberry Pi or from it's own 2 pin pluggable connector. The relay coils are also powered from the 5V.  The card draws 10mA with all relays off. Each relay needs about 80 mA to turn on. If power is applied to the 2 pin pluggable connector, no other power supply is needed for the Raspberry Pi.

STACKING MULTIPLE CARDS

Up to eight cards can be stacked on your Raspberry Pi. Each card is identified by jumpers you install to indicate the level in the stack. Cards can be installed in any order. A three position jumper selects the stack level.

For your convenience, two jumpers are provided with each card. 

REVERSE POWER SUPPLY PROTECTION

The board is protected to accidental reverse power supply with a 5.8A, 39 mOhm MOSFET which breaks the ground line if reverse power is applied. 

RESET PUSHBUTTON

Shutting down the Raspberry Pi by turning off the power can result in SD Card failure. To prevent this, a shutdown command needs to be used before power cut-off. But this requires a monitor, keyboard and mouse connected to the Pi. 

A momentary on push button installed at the edge of the board provides a convenient way to shut down the Raspberry Pi. The button is routed to pin 37 (GPIO 26). You need to write a script which monitors this pin, and if pressed for more than a desired time, issues the shut-down command.

• Power Supply: 5V/8A pluggable connector with reverse polarity protection
• On board resettable fuse: 3A
• Opto-isolated Digital Inputs:
• Input Forward Current: Typical 5 mA, maximum 50 mA
• Low Voltage Input Series Resistor: 1.2K
• High Voltage Input Series Resistor: 10K
• Isolation Resistance: Minimum 1012 Ω
• Relays: NO/NC contacts, 8A/240 VAC-24 VDC

Features

• Four RELAYS with Status LEDs and NO/NC contacts
• Four universal opto-isolated inputs with status LEDs
• Eight layer stackable to 32 relays and 32 inputs
• RS485/MODBUS transceiver
• Raspberry Pi reset push button
• Pluggable Connectors 30-16 AWG wires
• Switch loads of up to 8A and 240VAC/24VDC
• Read 3V to 240V AC/DC inputs
• Software self-test
• Command Line
• Python Drivers
• Node-Red node and examples