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The EXP-RELAY expansion board is an output module that features 6 General Purpose Relays rated at 6A 250VAC. The board enables the developers to control motors, fuel pump, industrial applications where control of high voltages and currents is intended, controlling large power loads.

Zerynth expansion boards work seamlessly with all of Zerynth Development boards, combined they can act as a Development Board for prototyping a Product, and a core for industrial applications.

Device Summary

  • 6x General Purpose Relays rated at 6A 250VAC

Resources and Documents

Software Library

For more information on the EXP-RELAY Library as software Library, features, functions and examples Please check this Link

Pin Mapping

Rotart and Standard switches

For information on the switches and other hardware details, Please refer to the User manual of the board


Power to the EXP-RELAY is supplied directly by the ZM1-DB.


The modular expansion system uses the Z-Bus. The Z-Bus is an efficient, powerful standard for connecting and prototyping different sensors and devices. The Z-Bus is using the CN1 pin header (20x2) exposing the following:

  • 16 GPIO pins.
  • 4 interrupt pins.
  • 2 USART/UART instances with full support (TX,RX,RTS,CTS)
  • I2C, SPI support.
  • 5V, 3.3 V output pins.
  • Enable pin for controlling the power to attached expansion boards.


The development boards support up to 3 attached expansion boards.

Expansion boards vary in features and functionality. Currently, Zerynth offers expansion boards for :

  • EXP-AIN: Expansion board with 8 Industrial analog input channels
  • EXP-CONNECT: GSM-NB-IoT and GPS enabled expansion module.
  • EXP-IO: Industrial input/output board with 4 solid-state relays, 2 analog channels (4-20mA/0-10V/NTC/current clamp) channels, 2 opto-isolated digital inputs
  • EXP-RELAY: Relay board with 6 Electromechanical power relays rated 6A 250VAC.
  • EXP-SER: Serial Communication board with : CAN, RS232 and RS485 interfaces.
  • EXP-PROTO: Prototyping board for connecting and testing different types of sensors and devices.