Relay 5 Click

How does it work?

Relay 5 Click is based on three J1031C3VDC.15S, a high-current single-pole double-throw (SPDT) signal relays from CIT Relay and Switch, controlled in a very simple way through a port expander from NXP Semiconductors, the PCA9538A. The J1031C3VDC.15S relay is well known for its reliability and durability, high sensitivity, and low coil power consumption housed in a small package with PC pin mounting. Despite its size (12.5×7.5×10 millimeters (LxWxH)), the J1031C3VDC relay can withstand up to 2A and 125VAC/60VDC maximum. These relays are designed to easily activate their coils by relatively low currents and voltages, making them a perfect choice that any MCU can control. Besides, their durability is impressive, with over 5M of mechanical life cycles.

The contact configuration of the J1031C3VDC.15S is a single-pole double-throw (SPDT), meaning it has one pole and two throws. Based on the default position of the pole, one throw is considered normally open (NO) while the other is normally closed (NC), which is, in this case, its default position. When the coil is energized, it will attract the internal switching elements similar to a switch. For this purpose, the Relay 5 Click has three terminals for each relay that are adequately labeled. In addition, every relay has its status LED (REL1-3) for visual status presentation.

As mentioned, the relays are not directly driven by the host MCU but by the PCA9538A, a low-voltage 8-bit I/O port with interrupt and reset from NXP Semiconductors. This I/O expander provides a simple solution when additional I/Os are needed while keeping interconnections to a minimum. The Relay 5 Click uses the PCA9538A and 2-Wire I2C interface to communicate with the host MCU. The PCA9538A supports a fast mode of up to 400KHz of clock frequency. The I2C Address can be selected via the ADDR SEL jumpers, with 0 selected by default. The expander can be reset over the RST pin with active LOW, thus setting the registers to their default values without the need to power it off.

This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the VCC SEL jumper. This way, both 3.3V and 5V capable MCUs can use the communication lines properly. However, the Click board™ comes equipped with a library containing easy-to-use functions and an example code that can be used, as a reference, for further development.

Specifications

Pinout diagram

This table shows how the pinout on Relay 5 Click corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns).

Notes	Pin					Pin	Notes
	NC	1	AN	PWM	16	NC
Reset	RST	2	RST	INT	15	NC
	NC	3	CS	RX	14	NC
	NC	4	SCK	TX	13	NC
	NC	5	MISO	SCL	12	SCL	I2C Clock
	NC	6	MOSI	SDA	11	SDA	I2C Dlock
Power Supply	3.3V	7	3.3V	5V	10	5V	Power Supply
Ground	GND	8	GND	GND	9	GND	Ground

Onboard settings and indicators

Relay 5 Click electrical specifications

Software Support

We provide a library for the Relay 5 Click as well as a demo application (example), developed using MIKROE compilers. The demo can run on all the main MIKROE development boards.

Package can be downloaded/installed directly from NECTO Studio Package Manager (recommended), downloaded from our LibStock™ or found on Mikroe github account.

Library Description

This library contains API for Relay 5 Click driver.

Key functions

• relay5_set_relay1_open This function sets the relay 1 to normally open state by setting the RL1 pin to low logic level.

• relay5_set_relay1_close This function sets the relay 1 to normally close state by setting the RL1 pin to high logic level.

• relay5_switch_relay1 This function switches the relay 1 state by toggling the RL1 pin logic level.

Example Description

This example demonstrates the use of Relay 5 Click board™ by toggling the relays state.

void application_task ( void ) 
 { 
     relay5_set_relay1_open ( &relay5 ); 
     log_printf( &logger, " Relay 1 set to normally open statern" ); 
     relay5_set_relay2_close ( &relay5 ); 
     log_printf( &logger, " Relay 2 set to normally close statern" ); 
     relay5_set_relay3_open ( &relay5 ); 
     log_printf( &logger, " Relay 3 set to normally open staternn" ); 
     Delay_ms ( 5000 ); 

     relay5_set_relay1_close ( &relay5 ); 
     log_printf( &logger, " Relay 1 set to normally close statern" ); 
     relay5_set_relay2_open ( &relay5 ); 
     log_printf( &logger, " Relay 2 set to normally open statern" ); 
     relay5_set_relay3_close ( &relay5 ); 
     log_printf( &logger, " Relay 3 set to normally close staternn" ); 
     Delay_ms ( 5000 ); 
 }

The full application code, and ready to use projects can be installed directly from NECTO Studio Package Manager (recommended), downloaded from our LibStock™ or found on Mikroe github account.

Other Mikroe Libraries used in the example:

• MikroSDK.Board
• MikroSDK.Log
• Click.Relay5

Additional notes and informations

Depending on the development board you are using, you may need USB UART click, USB UART 2 Click or RS232 Click to connect to your PC, for development systems with no UART to USB interface available on the board. UART terminal is available in all MIKROE compilers.

mikroSDK

This Click board™ is supported with mikroSDK – MIKROE Software Development Kit, that needs to be downloaded from the LibStock and installed for the compiler you are using to ensure proper operation of mikroSDK compliant Click board™ demo applications.

For more information about mikroSDK, visit the official page.