How does it work?

LEM Click is based on the LTS 6-NP, a current transducer from Lem. It acts as a transformer with 2000 turns as a secondary coil and a load resistance of 2kΩ and above. The primary coil is a wire of the load itself, threaded through the middle of the current transducer while fully isolated and galvanic separated from the secondary coil. The LTS 6-NP uses the Hall effect to output the values regarding the current that passes through. The sensor output passes to the MCP607, a micropower CMOS operational amplifier from Microchip. It is a unity-gain stable, low offset voltage OpAmp that includes rail-to-rail output, swing capability, and low input bias current.

The output values from the operational amplifier pass to the MCP3201, a 12-bit analog-to-digital converter with SPI serial interface from Microchip. The MCP3201 provides a single pseudo-differential input features on-chip, sample and hold, a maximum sampling rate of up to 100ksps, and more. The MCP3201 gets the 2.048V reference voltage from the MAX6106, a low-cost, micropower, low-dropout, high-output-current voltage reference from Analog Devices.

The LEM Click uses the 3-Wire SPI serial interface of the MCP3201 to communicate with the host MCU supporting SPI 0 and SPI 3 modes with a frequency of up to 1.6MHz. The voltage amplified through the MCP607 can be directly monitored through the AN pin of the mikroBUS™ socket, which is useful if the host MCU has a higher ADC resolution.

This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the PWR 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 LEM Click corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns).

Notes	Pin					Pin	Notes
Analog Input	AN	1	AN	PWM	16	NC
	NC	2	RST	INT	15	NC
SPI Chip Select	CS	3	CS	RX	14	NC
SPI Clock	SCK	4	SCK	TX	13	NC
SPI Data OUT	SDO	5	MISO	SCL	12	NC
	NC	6	MOSI	SDA	11	NC
Power Supply	3.3V	7	3.3V	5V	10	5V	Power Supply
Ground	GND	8	GND	GND	9	GND	Ground

Onboard settings and indicators

LEM Click electrical specifications

Software Support

We provide a library for the LEM 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 LEM Click driver.

Key functions

• Function is used to read current in amperes or milliamperes.

Example Description

Demo app measures and displays current by using LEM click board.

 void application_task ( void ) 
 { 
     current = lem_get_current( &lem, LEM_MILIAMP_COEF ); 

     log_printf( &logger, " Current : %.2f mA rn", current ); 
     log_printf( &logger, "---------------------rn" ); 
     Delay_ms( 1000 ); 
 }

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.Lem

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. To ensure proper operation of mikroSDK compliant Click board™ demo applications, mikroSDK should be downloaded from the LibStock and installed for the compiler you are using.

For more information about mikroSDK, visit the official page.