C/C++ - Energy Monitor Bricklet

This is the description of the C/C++ API bindings for the Energy Monitor Bricklet. General information and technical specifications for the Energy Monitor Bricklet are summarized in its hardware description.

An installation guide for the C/C++ API bindings is part of their general description.

Examples

The example code below is Public Domain (CC0 1.0).

Simple

Download (example_simple.c)

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#include <stdio.h>

#include "ip_connection.h"
#include "bricklet_energy_monitor.h"

#define HOST "localhost"
#define PORT 4223
#define UID "XYZ" // Change XYZ to the UID of your Energy Monitor Bricklet

int main(void) {
    // Create IP connection
    IPConnection ipcon;
    ipcon_create(&ipcon);

    // Create device object
    EnergyMonitor em;
    energy_monitor_create(&em, UID, &ipcon);

    // Connect to brickd
    if(ipcon_connect(&ipcon, HOST, PORT) < 0) {
        fprintf(stderr, "Could not connect\n");
        return 1;
    }
    // Don't use device before ipcon is connected

    // Get current Energy Data
    int32_t voltage, current, energy, real_power, apparent_power, reactive_power;
    uint16_t power_factor, frequency;
    if(energy_monitor_get_energy_data(&em, &voltage, &current, &energy, &real_power,
                                      &apparent_power, &reactive_power, &power_factor,
                                      &frequency) < 0) {
        fprintf(stderr, "Could not get Energy Data, probably timeout\n");
        return 1;
    }

    printf("Voltage: %f V\n", voltage/100.0);
    printf("Current: %f A\n", current/100.0);
    printf("Energy: %f Wh\n", energy/100.0);
    printf("Real Power: %f h\n", real_power/100.0);
    printf("Apparent Power: %f VA\n", apparent_power/100.0);
    printf("Reactive Power: %f VAR\n", reactive_power/100.0);
    printf("Power Factor: %f\n", power_factor/1000.0);
    printf("Frequency: %f Hz\n", frequency/100.0);

    printf("Press key to exit\n");
    getchar();
    energy_monitor_destroy(&em);
    ipcon_destroy(&ipcon); // Calls ipcon_disconnect internally
    return 0;
}

Callback

Download (example_callback.c)

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#include <stdio.h>

#include "ip_connection.h"
#include "bricklet_energy_monitor.h"

#define HOST "localhost"
#define PORT 4223
#define UID "XYZ" // Change XYZ to the UID of your Energy Monitor Bricklet

// Callback function for Energy Data callback
void cb_energy_data(int32_t voltage, int32_t current, int32_t energy, int32_t real_power,
                    int32_t apparent_power, int32_t reactive_power, uint16_t power_factor,
                    uint16_t frequency, void *user_data) {
    (void)user_data; // avoid unused parameter warning

    printf("Voltage: %f V\n", voltage/100.0);
    printf("Current: %f A\n", current/100.0);
    printf("Energy: %f Wh\n", energy/100.0);
    printf("Real Power: %f h\n", real_power/100.0);
    printf("Apparent Power: %f VA\n", apparent_power/100.0);
    printf("Reactive Power: %f VAR\n", reactive_power/100.0);
    printf("Power Factor: %f\n", power_factor/1000.0);
    printf("Frequency: %f Hz\n", frequency/100.0);
    printf("\n");
}

int main(void) {
    // Create IP connection
    IPConnection ipcon;
    ipcon_create(&ipcon);

    // Create device object
    EnergyMonitor em;
    energy_monitor_create(&em, UID, &ipcon);

    // Connect to brickd
    if(ipcon_connect(&ipcon, HOST, PORT) < 0) {
        fprintf(stderr, "Could not connect\n");
        return 1;
    }
    // Don't use device before ipcon is connected

    // Register Energy Data callback to function cb_energy_data
    energy_monitor_register_callback(&em,
                                     ENERGY_MONITOR_CALLBACK_ENERGY_DATA,
                                     (void (*)(void))cb_energy_data,
                                     NULL);

    // Set period for Energy Data callback to 1s (1000ms)
    energy_monitor_set_energy_data_callback_configuration(&em, 1000, false);

    printf("Press key to exit\n");
    getchar();
    energy_monitor_destroy(&em);
    ipcon_destroy(&ipcon); // Calls ipcon_disconnect internally
    return 0;
}

API

Every function of the C/C++ bindings returns an integer which describes an error code. Data returned from the device, when a getter is called, is handled via output parameters. These parameters are labeled with the ret_ prefix.

Possible error codes are:

  • E_OK = 0
  • E_TIMEOUT = -1
  • E_NO_STREAM_SOCKET = -2
  • E_HOSTNAME_INVALID = -3
  • E_NO_CONNECT = -4
  • E_NO_THREAD = -5
  • E_NOT_ADDED = -6 (unused since C/C++ bindings version 2.0.0)
  • E_ALREADY_CONNECTED = -7
  • E_NOT_CONNECTED = -8
  • E_INVALID_PARAMETER = -9
  • E_NOT_SUPPORTED = -10
  • E_UNKNOWN_ERROR_CODE = -11
  • E_STREAM_OUT_OF_SYNC = -12
  • E_INVALID_UID = -13
  • E_NON_ASCII_CHAR_IN_SECRET = -14

as defined in ip_connection.h.

All functions listed below are thread-safe.

Basic Functions

void energy_monitor_create(EnergyMonitor *energy_monitor, const char *uid, IPConnection *ipcon)
Parameters:
  • energy_monitor – Type: EnergyMonitor *
  • uid – Type: const char *
  • ipcon – Type: IPConnection *

Creates the device object energy_monitor with the unique device ID uid and adds it to the IPConnection ipcon:

EnergyMonitor energy_monitor;
energy_monitor_create(&energy_monitor, "YOUR_DEVICE_UID", &ipcon);

This device object can be used after the IP connection has been connected (see examples above).

void energy_monitor_destroy(EnergyMonitor *energy_monitor)
Parameters:
  • energy_monitor – Type: EnergyMonitor *

Removes the device object energy_monitor from its IPConnection and destroys it. The device object cannot be used anymore afterwards.

int energy_monitor_get_energy_data(EnergyMonitor *energy_monitor, int32_t *ret_voltage, int32_t *ret_current, int32_t *ret_energy, int32_t *ret_real_power, int32_t *ret_apparent_power, int32_t *ret_reactive_power, uint16_t *ret_power_factor, uint16_t *ret_frequency)
Parameters:
  • energy_monitor – Type: EnergyMonitor *
Output Parameters:
  • ret_voltage – Type: int32_t, Range: [-231 to 231 - 1]
  • ret_current – Type: int32_t, Range: [-231 to 231 - 1]
  • ret_energy – Type: int32_t, Range: [-231 to 231 - 1]
  • ret_real_power – Type: int32_t, Range: [-231 to 231 - 1]
  • ret_apparent_power – Type: int32_t, Range: [-231 to 231 - 1]
  • ret_reactive_power – Type: int32_t, Range: [-231 to 231 - 1]
  • ret_power_factor – Type: uint16_t, Range: [0 to 216 - 1]
  • ret_frequency – Type: uint16_t, Range: [0 to 216 - 1]
Returns:
  • error_code – Type: int

Returns all of the measurements that are done by the Energy Monitor Bricklet.

  • Voltage (V): Voltage RMS with a resolution of 10mV (example: 230.05V = 23005)
  • Current (A): Current RMS with a resolution of 10mA (example: 1.42A = 142)
  • Energy (Wh): Energy (integrated over time) with a resolution of 10mWh (example: 1.1kWh = 110000)
  • Real Power (W): Real Power with a resolution of 10mW (example: 1234.56W = 123456)
  • Apparent Power (VA): Apparent Power with a resolution of 10mVA (example: 1234.56VA = 123456)
  • Reactive Power (VAR): Reactive Power with a resolution of 10mVAR (example: 1234.56VAR = 123456)
  • Power Factor: Power Factor with a resolution of 1/1000 (example: PF 0.995 = 995)
  • Frequency (Hz): AC Frequency of the mains voltage with a resolution of 1/100 Hz (example: 50Hz = 5000)

The frequency is recalculated every 6 seconds.

All other values are integrated over 10 zero-crossings of the voltage sine wave. With a standard AC mains voltage frequency of 50Hz this results in a 5 measurements per second (or an integration time of 200ms per measurement).

If no voltage transformer is connected, the Bricklet will use the current waveform to calculate the frequency and it will use an integration time of 10 zero-crossings of the current waveform.

int energy_monitor_reset_energy(EnergyMonitor *energy_monitor)
Parameters:
  • energy_monitor – Type: EnergyMonitor *
Returns:
  • error_code – Type: int

Sets the energy value (see energy_monitor_get_energy_data()) back to 0Wh.

int energy_monitor_get_waveform(EnergyMonitor *energy_monitor, int16_t *ret_waveform, uint16_t *ret_waveform_length)
Parameters:
  • energy_monitor – Type: EnergyMonitor *
Output Parameters:
  • ret_waveform – Type: int16_t[1536], Range: [-215 to 215 - 1]
  • ret_waveform_length – Type: uint16_t
Returns:
  • error_code – Type: int

Returns a snapshot of the voltage and current waveform. The values in the returned array alternate between voltage and current. The data from one getter call contains 768 data points for voltage and current, which correspond to about 3 full sine waves.

The voltage is given with a resolution of 100mV and the current is given with a resolution of 10mA.

This data is meant to be used for a non-realtime graphical representation of the voltage and current waveforms.

int energy_monitor_get_transformer_status(EnergyMonitor *energy_monitor, bool *ret_voltage_transformer_connected, bool *ret_current_transformer_connected)
Parameters:
  • energy_monitor – Type: EnergyMonitor *
Output Parameters:
  • ret_voltage_transformer_connected – Type: bool
  • ret_current_transformer_connected – Type: bool
Returns:
  • error_code – Type: int

Returns true if a voltage/current transformer is connected to the Bricklet.

int energy_monitor_set_transformer_calibration(EnergyMonitor *energy_monitor, uint16_t voltage_ratio, uint16_t current_ratio, int16_t phase_shift)
Parameters:
  • energy_monitor – Type: EnergyMonitor *
  • voltage_ratio – Type: uint16_t, Range: [0 to 216 - 1]
  • current_ratio – Type: uint16_t, Range: [0 to 216 - 1]
  • phase_shift – Type: int16_t, Range: [-215 to 215 - 1]
Returns:
  • error_code – Type: int

Sets the transformer ratio for the voltage and current transformer in 1/100 form.

Example: If your mains voltage is 230V, you use 9V voltage transformer and a 1V:30A current clamp your voltage ratio is 230/9 = 25.56 and your current ratio is 30/1 = 30.

In this case you have to set the values 2556 and 3000 for voltage ratio and current ratio.

The calibration is saved in non-volatile memory, you only have to set it once.

By default the voltage ratio is set to 1923 and the current ratio is set to 3000.

Set the phase shift to 0. It is for future use and currently not supported by the Bricklet.

int energy_monitor_get_transformer_calibration(EnergyMonitor *energy_monitor, uint16_t *ret_voltage_ratio, uint16_t *ret_current_ratio, int16_t *ret_phase_shift)
Parameters:
  • energy_monitor – Type: EnergyMonitor *
Output Parameters:
  • ret_voltage_ratio – Type: uint16_t, Range: [0 to 216 - 1]
  • ret_current_ratio – Type: uint16_t, Range: [0 to 216 - 1]
  • ret_phase_shift – Type: int16_t, Range: [-215 to 215 - 1]
Returns:
  • error_code – Type: int

Returns the transformer calibration as set by energy_monitor_set_transformer_calibration().

int energy_monitor_calibrate_offset(EnergyMonitor *energy_monitor)
Parameters:
  • energy_monitor – Type: EnergyMonitor *
Returns:
  • error_code – Type: int

Calling this function will start an offset calibration. The offset calibration will integrate the voltage and current waveform over a longer time period to find the 0 transition point in the sine wave.

The Bricklet comes with a factory-calibrated offset value, you should not have to call this function.

If you want to re-calibrate the offset we recommend that you connect a load that has a smooth sinusoidal voltage and current waveform. Alternatively you can also short both inputs.

The calibration is saved in non-volatile memory, you only have to set it once.

Advanced Functions

int energy_monitor_get_api_version(EnergyMonitor *energy_monitor, uint8_t ret_api_version[3])
Parameters:
  • energy_monitor – Type: EnergyMonitor *
Output Parameters:
  • ret_api_version – Type: uint8_t[3], Range: [0 to 255]
Returns:
  • error_code – Type: int

Returns the version of the API definition (major, minor, revision) implemented by this API bindings. This is neither the release version of this API bindings nor does it tell you anything about the represented Brick or Bricklet.

int energy_monitor_get_response_expected(EnergyMonitor *energy_monitor, uint8_t function_id, bool *ret_response_expected)
Parameters:
  • energy_monitor – Type: EnergyMonitor *
  • function_id – Type: uint8_t, Range: See constants
Output Parameters:
  • ret_response_expected – Type: bool
Returns:
  • error_code – Type: int

Returns the response expected flag for the function specified by the function ID parameter. It is true if the function is expected to send a response, false otherwise.

For getter functions this is enabled by default and cannot be disabled, because those functions will always send a response. For callback configuration functions it is enabled by default too, but can be disabled by energy_monitor_set_response_expected(). For setter functions it is disabled by default and can be enabled.

Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is send and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For function_id:

  • ENERGY_MONITOR_FUNCTION_RESET_ENERGY = 2
  • ENERGY_MONITOR_FUNCTION_SET_TRANSFORMER_CALIBRATION = 5
  • ENERGY_MONITOR_FUNCTION_CALIBRATE_OFFSET = 7
  • ENERGY_MONITOR_FUNCTION_SET_ENERGY_DATA_CALLBACK_CONFIGURATION = 8
  • ENERGY_MONITOR_FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
  • ENERGY_MONITOR_FUNCTION_SET_STATUS_LED_CONFIG = 239
  • ENERGY_MONITOR_FUNCTION_RESET = 243
  • ENERGY_MONITOR_FUNCTION_WRITE_UID = 248
int energy_monitor_set_response_expected(EnergyMonitor *energy_monitor, uint8_t function_id, bool response_expected)
Parameters:
  • energy_monitor – Type: EnergyMonitor *
  • function_id – Type: uint8_t, Range: See constants
  • response_expected – Type: bool
Returns:
  • error_code – Type: int

Changes the response expected flag of the function specified by the function ID parameter. This flag can only be changed for setter (default value: false) and callback configuration functions (default value: true). For getter functions it is always enabled.

Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is send and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For function_id:

  • ENERGY_MONITOR_FUNCTION_RESET_ENERGY = 2
  • ENERGY_MONITOR_FUNCTION_SET_TRANSFORMER_CALIBRATION = 5
  • ENERGY_MONITOR_FUNCTION_CALIBRATE_OFFSET = 7
  • ENERGY_MONITOR_FUNCTION_SET_ENERGY_DATA_CALLBACK_CONFIGURATION = 8
  • ENERGY_MONITOR_FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
  • ENERGY_MONITOR_FUNCTION_SET_STATUS_LED_CONFIG = 239
  • ENERGY_MONITOR_FUNCTION_RESET = 243
  • ENERGY_MONITOR_FUNCTION_WRITE_UID = 248
int energy_monitor_set_response_expected_all(EnergyMonitor *energy_monitor, bool response_expected)
Parameters:
  • energy_monitor – Type: EnergyMonitor *
  • response_expected – Type: bool
Returns:
  • error_code – Type: int

Changes the response expected flag for all setter and callback configuration functions of this device at once.

int energy_monitor_get_spitfp_error_count(EnergyMonitor *energy_monitor, uint32_t *ret_error_count_ack_checksum, uint32_t *ret_error_count_message_checksum, uint32_t *ret_error_count_frame, uint32_t *ret_error_count_overflow)
Parameters:
  • energy_monitor – Type: EnergyMonitor *
Output Parameters:
  • ret_error_count_ack_checksum – Type: uint32_t, Range: [0 to 232 - 1]
  • ret_error_count_message_checksum – Type: uint32_t, Range: [0 to 232 - 1]
  • ret_error_count_frame – Type: uint32_t, Range: [0 to 232 - 1]
  • ret_error_count_overflow – Type: uint32_t, Range: [0 to 232 - 1]
Returns:
  • error_code – Type: int

Returns the error count for the communication between Brick and Bricklet.

The errors are divided into

  • ACK checksum errors,
  • message checksum errors,
  • framing errors and
  • overflow errors.

The errors counts are for errors that occur on the Bricklet side. All Bricks have a similar function that returns the errors on the Brick side.

int energy_monitor_set_bootloader_mode(EnergyMonitor *energy_monitor, uint8_t mode, uint8_t *ret_status)
Parameters:
  • energy_monitor – Type: EnergyMonitor *
  • mode – Type: uint8_t, Range: See constants
Output Parameters:
  • ret_status – Type: uint8_t, Range: See constants
Returns:
  • error_code – Type: int

Sets the bootloader mode and returns the status after the requested mode change was instigated.

You can change from bootloader mode to firmware mode and vice versa. A change from bootloader mode to firmware mode will only take place if the entry function, device identifier and CRC are present and correct.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

The following constants are available for this function:

For mode:

  • ENERGY_MONITOR_BOOTLOADER_MODE_BOOTLOADER = 0
  • ENERGY_MONITOR_BOOTLOADER_MODE_FIRMWARE = 1
  • ENERGY_MONITOR_BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • ENERGY_MONITOR_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • ENERGY_MONITOR_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4

For ret_status:

  • ENERGY_MONITOR_BOOTLOADER_STATUS_OK = 0
  • ENERGY_MONITOR_BOOTLOADER_STATUS_INVALID_MODE = 1
  • ENERGY_MONITOR_BOOTLOADER_STATUS_NO_CHANGE = 2
  • ENERGY_MONITOR_BOOTLOADER_STATUS_ENTRY_FUNCTION_NOT_PRESENT = 3
  • ENERGY_MONITOR_BOOTLOADER_STATUS_DEVICE_IDENTIFIER_INCORRECT = 4
  • ENERGY_MONITOR_BOOTLOADER_STATUS_CRC_MISMATCH = 5
int energy_monitor_get_bootloader_mode(EnergyMonitor *energy_monitor, uint8_t *ret_mode)
Parameters:
  • energy_monitor – Type: EnergyMonitor *
Output Parameters:
  • ret_mode – Type: uint8_t, Range: See constants
Returns:
  • error_code – Type: int

Returns the current bootloader mode, see energy_monitor_set_bootloader_mode().

The following constants are available for this function:

For ret_mode:

  • ENERGY_MONITOR_BOOTLOADER_MODE_BOOTLOADER = 0
  • ENERGY_MONITOR_BOOTLOADER_MODE_FIRMWARE = 1
  • ENERGY_MONITOR_BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • ENERGY_MONITOR_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • ENERGY_MONITOR_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
int energy_monitor_set_write_firmware_pointer(EnergyMonitor *energy_monitor, uint32_t pointer)
Parameters:
  • energy_monitor – Type: EnergyMonitor *
  • pointer – Type: uint32_t, Range: [0 to 232 - 1]
Returns:
  • error_code – Type: int

Sets the firmware pointer for energy_monitor_write_firmware(). The pointer has to be increased by chunks of size 64. The data is written to flash every 4 chunks (which equals to one page of size 256).

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

int energy_monitor_write_firmware(EnergyMonitor *energy_monitor, uint8_t data[64], uint8_t *ret_status)
Parameters:
  • energy_monitor – Type: EnergyMonitor *
  • data – Type: uint8_t[64], Range: [0 to 255]
Output Parameters:
  • ret_status – Type: uint8_t, Range: [0 to 255]
Returns:
  • error_code – Type: int

Writes 64 Bytes of firmware at the position as written by energy_monitor_set_write_firmware_pointer() before. The firmware is written to flash every 4 chunks.

You can only write firmware in bootloader mode.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

int energy_monitor_set_status_led_config(EnergyMonitor *energy_monitor, uint8_t config)
Parameters:
  • energy_monitor – Type: EnergyMonitor *
  • config – Type: uint8_t, Range: See constants
Returns:
  • error_code – Type: int

Sets the status LED configuration. By default the LED shows communication traffic between Brick and Bricklet, it flickers once for every 10 received data packets.

You can also turn the LED permanently on/off or show a heartbeat.

If the Bricklet is in bootloader mode, the LED is will show heartbeat by default.

The following constants are available for this function:

For config:

  • ENERGY_MONITOR_STATUS_LED_CONFIG_OFF = 0
  • ENERGY_MONITOR_STATUS_LED_CONFIG_ON = 1
  • ENERGY_MONITOR_STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • ENERGY_MONITOR_STATUS_LED_CONFIG_SHOW_STATUS = 3
int energy_monitor_get_status_led_config(EnergyMonitor *energy_monitor, uint8_t *ret_config)
Parameters:
  • energy_monitor – Type: EnergyMonitor *
Output Parameters:
  • ret_config – Type: uint8_t, Range: See constants
Returns:
  • error_code – Type: int

Returns the configuration as set by energy_monitor_set_status_led_config()

The following constants are available for this function:

For ret_config:

  • ENERGY_MONITOR_STATUS_LED_CONFIG_OFF = 0
  • ENERGY_MONITOR_STATUS_LED_CONFIG_ON = 1
  • ENERGY_MONITOR_STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • ENERGY_MONITOR_STATUS_LED_CONFIG_SHOW_STATUS = 3
int energy_monitor_get_chip_temperature(EnergyMonitor *energy_monitor, int16_t *ret_temperature)
Parameters:
  • energy_monitor – Type: EnergyMonitor *
Output Parameters:
  • ret_temperature – Type: int16_t, Range: [-215 to 215 - 1]
Returns:
  • error_code – Type: int

Returns the temperature in °C as measured inside the microcontroller. The value returned is not the ambient temperature!

The temperature is only proportional to the real temperature and it has bad accuracy. Practically it is only useful as an indicator for temperature changes.

int energy_monitor_reset(EnergyMonitor *energy_monitor)
Parameters:
  • energy_monitor – Type: EnergyMonitor *
Returns:
  • error_code – Type: int

Calling this function will reset the Bricklet. All configurations will be lost.

After a reset you have to create new device objects, calling functions on the existing ones will result in undefined behavior!

int energy_monitor_write_uid(EnergyMonitor *energy_monitor, uint32_t uid)
Parameters:
  • energy_monitor – Type: EnergyMonitor *
  • uid – Type: uint32_t, Range: [0 to 232 - 1]
Returns:
  • error_code – Type: int

Writes a new UID into flash. If you want to set a new UID you have to decode the Base58 encoded UID string into an integer first.

We recommend that you use Brick Viewer to change the UID.

int energy_monitor_read_uid(EnergyMonitor *energy_monitor, uint32_t *ret_uid)
Parameters:
  • energy_monitor – Type: EnergyMonitor *
Output Parameters:
  • ret_uid – Type: uint32_t, Range: [0 to 232 - 1]
Returns:
  • error_code – Type: int

Returns the current UID as an integer. Encode as Base58 to get the usual string version.

int energy_monitor_get_identity(EnergyMonitor *energy_monitor, char ret_uid[8], char ret_connected_uid[8], char *ret_position, uint8_t ret_hardware_version[3], uint8_t ret_firmware_version[3], uint16_t *ret_device_identifier)
Parameters:
  • energy_monitor – Type: EnergyMonitor *
Output Parameters:
  • ret_uid – Type: char[8]
  • ret_connected_uid – Type: char[8]
  • ret_position – Type: char
  • ret_hardware_version – Type: uint8_t[3], Range: [0 to 255]
  • ret_firmware_version – Type: uint8_t[3], Range: [0 to 255]
  • ret_device_identifier – Type: uint16_t, Range: [0 to 216 - 1]
Returns:
  • error_code – Type: int

Returns the UID, the UID where the Bricklet is connected to, the position, the hardware and firmware version as well as the device identifier.

The position can be 'a', 'b', 'c' or 'd'.

The device identifier numbers can be found here. There is also a constant for the device identifier of this Bricklet.

Callback Configuration Functions

void energy_monitor_register_callback(EnergyMonitor *energy_monitor, int16_t callback_id, void (*function)(void), void *user_data)
Parameters:
  • energy_monitor – Type: EnergyMonitor *
  • callback_id – Type: int16_t
  • function – Type: void (*)(void)
  • user_data – Type: void *

Registers the given function with the given callback_id. The user_data will be passed as the last parameter to the function.

The available callback IDs with corresponding function signatures are listed below.

int energy_monitor_set_energy_data_callback_configuration(EnergyMonitor *energy_monitor, uint32_t period, bool value_has_to_change)
Parameters:
  • energy_monitor – Type: EnergyMonitor *
  • period – Type: uint32_t, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
  • value_has_to_change – Type: bool, Default: false
Returns:
  • error_code – Type: int

The period is the period with which the ENERGY_MONITOR_CALLBACK_ENERGY_DATA callback is triggered periodically. A value of 0 turns the callback off.

If the value has to change-parameter is set to true, the callback is only triggered after the value has changed. If the value didn't change within the period, the callback is triggered immediately on change.

If it is set to false, the callback is continuously triggered with the period, independent of the value.

int energy_monitor_get_energy_data_callback_configuration(EnergyMonitor *energy_monitor, uint32_t *ret_period, bool *ret_value_has_to_change)
Parameters:
  • energy_monitor – Type: EnergyMonitor *
Output Parameters:
  • ret_period – Type: uint32_t, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
  • ret_value_has_to_change – Type: bool, Default: false
Returns:
  • error_code – Type: int

Returns the callback configuration as set by energy_monitor_set_energy_data_callback_configuration().

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done with the energy_monitor_register_callback() function:

void my_callback(int p, void *user_data) {
    printf("parameter: %d\n", p);
}

energy_monitor_register_callback(&energy_monitor, ENERGY_MONITOR_CALLBACK_EXAMPLE, (void (*)(void))my_callback, NULL);

The available constants with corresponding function signatures are described below.

Note

Using callbacks for recurring events is always preferred compared to using getters. It will use less USB bandwidth and the latency will be a lot better, since there is no round trip time.

ENERGY_MONITOR_CALLBACK_ENERGY_DATA
void callback(int32_t voltage, int32_t current, int32_t energy, int32_t real_power, int32_t apparent_power, int32_t reactive_power, uint16_t power_factor, uint16_t frequency, void *user_data)
Callback Parameters:
  • voltage – Type: int32_t, Range: [-231 to 231 - 1]
  • current – Type: int32_t, Range: [-231 to 231 - 1]
  • energy – Type: int32_t, Range: [-231 to 231 - 1]
  • real_power – Type: int32_t, Range: [-231 to 231 - 1]
  • apparent_power – Type: int32_t, Range: [-231 to 231 - 1]
  • reactive_power – Type: int32_t, Range: [-231 to 231 - 1]
  • power_factor – Type: uint16_t, Range: [0 to 216 - 1]
  • frequency – Type: uint16_t, Range: [0 to 216 - 1]
  • user_data – Type: void *

This callback is triggered periodically according to the configuration set by energy_monitor_set_energy_data_callback_configuration().

The parameters are the same as energy_monitor_get_energy_data().

Constants

ENERGY_MONITOR_DEVICE_IDENTIFIER

This constant is used to identify a Energy Monitor Bricklet.

The energy_monitor_get_identity() function and the IPCON_CALLBACK_ENUMERATE callback of the IP Connection have a device_identifier parameter to specify the Brick's or Bricklet's type.

ENERGY_MONITOR_DEVICE_DISPLAY_NAME

This constant represents the human readable name of a Energy Monitor Bricklet.