Delphi/Lazarus - Voltage/Current Bricklet 2.0

This is the description of the Delphi/Lazarus API bindings for the Voltage/Current Bricklet 2.0. General information and technical specifications for the Voltage/Current Bricklet 2.0 are summarized in its hardware description.

An installation guide for the Delphi/Lazarus API bindings is part of their general description.

Examples

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

Simple

Download (ExampleSimple.pas)

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program ExampleSimple;

{$ifdef MSWINDOWS}{$apptype CONSOLE}{$endif}
{$ifdef FPC}{$mode OBJFPC}{$H+}{$endif}

uses
  SysUtils, IPConnection, BrickletVoltageCurrentV2;

type
  TExample = class
  private
    ipcon: TIPConnection;
    vc: TBrickletVoltageCurrentV2;
  public
    procedure Execute;
  end;

const
  HOST = 'localhost';
  PORT = 4223;
  UID = 'XYZ'; { Change XYZ to the UID of your Voltage/Current Bricklet 2.0 }

var
  e: TExample;

procedure TExample.Execute;
var voltage, current: longint;
begin
  { Create IP connection }
  ipcon := TIPConnection.Create;

  { Create device object }
  vc := TBrickletVoltageCurrentV2.Create(UID, ipcon);

  { Connect to brickd }
  ipcon.Connect(HOST, PORT);
  { Don't use device before ipcon is connected }

  { Get current voltage }
  voltage := vc.GetVoltage;
  WriteLn(Format('Voltage: %f V', [voltage/1000.0]));

  { Get current current }
  current := vc.GetCurrent;
  WriteLn(Format('Current: %f A', [current/1000.0]));

  WriteLn('Press key to exit');
  ReadLn;
  ipcon.Destroy; { Calls ipcon.Disconnect internally }
end;

begin
  e := TExample.Create;
  e.Execute;
  e.Destroy;
end.

Callback

Download (ExampleCallback.pas)

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program ExampleCallback;

{$ifdef MSWINDOWS}{$apptype CONSOLE}{$endif}
{$ifdef FPC}{$mode OBJFPC}{$H+}{$endif}

uses
  SysUtils, IPConnection, BrickletVoltageCurrentV2;

type
  TExample = class
  private
    ipcon: TIPConnection;
    vc: TBrickletVoltageCurrentV2;
  public
    procedure CurrentCB(sender: TBrickletVoltageCurrentV2; const current: longint);
    procedure Execute;
  end;

const
  HOST = 'localhost';
  PORT = 4223;
  UID = 'XYZ'; { Change XYZ to the UID of your Voltage/Current Bricklet 2.0 }

var
  e: TExample;

{ Callback procedure for current callback }
procedure TExample.CurrentCB(sender: TBrickletVoltageCurrentV2; const current: longint);
begin
  WriteLn(Format('Current: %f A', [current/1000.0]));
end;

procedure TExample.Execute;
begin
  { Create IP connection }
  ipcon := TIPConnection.Create;

  { Create device object }
  vc := TBrickletVoltageCurrentV2.Create(UID, ipcon);

  { Connect to brickd }
  ipcon.Connect(HOST, PORT);
  { Don't use device before ipcon is connected }

  { Register current callback to procedure CurrentCB }
  vc.OnCurrent := {$ifdef FPC}@{$endif}CurrentCB;

  { Set period for current callback to 1s (1000ms) without a threshold }
  vc.SetCurrentCallbackConfiguration(1000, false, 'x', 0, 0);

  WriteLn('Press key to exit');
  ReadLn;
  ipcon.Destroy; { Calls ipcon.Disconnect internally }
end;

begin
  e := TExample.Create;
  e.Execute;
  e.Destroy;
end.

Threshold

Download (ExampleThreshold.pas)

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program ExampleThreshold;

{$ifdef MSWINDOWS}{$apptype CONSOLE}{$endif}
{$ifdef FPC}{$mode OBJFPC}{$H+}{$endif}

uses
  SysUtils, IPConnection, BrickletVoltageCurrentV2;

type
  TExample = class
  private
    ipcon: TIPConnection;
    vc: TBrickletVoltageCurrentV2;
  public
    procedure PowerCB(sender: TBrickletVoltageCurrentV2; const power: longint);
    procedure Execute;
  end;

const
  HOST = 'localhost';
  PORT = 4223;
  UID = 'XYZ'; { Change XYZ to the UID of your Voltage/Current Bricklet 2.0 }

var
  e: TExample;

{ Callback procedure for power callback }
procedure TExample.PowerCB(sender: TBrickletVoltageCurrentV2; const power: longint);
begin
  WriteLn(Format('power: %f W', [power/1000.0]));
end;

procedure TExample.Execute;
begin
  { Create IP connection }
  ipcon := TIPConnection.Create;

  { Create device object }
  vc := TBrickletVoltageCurrentV2.Create(UID, ipcon);

  { Connect to brickd }
  ipcon.Connect(HOST, PORT);
  { Don't use device before ipcon is connected }

  { Register power callback to procedure PowerCB }
  vc.OnPower := {$ifdef FPC}@{$endif}PowerCB;

  { Configure threshold for power "greater than 10 W"
    with a debounce period of 1s (1000ms) }
  vc.SetPowerCallbackConfiguration(1000, false, '>', 10*1000, 0);

  WriteLn('Press key to exit');
  ReadLn;
  ipcon.Destroy; { Calls ipcon.Disconnect internally }
end;

begin
  e := TExample.Create;
  e.Execute;
  e.Destroy;
end.

API

Since Delphi does not support multiple return values directly, we use the out keyword to return multiple values from a function.

All functions and procedures listed below are thread-safe.

Basic Functions

constructor TBrickletVoltageCurrentV2.Create(const uid: string; ipcon: TIPConnection)

Creates an object with the unique device ID uid:

voltageCurrentV2 := TBrickletVoltageCurrentV2.Create('YOUR_DEVICE_UID', ipcon);

This object can then be used after the IP Connection is connected (see examples above).

function TBrickletVoltageCurrentV2.GetCurrent: longint

Returns the current. The value is in mA and between -20000mA and 20000mA.

If you want to get the value periodically, it is recommended to use the OnCurrent callback. You can set the callback configuration with SetCurrentCallbackConfiguration.

function TBrickletVoltageCurrentV2.GetVoltage: longint

Returns the voltage. The value is in mV and between 0mV and 36000mV.

If you want to get the value periodically, it is recommended to use the OnVoltage callback. You can set the callback configuration with SetVoltageCallbackConfiguration.

function TBrickletVoltageCurrentV2.GetPower: longint

Returns the power. The value is in mW and between 0mV and 720000mW.

If you want to get the value periodically, it is recommended to use the OnPower callback. You can set the callback configuration with SetPowerCallbackConfiguration.

procedure TBrickletVoltageCurrentV2.SetConfiguration(const averaging: byte; const voltageConversionTime: byte; const currentConversionTime: byte)

Sets the configuration of the Voltage/Current Bricklet 2.0. It is possible to configure number of averages as well as voltage and current conversion time.

Averaging:

Value Number of Averages
0 1
1 4
2 16
3 64
4 128
5 256
6 512
>=7 1024

Voltage/Current conversion:

Value Conversion time
0 140µs
1 204µs
2 332µs
3 588µs
4 1.1ms
5 2.116ms
6 4.156ms
>=7 8.244ms

The default values are 3, 4 and 4 (64, 1.1ms, 1.1ms) for averaging, voltage conversion and current conversion.

The following constants are available for this function:

  • BRICKLET_VOLTAGE_CURRENT_V2_AVERAGING_1 = 0
  • BRICKLET_VOLTAGE_CURRENT_V2_AVERAGING_4 = 1
  • BRICKLET_VOLTAGE_CURRENT_V2_AVERAGING_16 = 2
  • BRICKLET_VOLTAGE_CURRENT_V2_AVERAGING_64 = 3
  • BRICKLET_VOLTAGE_CURRENT_V2_AVERAGING_128 = 4
  • BRICKLET_VOLTAGE_CURRENT_V2_AVERAGING_256 = 5
  • BRICKLET_VOLTAGE_CURRENT_V2_AVERAGING_512 = 6
  • BRICKLET_VOLTAGE_CURRENT_V2_AVERAGING_1024 = 7
procedure TBrickletVoltageCurrentV2.GetConfiguration(out averaging: byte; out voltageConversionTime: byte; out currentConversionTime: byte)

Returns the configuration as set by SetConfiguration.

The following constants are available for this function:

  • BRICKLET_VOLTAGE_CURRENT_V2_AVERAGING_1 = 0
  • BRICKLET_VOLTAGE_CURRENT_V2_AVERAGING_4 = 1
  • BRICKLET_VOLTAGE_CURRENT_V2_AVERAGING_16 = 2
  • BRICKLET_VOLTAGE_CURRENT_V2_AVERAGING_64 = 3
  • BRICKLET_VOLTAGE_CURRENT_V2_AVERAGING_128 = 4
  • BRICKLET_VOLTAGE_CURRENT_V2_AVERAGING_256 = 5
  • BRICKLET_VOLTAGE_CURRENT_V2_AVERAGING_512 = 6
  • BRICKLET_VOLTAGE_CURRENT_V2_AVERAGING_1024 = 7

Advanced Functions

procedure TBrickletVoltageCurrentV2.SetCalibration(const voltageMultiplier: word; const voltageDivisor: word; const currentMultiplier: word; const currentDivisor: word)

Since the ADC and the shunt resistor used for the measurements are not perfect they need to be calibrated by a multiplier and a divisor if a very precise reading is needed.

For example, if you are expecting a current of 1000mA and you are measuring 1023mA, you can calibrate the Voltage/Current Bricklet by setting the current multiplier to 1000 and the divisor to 1023. The same applies for the voltage.

procedure TBrickletVoltageCurrentV2.GetCalibration(out voltageMultiplier: word; out voltageDivisor: word; out currentMultiplier: word; out currentDivisor: word)

Returns the calibration as set by SetCalibration.

function TBrickletVoltageCurrentV2.GetAPIVersion: array [0..2] of byte

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.

function TBrickletVoltageCurrentV2.GetResponseExpected(const functionId: byte): boolean

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 SetResponseExpected. 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.

See SetResponseExpected for the list of function ID constants available for this function.

procedure TBrickletVoltageCurrentV2.SetResponseExpected(const functionId: byte; const responseExpected: boolean)

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 function ID constants are available for this function:

  • BRICKLET_VOLTAGE_CURRENT_V2_FUNCTION_SET_CURRENT_CALLBACK_CONFIGURATION = 2
  • BRICKLET_VOLTAGE_CURRENT_V2_FUNCTION_SET_VOLTAGE_CALLBACK_CONFIGURATION = 6
  • BRICKLET_VOLTAGE_CURRENT_V2_FUNCTION_SET_POWER_CALLBACK_CONFIGURATION = 10
  • BRICKLET_VOLTAGE_CURRENT_V2_FUNCTION_SET_CONFIGURATION = 13
  • BRICKLET_VOLTAGE_CURRENT_V2_FUNCTION_SET_CALIBRATION = 15
  • BRICKLET_VOLTAGE_CURRENT_V2_FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
  • BRICKLET_VOLTAGE_CURRENT_V2_FUNCTION_SET_STATUS_LED_CONFIG = 239
  • BRICKLET_VOLTAGE_CURRENT_V2_FUNCTION_RESET = 243
  • BRICKLET_VOLTAGE_CURRENT_V2_FUNCTION_WRITE_UID = 248
procedure TBrickletVoltageCurrentV2.SetResponseExpectedAll(const responseExpected: boolean)

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

procedure TBrickletVoltageCurrentV2.GetSPITFPErrorCount(out errorCountAckChecksum: longword; out errorCountMessageChecksum: longword; out errorCountFrame: longword; out errorCountOverflow: longword)

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.

function TBrickletVoltageCurrentV2.SetBootloaderMode(const mode: byte): byte

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:

  • BRICKLET_VOLTAGE_CURRENT_V2_BOOTLOADER_MODE_BOOTLOADER = 0
  • BRICKLET_VOLTAGE_CURRENT_V2_BOOTLOADER_MODE_FIRMWARE = 1
  • BRICKLET_VOLTAGE_CURRENT_V2_BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BRICKLET_VOLTAGE_CURRENT_V2_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BRICKLET_VOLTAGE_CURRENT_V2_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
  • BRICKLET_VOLTAGE_CURRENT_V2_BOOTLOADER_STATUS_OK = 0
  • BRICKLET_VOLTAGE_CURRENT_V2_BOOTLOADER_STATUS_INVALID_MODE = 1
  • BRICKLET_VOLTAGE_CURRENT_V2_BOOTLOADER_STATUS_NO_CHANGE = 2
  • BRICKLET_VOLTAGE_CURRENT_V2_BOOTLOADER_STATUS_ENTRY_FUNCTION_NOT_PRESENT = 3
  • BRICKLET_VOLTAGE_CURRENT_V2_BOOTLOADER_STATUS_DEVICE_IDENTIFIER_INCORRECT = 4
  • BRICKLET_VOLTAGE_CURRENT_V2_BOOTLOADER_STATUS_CRC_MISMATCH = 5
function TBrickletVoltageCurrentV2.GetBootloaderMode: byte

Returns the current bootloader mode, see SetBootloaderMode.

The following constants are available for this function:

  • BRICKLET_VOLTAGE_CURRENT_V2_BOOTLOADER_MODE_BOOTLOADER = 0
  • BRICKLET_VOLTAGE_CURRENT_V2_BOOTLOADER_MODE_FIRMWARE = 1
  • BRICKLET_VOLTAGE_CURRENT_V2_BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BRICKLET_VOLTAGE_CURRENT_V2_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BRICKLET_VOLTAGE_CURRENT_V2_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
procedure TBrickletVoltageCurrentV2.SetWriteFirmwarePointer(const pointer: longword)

Sets the firmware pointer for WriteFirmware. 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.

function TBrickletVoltageCurrentV2.WriteFirmware(const data: array [0..63] of byte): byte

Writes 64 Bytes of firmware at the position as written by SetWriteFirmwarePointer 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.

procedure TBrickletVoltageCurrentV2.SetStatusLEDConfig(const config: byte)

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:

  • BRICKLET_VOLTAGE_CURRENT_V2_STATUS_LED_CONFIG_OFF = 0
  • BRICKLET_VOLTAGE_CURRENT_V2_STATUS_LED_CONFIG_ON = 1
  • BRICKLET_VOLTAGE_CURRENT_V2_STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BRICKLET_VOLTAGE_CURRENT_V2_STATUS_LED_CONFIG_SHOW_STATUS = 3
function TBrickletVoltageCurrentV2.GetStatusLEDConfig: byte

Returns the configuration as set by SetStatusLEDConfig

The following constants are available for this function:

  • BRICKLET_VOLTAGE_CURRENT_V2_STATUS_LED_CONFIG_OFF = 0
  • BRICKLET_VOLTAGE_CURRENT_V2_STATUS_LED_CONFIG_ON = 1
  • BRICKLET_VOLTAGE_CURRENT_V2_STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BRICKLET_VOLTAGE_CURRENT_V2_STATUS_LED_CONFIG_SHOW_STATUS = 3
function TBrickletVoltageCurrentV2.GetChipTemperature: smallint

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.

procedure TBrickletVoltageCurrentV2.Reset

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!

procedure TBrickletVoltageCurrentV2.WriteUID(const uid: longword)

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.

function TBrickletVoltageCurrentV2.ReadUID: longword

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

procedure TBrickletVoltageCurrentV2.GetIdentity(out uid: string; out connectedUid: string; out position: char; out hardwareVersion: array [0..2] of byte; out firmwareVersion: array [0..2] of byte; out deviceIdentifier: word)

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

procedure TBrickletVoltageCurrentV2.SetCurrentCallbackConfiguration(const period: longword; const valueHasToChange: boolean; const option: char; const min: longint; const max: longint)

The period in ms is the period with which the OnCurrent 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.

It is furthermore possible to constrain the callback with thresholds.

The option-parameter together with min/max sets a threshold for the OnCurrent callback.

The following options are possible:

Option Description
'x' Threshold is turned off
'o' Threshold is triggered when the value is outside the min and max values
'i' Threshold is triggered when the value is inside or equal to the min and max values
'<' Threshold is triggered when the value is smaller than the min value (max is ignored)
'>' Threshold is triggered when the value is greater than the min value (max is ignored)

If the option is set to 'x' (threshold turned off) the callback is triggered with the fixed period.

The default value is (0, false, 'x', 0, 0).

The following constants are available for this function:

  • BRICKLET_VOLTAGE_CURRENT_V2_THRESHOLD_OPTION_OFF = 'x'
  • BRICKLET_VOLTAGE_CURRENT_V2_THRESHOLD_OPTION_OUTSIDE = 'o'
  • BRICKLET_VOLTAGE_CURRENT_V2_THRESHOLD_OPTION_INSIDE = 'i'
  • BRICKLET_VOLTAGE_CURRENT_V2_THRESHOLD_OPTION_SMALLER = '<'
  • BRICKLET_VOLTAGE_CURRENT_V2_THRESHOLD_OPTION_GREATER = '>'
procedure TBrickletVoltageCurrentV2.GetCurrentCallbackConfiguration(out period: longword; out valueHasToChange: boolean; out option: char; out min: longint; out max: longint)

Returns the callback configuration as set by SetCurrentCallbackConfiguration.

The following constants are available for this function:

  • BRICKLET_VOLTAGE_CURRENT_V2_THRESHOLD_OPTION_OFF = 'x'
  • BRICKLET_VOLTAGE_CURRENT_V2_THRESHOLD_OPTION_OUTSIDE = 'o'
  • BRICKLET_VOLTAGE_CURRENT_V2_THRESHOLD_OPTION_INSIDE = 'i'
  • BRICKLET_VOLTAGE_CURRENT_V2_THRESHOLD_OPTION_SMALLER = '<'
  • BRICKLET_VOLTAGE_CURRENT_V2_THRESHOLD_OPTION_GREATER = '>'
procedure TBrickletVoltageCurrentV2.SetVoltageCallbackConfiguration(const period: longword; const valueHasToChange: boolean; const option: char; const min: longint; const max: longint)

The period in ms is the period with which the OnVoltage 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.

It is furthermore possible to constrain the callback with thresholds.

The option-parameter together with min/max sets a threshold for the OnVoltage callback.

The following options are possible:

Option Description
'x' Threshold is turned off
'o' Threshold is triggered when the value is outside the min and max values
'i' Threshold is triggered when the value is inside or equal to the min and max values
'<' Threshold is triggered when the value is smaller than the min value (max is ignored)
'>' Threshold is triggered when the value is greater than the min value (max is ignored)

If the option is set to 'x' (threshold turned off) the callback is triggered with the fixed period.

The default value is (0, false, 'x', 0, 0).

The following constants are available for this function:

  • BRICKLET_VOLTAGE_CURRENT_V2_THRESHOLD_OPTION_OFF = 'x'
  • BRICKLET_VOLTAGE_CURRENT_V2_THRESHOLD_OPTION_OUTSIDE = 'o'
  • BRICKLET_VOLTAGE_CURRENT_V2_THRESHOLD_OPTION_INSIDE = 'i'
  • BRICKLET_VOLTAGE_CURRENT_V2_THRESHOLD_OPTION_SMALLER = '<'
  • BRICKLET_VOLTAGE_CURRENT_V2_THRESHOLD_OPTION_GREATER = '>'
procedure TBrickletVoltageCurrentV2.GetVoltageCallbackConfiguration(out period: longword; out valueHasToChange: boolean; out option: char; out min: longint; out max: longint)

Returns the callback configuration as set by SetVoltageCallbackConfiguration.

The following constants are available for this function:

  • BRICKLET_VOLTAGE_CURRENT_V2_THRESHOLD_OPTION_OFF = 'x'
  • BRICKLET_VOLTAGE_CURRENT_V2_THRESHOLD_OPTION_OUTSIDE = 'o'
  • BRICKLET_VOLTAGE_CURRENT_V2_THRESHOLD_OPTION_INSIDE = 'i'
  • BRICKLET_VOLTAGE_CURRENT_V2_THRESHOLD_OPTION_SMALLER = '<'
  • BRICKLET_VOLTAGE_CURRENT_V2_THRESHOLD_OPTION_GREATER = '>'
procedure TBrickletVoltageCurrentV2.SetPowerCallbackConfiguration(const period: longword; const valueHasToChange: boolean; const option: char; const min: longint; const max: longint)

The period in ms is the period with which the OnPower 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.

It is furthermore possible to constrain the callback with thresholds.

The option-parameter together with min/max sets a threshold for the OnPower callback.

The following options are possible:

Option Description
'x' Threshold is turned off
'o' Threshold is triggered when the value is outside the min and max values
'i' Threshold is triggered when the value is inside or equal to the min and max values
'<' Threshold is triggered when the value is smaller than the min value (max is ignored)
'>' Threshold is triggered when the value is greater than the min value (max is ignored)

If the option is set to 'x' (threshold turned off) the callback is triggered with the fixed period.

The default value is (0, false, 'x', 0, 0).

The following constants are available for this function:

  • BRICKLET_VOLTAGE_CURRENT_V2_THRESHOLD_OPTION_OFF = 'x'
  • BRICKLET_VOLTAGE_CURRENT_V2_THRESHOLD_OPTION_OUTSIDE = 'o'
  • BRICKLET_VOLTAGE_CURRENT_V2_THRESHOLD_OPTION_INSIDE = 'i'
  • BRICKLET_VOLTAGE_CURRENT_V2_THRESHOLD_OPTION_SMALLER = '<'
  • BRICKLET_VOLTAGE_CURRENT_V2_THRESHOLD_OPTION_GREATER = '>'
procedure TBrickletVoltageCurrentV2.GetPowerCallbackConfiguration(out period: longword; out valueHasToChange: boolean; out option: char; out min: longint; out max: longint)

Returns the callback configuration as set by SetPowerCallbackConfiguration.

The following constants are available for this function:

  • BRICKLET_VOLTAGE_CURRENT_V2_THRESHOLD_OPTION_OFF = 'x'
  • BRICKLET_VOLTAGE_CURRENT_V2_THRESHOLD_OPTION_OUTSIDE = 'o'
  • BRICKLET_VOLTAGE_CURRENT_V2_THRESHOLD_OPTION_INSIDE = 'i'
  • BRICKLET_VOLTAGE_CURRENT_V2_THRESHOLD_OPTION_SMALLER = '<'
  • BRICKLET_VOLTAGE_CURRENT_V2_THRESHOLD_OPTION_GREATER = '>'

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done by assigning a procedure to an callback property of the device object:

procedure TExample.MyCallback(sender: TBrickletVoltageCurrentV2; const param: word);
begin
  WriteLn(param);
end;

voltageCurrentV2.OnExample := {$ifdef FPC}@{$endif}example.MyCallback;

The available callback property and their type of parameters 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.

property TBrickletVoltageCurrentV2.OnCurrent
procedure(sender: TBrickletVoltageCurrentV2; const current: longint) of object;

This callback is triggered periodically according to the configuration set by SetCurrentCallbackConfiguration.

The parameter is the same as GetCurrent.

property TBrickletVoltageCurrentV2.OnVoltage
procedure(sender: TBrickletVoltageCurrentV2; const voltage: longint) of object;

This callback is triggered periodically according to the configuration set by SetVoltageCallbackConfiguration.

The parameter is the same as GetVoltage.

property TBrickletVoltageCurrentV2.OnPower
procedure(sender: TBrickletVoltageCurrentV2; const power: longint) of object;

This callback is triggered periodically according to the configuration set by SetPowerCallbackConfiguration.

The parameter is the same as GetPower.

Constants

const BRICKLET_VOLTAGE_CURRENT_V2_DEVICE_IDENTIFIER

This constant is used to identify a Voltage/Current Bricklet 2.0.

The GetIdentity function and the OnEnumerate callback of the IP Connection have a deviceIdentifier parameter to specify the Brick's or Bricklet's type.

const BRICKLET_VOLTAGE_CURRENT_V2_DEVICE_DISPLAY_NAME

This constant represents the human readable name of a Voltage/Current Bricklet 2.0.