Delphi/Lazarus - Voltage/Current Bricklet

This is the description of the Delphi/Lazarus API bindings for the Voltage/Current Bricklet. General information and technical specifications for the Voltage/Current Bricklet 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, BrickletVoltageCurrent;

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

const
  HOST = 'localhost';
  PORT = 4223;
  UID = 'ABC'; { Change to your UID }

var
  e: TExample;

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

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

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

  { Get current current and voltage (unit is mA and mV) }
  current := vc.GetCurrent;
  voltage := vc.GetVoltage;
  WriteLn(Format('Current: %f A', [current/1000.0]));
  WriteLn(Format('Voltage: %f V', [voltage/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, BrickletVoltageCurrent;

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

const
  HOST = 'localhost';
  PORT = 4223;
  UID = 'ABC'; { Change to your UID }

var
  e: TExample;

{ Callback function for current callback (parameter has unit mA) }
procedure TExample.CurrentCB(sender: TBrickletVoltageCurrent; 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 := TBrickletVoltageCurrent.Create(UID, ipcon);

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


  { Set Period for current callback to 1s (1000ms)
    Note: The current callback is only called every second if the
          current has changed since the last call! }
  vc.SetCurrentCallbackPeriod(1000);

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

  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, BrickletVoltageCurrent;

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

const
  HOST = 'localhost';
  PORT = 4223;
  UID = 'ABC'; { Change to your UID }

var
  e: TExample;

{ Callback for current greater than 1A }
procedure TExample.ReachedCB(sender: TBrickletVoltageCurrent; const current: longint);
begin
  WriteLn(Format('Current is greater than 1A: %f', [current/1000.0]));
end;

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

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

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


  { Get threshold callbacks with a debounce time of 10 seconds (10000ms) }
  vc.SetDebouncePeriod(10000);

  { Register threshold reached callback to procedure ReachedCB }
  vc.OnCurrentReached := {$ifdef FPC}@{$endif}ReachedCB;

  { Configure threshold for "greater than 1A" (unit is mA) }
  vc.SetCurrentCallbackThreshold('>', 1*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 TBrickletVoltageCurrent.Create(const uid: string; ipcon: TIPConnection)

Creates an object with the unique device ID uid:

voltageCurrent := TBrickletVoltageCurrent.Create('YOUR_DEVICE_UID', ipcon);

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

function TBrickletVoltageCurrent.GetCurrent: longint

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

If you want to get the current periodically, it is recommended to use the callback OnCurrent and set the period with SetCurrentCallbackPeriod.

function TBrickletVoltageCurrent.GetVoltage: longint

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

If you want to get the voltage periodically, it is recommended to use the callback OnVoltage and set the period with SetVoltageCallbackPeriod.

function TBrickletVoltageCurrent.GetPower: longint

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

If you want to get the power periodically, it is recommended to use the callback OnPower and set the period with SetPowerCallbackPeriod.

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

Sets the configuration of the Voltage/Current Bricklet. 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_AVERAGING_1 = 0
  • BRICKLET_VOLTAGE_CURRENT_AVERAGING_4 = 1
  • BRICKLET_VOLTAGE_CURRENT_AVERAGING_16 = 2
  • BRICKLET_VOLTAGE_CURRENT_AVERAGING_64 = 3
  • BRICKLET_VOLTAGE_CURRENT_AVERAGING_128 = 4
  • BRICKLET_VOLTAGE_CURRENT_AVERAGING_256 = 5
  • BRICKLET_VOLTAGE_CURRENT_AVERAGING_512 = 6
  • BRICKLET_VOLTAGE_CURRENT_AVERAGING_1024 = 7
procedure TBrickletVoltageCurrent.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_AVERAGING_1 = 0
  • BRICKLET_VOLTAGE_CURRENT_AVERAGING_4 = 1
  • BRICKLET_VOLTAGE_CURRENT_AVERAGING_16 = 2
  • BRICKLET_VOLTAGE_CURRENT_AVERAGING_64 = 3
  • BRICKLET_VOLTAGE_CURRENT_AVERAGING_128 = 4
  • BRICKLET_VOLTAGE_CURRENT_AVERAGING_256 = 5
  • BRICKLET_VOLTAGE_CURRENT_AVERAGING_512 = 6
  • BRICKLET_VOLTAGE_CURRENT_AVERAGING_1024 = 7

Advanced Functions

procedure TBrickletVoltageCurrent.SetCalibration(const gainMultiplier: word; const gainDivisor: word)

Since the shunt resistor that is used to measure the current is not perfectly precise, it needs to be calibrated by a multiplier and divisor if a very precise reading is needed.

For example, if you are expecting a measurement of 1000mA and you are measuring 1023mA, you can calibrate the Voltage/Current Bricklet by setting the multiplier to 1000 and the divisor to 1023.

procedure TBrickletVoltageCurrent.GetCalibration(out gainMultiplier: word; out gainDivisor: word)

Returns the calibration as set by SetCalibration.

function TBrickletVoltageCurrent.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 TBrickletVoltageCurrent.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 TBrickletVoltageCurrent.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 and callbacks it is always disabled.

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_FUNCTION_SET_CONFIGURATION = 4
  • BRICKLET_VOLTAGE_CURRENT_FUNCTION_SET_CALIBRATION = 6
  • BRICKLET_VOLTAGE_CURRENT_FUNCTION_SET_CURRENT_CALLBACK_PERIOD = 8
  • BRICKLET_VOLTAGE_CURRENT_FUNCTION_SET_VOLTAGE_CALLBACK_PERIOD = 10
  • BRICKLET_VOLTAGE_CURRENT_FUNCTION_SET_POWER_CALLBACK_PERIOD = 12
  • BRICKLET_VOLTAGE_CURRENT_FUNCTION_SET_CURRENT_CALLBACK_THRESHOLD = 14
  • BRICKLET_VOLTAGE_CURRENT_FUNCTION_SET_VOLTAGE_CALLBACK_THRESHOLD = 16
  • BRICKLET_VOLTAGE_CURRENT_FUNCTION_SET_POWER_CALLBACK_THRESHOLD = 18
  • BRICKLET_VOLTAGE_CURRENT_FUNCTION_SET_DEBOUNCE_PERIOD = 20
procedure TBrickletVoltageCurrent.SetResponseExpectedAll(const responseExpected: boolean)

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

procedure TBrickletVoltageCurrent.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 TBrickletVoltageCurrent.SetCurrentCallbackPeriod(const period: longword)

Sets the period in ms with which the OnCurrent callback is triggered periodically. A value of 0 turns the callback off.

OnCurrent is only triggered if the current has changed since the last triggering.

The default value is 0.

function TBrickletVoltageCurrent.GetCurrentCallbackPeriod: longword

Returns the period as set by SetCurrentCallbackPeriod.

procedure TBrickletVoltageCurrent.SetVoltageCallbackPeriod(const period: longword)

Sets the period in ms with which the OnVoltage callback is triggered periodically. A value of 0 turns the callback off.

OnVoltage is only triggered if the voltage has changed since the last triggering.

The default value is 0.

function TBrickletVoltageCurrent.GetVoltageCallbackPeriod: longword

Returns the period as set by SetVoltageCallbackPeriod.

procedure TBrickletVoltageCurrent.SetPowerCallbackPeriod(const period: longword)

Sets the period in ms with which the OnPower callback is triggered periodically. A value of 0 turns the callback off.

OnPower is only triggered if the power has changed since the last triggering.

The default value is 0.

function TBrickletVoltageCurrent.GetPowerCallbackPeriod: longword

Returns the period as set by GetPowerCallbackPeriod.

procedure TBrickletVoltageCurrent.SetCurrentCallbackThreshold(const option: char; const min: longint; const max: longint)

Sets the thresholds for the OnCurrentReached callback.

The following options are possible:

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

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

The following constants are available for this function:

  • BRICKLET_VOLTAGE_CURRENT_THRESHOLD_OPTION_OFF = 'x'
  • BRICKLET_VOLTAGE_CURRENT_THRESHOLD_OPTION_OUTSIDE = 'o'
  • BRICKLET_VOLTAGE_CURRENT_THRESHOLD_OPTION_INSIDE = 'i'
  • BRICKLET_VOLTAGE_CURRENT_THRESHOLD_OPTION_SMALLER = '<'
  • BRICKLET_VOLTAGE_CURRENT_THRESHOLD_OPTION_GREATER = '>'
procedure TBrickletVoltageCurrent.GetCurrentCallbackThreshold(out option: char; out min: longint; out max: longint)

Returns the threshold as set by SetCurrentCallbackThreshold.

The following constants are available for this function:

  • BRICKLET_VOLTAGE_CURRENT_THRESHOLD_OPTION_OFF = 'x'
  • BRICKLET_VOLTAGE_CURRENT_THRESHOLD_OPTION_OUTSIDE = 'o'
  • BRICKLET_VOLTAGE_CURRENT_THRESHOLD_OPTION_INSIDE = 'i'
  • BRICKLET_VOLTAGE_CURRENT_THRESHOLD_OPTION_SMALLER = '<'
  • BRICKLET_VOLTAGE_CURRENT_THRESHOLD_OPTION_GREATER = '>'
procedure TBrickletVoltageCurrent.SetVoltageCallbackThreshold(const option: char; const min: longint; const max: longint)

Sets the thresholds for the OnVoltageReached callback.

The following options are possible:

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

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

The following constants are available for this function:

  • BRICKLET_VOLTAGE_CURRENT_THRESHOLD_OPTION_OFF = 'x'
  • BRICKLET_VOLTAGE_CURRENT_THRESHOLD_OPTION_OUTSIDE = 'o'
  • BRICKLET_VOLTAGE_CURRENT_THRESHOLD_OPTION_INSIDE = 'i'
  • BRICKLET_VOLTAGE_CURRENT_THRESHOLD_OPTION_SMALLER = '<'
  • BRICKLET_VOLTAGE_CURRENT_THRESHOLD_OPTION_GREATER = '>'
procedure TBrickletVoltageCurrent.GetVoltageCallbackThreshold(out option: char; out min: longint; out max: longint)

Returns the threshold as set by SetVoltageCallbackThreshold.

The following constants are available for this function:

  • BRICKLET_VOLTAGE_CURRENT_THRESHOLD_OPTION_OFF = 'x'
  • BRICKLET_VOLTAGE_CURRENT_THRESHOLD_OPTION_OUTSIDE = 'o'
  • BRICKLET_VOLTAGE_CURRENT_THRESHOLD_OPTION_INSIDE = 'i'
  • BRICKLET_VOLTAGE_CURRENT_THRESHOLD_OPTION_SMALLER = '<'
  • BRICKLET_VOLTAGE_CURRENT_THRESHOLD_OPTION_GREATER = '>'
procedure TBrickletVoltageCurrent.SetPowerCallbackThreshold(const option: char; const min: longint; const max: longint)

Sets the thresholds for the OnPowerReached callback.

The following options are possible:

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

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

The following constants are available for this function:

  • BRICKLET_VOLTAGE_CURRENT_THRESHOLD_OPTION_OFF = 'x'
  • BRICKLET_VOLTAGE_CURRENT_THRESHOLD_OPTION_OUTSIDE = 'o'
  • BRICKLET_VOLTAGE_CURRENT_THRESHOLD_OPTION_INSIDE = 'i'
  • BRICKLET_VOLTAGE_CURRENT_THRESHOLD_OPTION_SMALLER = '<'
  • BRICKLET_VOLTAGE_CURRENT_THRESHOLD_OPTION_GREATER = '>'
procedure TBrickletVoltageCurrent.GetPowerCallbackThreshold(out option: char; out min: longint; out max: longint)

Returns the threshold as set by SetPowerCallbackThreshold.

The following constants are available for this function:

  • BRICKLET_VOLTAGE_CURRENT_THRESHOLD_OPTION_OFF = 'x'
  • BRICKLET_VOLTAGE_CURRENT_THRESHOLD_OPTION_OUTSIDE = 'o'
  • BRICKLET_VOLTAGE_CURRENT_THRESHOLD_OPTION_INSIDE = 'i'
  • BRICKLET_VOLTAGE_CURRENT_THRESHOLD_OPTION_SMALLER = '<'
  • BRICKLET_VOLTAGE_CURRENT_THRESHOLD_OPTION_GREATER = '>'
procedure TBrickletVoltageCurrent.SetDebouncePeriod(const debounce: longword)

Sets the period in ms with which the threshold callbacks

are triggered, if the thresholds

keep being reached.

The default value is 100.

function TBrickletVoltageCurrent.GetDebouncePeriod: longword

Returns the debounce period as set by SetDebouncePeriod.

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: TBrickletVoltageCurrent; const param: word);
begin
  WriteLn(param);
end;

voltageCurrent.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 TBrickletVoltageCurrent.OnCurrent
procedure(sender: TBrickletVoltageCurrent; const current: longint) of object;

This callback is triggered periodically with the period that is set by SetCurrentCallbackPeriod. The parameter is the current of the sensor.

OnCurrent is only triggered if the current has changed since the last triggering.

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

This callback is triggered periodically with the period that is set by SetVoltageCallbackPeriod. The parameter is the voltage of the sensor.

OnVoltage is only triggered if the voltage has changed since the last triggering.

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

This callback is triggered periodically with the period that is set by SetPowerCallbackPeriod. The parameter is the power of the sensor.

OnPower is only triggered if the power has changed since the last triggering.

property TBrickletVoltageCurrent.OnCurrentReached
procedure(sender: TBrickletVoltageCurrent; const current: longint) of object;

This callback is triggered when the threshold as set by SetCurrentCallbackThreshold is reached. The parameter is the current of the sensor.

If the threshold keeps being reached, the callback is triggered periodically with the period as set by SetDebouncePeriod.

property TBrickletVoltageCurrent.OnVoltageReached
procedure(sender: TBrickletVoltageCurrent; const voltage: longint) of object;

This callback is triggered when the threshold as set by SetVoltageCallbackThreshold is reached. The parameter is the voltage of the sensor.

If the threshold keeps being reached, the callback is triggered periodically with the period as set by SetDebouncePeriod.

property TBrickletVoltageCurrent.OnPowerReached
procedure(sender: TBrickletVoltageCurrent; const power: longint) of object;

This callback is triggered when the threshold as set by SetPowerCallbackThreshold is reached. The parameter is the power of the sensor.

If the threshold keeps being reached, the callback is triggered periodically with the period as set by SetDebouncePeriod.

Constants

const BRICKLET_VOLTAGE_CURRENT_DEVICE_IDENTIFIER

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

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

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