Delphi/Lazarus - Voltage Bricklet

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

type
  TExample = class
  private
    ipcon: TIPConnection;
    v: TBrickletVoltage;
  public
    procedure Execute;
  end;

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

var
  e: TExample;

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

  { Create device object }
  v := TBrickletVoltage.Create(UID, ipcon);

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

  { Get current voltage }
  voltage := v.GetVoltage;
  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, BrickletVoltage;

type
  TExample = class
  private
    ipcon: TIPConnection;
    v: TBrickletVoltage;
  public
    procedure VoltageCB(sender: TBrickletVoltage; const voltage: word);
    procedure Execute;
  end;

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

var
  e: TExample;

{ Callback procedure for voltage callback }
procedure TExample.VoltageCB(sender: TBrickletVoltage; const voltage: word);
begin
  WriteLn(Format('Voltage: %f V', [voltage/1000.0]));
end;

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

  { Create device object }
  v := TBrickletVoltage.Create(UID, ipcon);

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

  { Register voltage callback to procedure VoltageCB }
  v.OnVoltage := {$ifdef FPC}@{$endif}VoltageCB;

  { Set period for voltage callback to 1s (1000ms)
    Note: The voltage callback is only called every second
          if the voltage has changed since the last call! }
  v.SetVoltageCallbackPeriod(1000);

  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, BrickletVoltage;

type
  TExample = class
  private
    ipcon: TIPConnection;
    v: TBrickletVoltage;
  public
    procedure VoltageReachedCB(sender: TBrickletVoltage; const voltage: word);
    procedure Execute;
  end;

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

var
  e: TExample;

{ Callback procedure for voltage reached callback }
procedure TExample.VoltageReachedCB(sender: TBrickletVoltage; const voltage: word);
begin
  WriteLn(Format('Voltage: %f V', [voltage/1000.0]));
end;

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

  { Create device object }
  v := TBrickletVoltage.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) }
  v.SetDebouncePeriod(10000);

  { Register voltage reached callback to procedure VoltageReachedCB }
  v.OnVoltageReached := {$ifdef FPC}@{$endif}VoltageReachedCB;

  { Configure threshold for voltage "greater than 5 V" }
  v.SetVoltageCallbackThreshold('>', 5*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 TBrickletVoltage.Create(const uid: string; ipcon: TIPConnection)
Parameters:
  • uid – Type: string
  • ipcon – Type: TIPConnection
Returns:
  • voltage – Type: TBrickletVoltage

Creates an object with the unique device ID uid:

voltage := TBrickletVoltage.Create('YOUR_DEVICE_UID', ipcon);

This object can then be used after the IP Connection is connected.

function TBrickletVoltage.GetVoltage: word
Returns:
  • voltage – Type: word, Unit: 1 mV, Range: [0 to 50000]

Returns the voltage of the sensor.

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

Advanced Functions

function TBrickletVoltage.GetAnalogValue: word
Returns:
  • value – Type: word, Range: [0 to 212 - 1]

Returns the value as read by a 12-bit analog-to-digital converter.

Note

The value returned by GetVoltage is averaged over several samples to yield less noise, while GetAnalogValue gives back raw unfiltered analog values. The only reason to use GetAnalogValue is, if you need the full resolution of the analog-to-digital converter.

If you want the analog value periodically, it is recommended to use the OnAnalogValue callback and set the period with SetAnalogValueCallbackPeriod.

procedure TBrickletVoltage.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)
Output Parameters:
  • uid – Type: string, Length: up to 8
  • connectedUid – Type: string, Length: up to 8
  • position – Type: char, Range: ['a' to 'h', 'z']
  • hardwareVersion – Type: array [0..2] of byte
    • 0: major – Type: byte, Range: [0 to 255]
    • 1: minor – Type: byte, Range: [0 to 255]
    • 2: revision – Type: byte, Range: [0 to 255]
  • firmwareVersion – Type: array [0..2] of byte
    • 0: major – Type: byte, Range: [0 to 255]
    • 1: minor – Type: byte, Range: [0 to 255]
    • 2: revision – Type: byte, Range: [0 to 255]
  • deviceIdentifier – Type: word, Range: [0 to 216 - 1]

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', 'd', 'e', 'f', 'g' or 'h' (Bricklet Port). A Bricklet connected to an Isolator Bricklet is always as position 'z'.

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

Callback Configuration Functions

procedure TBrickletVoltage.SetVoltageCallbackPeriod(const period: longword)
Parameters:
  • period – Type: longword, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

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

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

function TBrickletVoltage.GetVoltageCallbackPeriod: longword
Returns:
  • period – Type: longword, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Returns the period as set by SetVoltageCallbackPeriod.

procedure TBrickletVoltage.SetAnalogValueCallbackPeriod(const period: longword)
Parameters:
  • period – Type: longword, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

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

The OnAnalogValue callback is only triggered if the analog value has changed since the last triggering.

function TBrickletVoltage.GetAnalogValueCallbackPeriod: longword
Returns:
  • period – Type: longword, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Returns the period as set by SetAnalogValueCallbackPeriod.

procedure TBrickletVoltage.SetVoltageCallbackThreshold(const option: char; const min: word; const max: word)
Parameters:
  • option – Type: char, Range: See constants, Default: 'x'
  • min – Type: word, Unit: 1 mV, Range: [0 to 216 - 1], Default: 0
  • max – Type: word, Unit: 1 mV, Range: [0 to 216 - 1], Default: 0

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 following constants are available for this function:

For option:

  • BRICKLET_VOLTAGE_THRESHOLD_OPTION_OFF = 'x'
  • BRICKLET_VOLTAGE_THRESHOLD_OPTION_OUTSIDE = 'o'
  • BRICKLET_VOLTAGE_THRESHOLD_OPTION_INSIDE = 'i'
  • BRICKLET_VOLTAGE_THRESHOLD_OPTION_SMALLER = '<'
  • BRICKLET_VOLTAGE_THRESHOLD_OPTION_GREATER = '>'
procedure TBrickletVoltage.GetVoltageCallbackThreshold(out option: char; out min: word; out max: word)
Output Parameters:
  • option – Type: char, Range: See constants, Default: 'x'
  • min – Type: word, Unit: 1 mV, Range: [0 to 216 - 1], Default: 0
  • max – Type: word, Unit: 1 mV, Range: [0 to 216 - 1], Default: 0

Returns the threshold as set by SetVoltageCallbackThreshold.

The following constants are available for this function:

For option:

  • BRICKLET_VOLTAGE_THRESHOLD_OPTION_OFF = 'x'
  • BRICKLET_VOLTAGE_THRESHOLD_OPTION_OUTSIDE = 'o'
  • BRICKLET_VOLTAGE_THRESHOLD_OPTION_INSIDE = 'i'
  • BRICKLET_VOLTAGE_THRESHOLD_OPTION_SMALLER = '<'
  • BRICKLET_VOLTAGE_THRESHOLD_OPTION_GREATER = '>'
procedure TBrickletVoltage.SetAnalogValueCallbackThreshold(const option: char; const min: word; const max: word)
Parameters:
  • option – Type: char, Range: See constants, Default: 'x'
  • min – Type: word, Range: [0 to 216 - 1], Default: 0
  • max – Type: word, Range: [0 to 216 - 1], Default: 0

Sets the thresholds for the OnAnalogValueReached callback.

The following options are possible:

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

The following constants are available for this function:

For option:

  • BRICKLET_VOLTAGE_THRESHOLD_OPTION_OFF = 'x'
  • BRICKLET_VOLTAGE_THRESHOLD_OPTION_OUTSIDE = 'o'
  • BRICKLET_VOLTAGE_THRESHOLD_OPTION_INSIDE = 'i'
  • BRICKLET_VOLTAGE_THRESHOLD_OPTION_SMALLER = '<'
  • BRICKLET_VOLTAGE_THRESHOLD_OPTION_GREATER = '>'
procedure TBrickletVoltage.GetAnalogValueCallbackThreshold(out option: char; out min: word; out max: word)
Output Parameters:
  • option – Type: char, Range: See constants, Default: 'x'
  • min – Type: word, Range: [0 to 216 - 1], Default: 0
  • max – Type: word, Range: [0 to 216 - 1], Default: 0

Returns the threshold as set by SetAnalogValueCallbackThreshold.

The following constants are available for this function:

For option:

  • BRICKLET_VOLTAGE_THRESHOLD_OPTION_OFF = 'x'
  • BRICKLET_VOLTAGE_THRESHOLD_OPTION_OUTSIDE = 'o'
  • BRICKLET_VOLTAGE_THRESHOLD_OPTION_INSIDE = 'i'
  • BRICKLET_VOLTAGE_THRESHOLD_OPTION_SMALLER = '<'
  • BRICKLET_VOLTAGE_THRESHOLD_OPTION_GREATER = '>'
procedure TBrickletVoltage.SetDebouncePeriod(const debounce: longword)
Parameters:
  • debounce – Type: longword, Unit: 1 ms, Range: [0 to 232 - 1], Default: 100

Sets the period with which the threshold callbacks

are triggered, if the thresholds

keep being reached.

function TBrickletVoltage.GetDebouncePeriod: longword
Returns:
  • debounce – Type: longword, Unit: 1 ms, Range: [0 to 232 - 1], Default: 100

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: TBrickletVoltage; const value: longint);
begin
  WriteLn(Format('Value: %d', [value]));
end;

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

The available callback properties and their parameter types 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 TBrickletVoltage.OnVoltage
procedure(sender: TBrickletVoltage; const voltage: word) of object;
Callback Parameters:
  • sender – Type: TBrickletVoltage
  • voltage – Type: word, Unit: 1 mV, Range: [0 to 50000]

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

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

property TBrickletVoltage.OnAnalogValue
procedure(sender: TBrickletVoltage; const value: word) of object;
Callback Parameters:
  • sender – Type: TBrickletVoltage
  • value – Type: word, Range: [0 to 212 - 1]

This callback is triggered periodically with the period that is set by SetAnalogValueCallbackPeriod. The parameter is the analog value of the sensor.

The OnAnalogValue callback is only triggered if the voltage has changed since the last triggering.

property TBrickletVoltage.OnVoltageReached
procedure(sender: TBrickletVoltage; const voltage: word) of object;
Callback Parameters:
  • sender – Type: TBrickletVoltage
  • voltage – Type: word, Unit: 1 mV, Range: [0 to 50000]

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 TBrickletVoltage.OnAnalogValueReached
procedure(sender: TBrickletVoltage; const value: word) of object;
Callback Parameters:
  • sender – Type: TBrickletVoltage
  • value – Type: word, Range: [0 to 212 - 1]

This callback is triggered when the threshold as set by SetAnalogValueCallbackThreshold is reached. The parameter is the analog value of the sensor.

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

Virtual Functions

Virtual functions don't communicate with the device itself, but operate only on the API bindings device object. They can be called without the corresponding IP Connection object being connected.

function TBrickletVoltage.GetAPIVersion: array [0..2] of byte
Output Parameters:
  • apiVersion – Type: array [0..2] of byte
    • 0: major – Type: byte, Range: [0 to 255]
    • 1: minor – Type: byte, Range: [0 to 255]
    • 2: revision – Type: byte, Range: [0 to 255]

Returns the version of the API definition 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 TBrickletVoltage.GetResponseExpected(const functionId: byte): boolean
Parameters:
  • functionId – Type: byte, Range: See constants
Returns:
  • responseExpected – Type: 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 sent and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For functionId:

  • BRICKLET_VOLTAGE_FUNCTION_SET_VOLTAGE_CALLBACK_PERIOD = 3
  • BRICKLET_VOLTAGE_FUNCTION_SET_ANALOG_VALUE_CALLBACK_PERIOD = 5
  • BRICKLET_VOLTAGE_FUNCTION_SET_VOLTAGE_CALLBACK_THRESHOLD = 7
  • BRICKLET_VOLTAGE_FUNCTION_SET_ANALOG_VALUE_CALLBACK_THRESHOLD = 9
  • BRICKLET_VOLTAGE_FUNCTION_SET_DEBOUNCE_PERIOD = 11
procedure TBrickletVoltage.SetResponseExpected(const functionId: byte; const responseExpected: boolean)
Parameters:
  • functionId – Type: byte, Range: See constants
  • responseExpected – Type: 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 sent and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For functionId:

  • BRICKLET_VOLTAGE_FUNCTION_SET_VOLTAGE_CALLBACK_PERIOD = 3
  • BRICKLET_VOLTAGE_FUNCTION_SET_ANALOG_VALUE_CALLBACK_PERIOD = 5
  • BRICKLET_VOLTAGE_FUNCTION_SET_VOLTAGE_CALLBACK_THRESHOLD = 7
  • BRICKLET_VOLTAGE_FUNCTION_SET_ANALOG_VALUE_CALLBACK_THRESHOLD = 9
  • BRICKLET_VOLTAGE_FUNCTION_SET_DEBOUNCE_PERIOD = 11
procedure TBrickletVoltage.SetResponseExpectedAll(const responseExpected: boolean)
Parameters:
  • responseExpected – Type: boolean

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

Constants

const BRICKLET_VOLTAGE_DEVICE_IDENTIFIER

This constant is used to identify a Voltage Bricklet.

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

const BRICKLET_VOLTAGE_DEVICE_DISPLAY_NAME

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