Delphi/Lazarus - Thermocouple Bricklet

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

type
  TExample = class
  private
    ipcon: TIPConnection;
    t: TBrickletThermocouple;
  public
    procedure Execute;
  end;

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

var
  e: TExample;

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

  { Create device object }
  t := TBrickletThermocouple.Create(UID, ipcon);

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

  { Get current temperature }
  temperature := t.GetTemperature;
  WriteLn(Format('Temperature: %f °C', [temperature/100.0]));

  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, BrickletThermocouple;

type
  TExample = class
  private
    ipcon: TIPConnection;
    t: TBrickletThermocouple;
  public
    procedure TemperatureCB(sender: TBrickletThermocouple; const temperature: longint);
    procedure Execute;
  end;

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

var
  e: TExample;

{ Callback procedure for temperature callback }
procedure TExample.TemperatureCB(sender: TBrickletThermocouple;
                                 const temperature: longint);
begin
  WriteLn(Format('Temperature: %f °C', [temperature/100.0]));
end;

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

  { Create device object }
  t := TBrickletThermocouple.Create(UID, ipcon);

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

  { Register temperature callback to procedure TemperatureCB }
  t.OnTemperature := {$ifdef FPC}@{$endif}TemperatureCB;

  { Set period for temperature callback to 1s (1000ms)
    Note: The temperature callback is only called every second
          if the temperature has changed since the last call! }
  t.SetTemperatureCallbackPeriod(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, BrickletThermocouple;

type
  TExample = class
  private
    ipcon: TIPConnection;
    t: TBrickletThermocouple;
  public
    procedure TemperatureReachedCB(sender: TBrickletThermocouple;
                                   const temperature: longint);
    procedure Execute;
  end;

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

var
  e: TExample;

{ Callback procedure for temperature reached callback }
procedure TExample.TemperatureReachedCB(sender: TBrickletThermocouple;
                                        const temperature: longint);
begin
  WriteLn(Format('Temperature: %f °C', [temperature/100.0]));
end;

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

  { Create device object }
  t := TBrickletThermocouple.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) }
  t.SetDebouncePeriod(10000);

  { Register temperature reached callback to procedure TemperatureReachedCB }
  t.OnTemperatureReached := {$ifdef FPC}@{$endif}TemperatureReachedCB;

  { Configure threshold for temperature "greater than 30 °C" }
  t.SetTemperatureCallbackThreshold('>', 30*100, 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 TBrickletThermocouple.Create(const uid: string; ipcon: TIPConnection)

Creates an object with the unique device ID uid:

thermocouple := TBrickletThermocouple.Create('YOUR_DEVICE_UID', ipcon);

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

function TBrickletThermocouple.GetTemperature: longint

Returns the temperature of the thermocouple. The value is given in °C/100, e.g. a value of 4223 means that a temperature of 42.23 °C is measured.

If you want to get the temperature periodically, it is recommended to use the OnTemperature callback and set the period with SetTemperatureCallbackPeriod.

Advanced Functions

procedure TBrickletThermocouple.SetConfiguration(const averaging: byte; const thermocoupleType: byte; const filter: byte)

You can configure averaging size, thermocouple type and frequency filtering.

Available averaging sizes are 1, 2, 4, 8 and 16 samples.

As thermocouple type you can use B, E, J, K, N, R, S and T. If you have a different thermocouple or a custom thermocouple you can also use G8 and G32. With these types the returned value will not be in °C/100, it will be calculated by the following formulas:

  • G8: value = 8 * 1.6 * 2^17 * Vin
  • G32: value = 32 * 1.6 * 2^17 * Vin

where Vin is the thermocouple input voltage.

The frequency filter can be either configured to 50Hz or to 60Hz. You should configure it according to your utility frequency.

The conversion time depends on the averaging and filter configuration, it can be calculated as follows:

  • 60Hz: time = 82 + (samples - 1) * 16.67
  • 50Hz: time = 98 + (samples - 1) * 20

The default configuration is 16 samples, K type and 50Hz.

The following constants are available for this function:

  • BRICKLET_THERMOCOUPLE_AVERAGING_1 = 1
  • BRICKLET_THERMOCOUPLE_AVERAGING_2 = 2
  • BRICKLET_THERMOCOUPLE_AVERAGING_4 = 4
  • BRICKLET_THERMOCOUPLE_AVERAGING_8 = 8
  • BRICKLET_THERMOCOUPLE_AVERAGING_16 = 16
  • BRICKLET_THERMOCOUPLE_TYPE_B = 0
  • BRICKLET_THERMOCOUPLE_TYPE_E = 1
  • BRICKLET_THERMOCOUPLE_TYPE_J = 2
  • BRICKLET_THERMOCOUPLE_TYPE_K = 3
  • BRICKLET_THERMOCOUPLE_TYPE_N = 4
  • BRICKLET_THERMOCOUPLE_TYPE_R = 5
  • BRICKLET_THERMOCOUPLE_TYPE_S = 6
  • BRICKLET_THERMOCOUPLE_TYPE_T = 7
  • BRICKLET_THERMOCOUPLE_TYPE_G8 = 8
  • BRICKLET_THERMOCOUPLE_TYPE_G32 = 9
  • BRICKLET_THERMOCOUPLE_FILTER_OPTION_50HZ = 0
  • BRICKLET_THERMOCOUPLE_FILTER_OPTION_60HZ = 1
procedure TBrickletThermocouple.GetConfiguration(out averaging: byte; out thermocoupleType: byte; out filter: byte)

Returns the configuration as set by SetConfiguration.

The following constants are available for this function:

  • BRICKLET_THERMOCOUPLE_AVERAGING_1 = 1
  • BRICKLET_THERMOCOUPLE_AVERAGING_2 = 2
  • BRICKLET_THERMOCOUPLE_AVERAGING_4 = 4
  • BRICKLET_THERMOCOUPLE_AVERAGING_8 = 8
  • BRICKLET_THERMOCOUPLE_AVERAGING_16 = 16
  • BRICKLET_THERMOCOUPLE_TYPE_B = 0
  • BRICKLET_THERMOCOUPLE_TYPE_E = 1
  • BRICKLET_THERMOCOUPLE_TYPE_J = 2
  • BRICKLET_THERMOCOUPLE_TYPE_K = 3
  • BRICKLET_THERMOCOUPLE_TYPE_N = 4
  • BRICKLET_THERMOCOUPLE_TYPE_R = 5
  • BRICKLET_THERMOCOUPLE_TYPE_S = 6
  • BRICKLET_THERMOCOUPLE_TYPE_T = 7
  • BRICKLET_THERMOCOUPLE_TYPE_G8 = 8
  • BRICKLET_THERMOCOUPLE_TYPE_G32 = 9
  • BRICKLET_THERMOCOUPLE_FILTER_OPTION_50HZ = 0
  • BRICKLET_THERMOCOUPLE_FILTER_OPTION_60HZ = 1
procedure TBrickletThermocouple.GetErrorState(out overUnder: boolean; out openCircuit: boolean)

Returns the current error state. There are two possible errors:

  • Over/Under Voltage and
  • Open Circuit.

Over/Under Voltage happens for voltages below 0V or above 3.3V. In this case it is very likely that your thermocouple is defective. An Open Circuit error indicates that there is no thermocouple connected.

You can use the OnErrorState callback to automatically get triggered when the error state changes.

function TBrickletThermocouple.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 TBrickletThermocouple.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.

The following constants are available for this function:

  • BRICKLET_THERMOCOUPLE_FUNCTION_SET_TEMPERATURE_CALLBACK_PERIOD = 2
  • BRICKLET_THERMOCOUPLE_FUNCTION_SET_TEMPERATURE_CALLBACK_THRESHOLD = 4
  • BRICKLET_THERMOCOUPLE_FUNCTION_SET_DEBOUNCE_PERIOD = 6
  • BRICKLET_THERMOCOUPLE_FUNCTION_SET_CONFIGURATION = 10
procedure TBrickletThermocouple.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 constants are available for this function:

  • BRICKLET_THERMOCOUPLE_FUNCTION_SET_TEMPERATURE_CALLBACK_PERIOD = 2
  • BRICKLET_THERMOCOUPLE_FUNCTION_SET_TEMPERATURE_CALLBACK_THRESHOLD = 4
  • BRICKLET_THERMOCOUPLE_FUNCTION_SET_DEBOUNCE_PERIOD = 6
  • BRICKLET_THERMOCOUPLE_FUNCTION_SET_CONFIGURATION = 10
procedure TBrickletThermocouple.SetResponseExpectedAll(const responseExpected: boolean)

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

procedure TBrickletThermocouple.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 TBrickletThermocouple.SetTemperatureCallbackPeriod(const period: longword)

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

The OnTemperature callback is only triggered if the temperature has changed since the last triggering.

The default value is 0.

function TBrickletThermocouple.GetTemperatureCallbackPeriod: longword

Returns the period as set by SetTemperatureCallbackPeriod.

procedure TBrickletThermocouple.SetTemperatureCallbackThreshold(const option: char; const min: longint; const max: longint)

Sets the thresholds for the OnTemperatureReached callback.

The following options are possible:

Option Description
'x' Callback is turned off
'o' Callback is triggered when the temperature is outside the min and max values
'i' Callback is triggered when the temperature is inside the min and max values
'<' Callback is triggered when the temperature is smaller than the min value (max is ignored)
'>' Callback is triggered when the temperature 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_THERMOCOUPLE_THRESHOLD_OPTION_OFF = 'x'
  • BRICKLET_THERMOCOUPLE_THRESHOLD_OPTION_OUTSIDE = 'o'
  • BRICKLET_THERMOCOUPLE_THRESHOLD_OPTION_INSIDE = 'i'
  • BRICKLET_THERMOCOUPLE_THRESHOLD_OPTION_SMALLER = '<'
  • BRICKLET_THERMOCOUPLE_THRESHOLD_OPTION_GREATER = '>'
procedure TBrickletThermocouple.GetTemperatureCallbackThreshold(out option: char; out min: longint; out max: longint)

Returns the threshold as set by SetTemperatureCallbackThreshold.

The following constants are available for this function:

  • BRICKLET_THERMOCOUPLE_THRESHOLD_OPTION_OFF = 'x'
  • BRICKLET_THERMOCOUPLE_THRESHOLD_OPTION_OUTSIDE = 'o'
  • BRICKLET_THERMOCOUPLE_THRESHOLD_OPTION_INSIDE = 'i'
  • BRICKLET_THERMOCOUPLE_THRESHOLD_OPTION_SMALLER = '<'
  • BRICKLET_THERMOCOUPLE_THRESHOLD_OPTION_GREATER = '>'
procedure TBrickletThermocouple.SetDebouncePeriod(const debounce: longword)

Sets the period in ms with which the threshold callback

is triggered, if the threshold

keeps being reached.

The default value is 100.

function TBrickletThermocouple.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: TBrickletThermocouple; const param: word);
begin
  WriteLn(param);
end;

thermocouple.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 TBrickletThermocouple.OnTemperature
procedure(sender: TBrickletThermocouple; const temperature: longint) of object;

This callback is triggered periodically with the period that is set by SetTemperatureCallbackPeriod. The parameter is the temperature of the thermocouple.

The OnTemperature callback is only triggered if the temperature has changed since the last triggering.

property TBrickletThermocouple.OnTemperatureReached
procedure(sender: TBrickletThermocouple; const temperature: longint) of object;

This callback is triggered when the threshold as set by SetTemperatureCallbackThreshold is reached. The parameter is the temperature of the thermocouple.

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

property TBrickletThermocouple.OnErrorState
procedure(sender: TBrickletThermocouple; const overUnder: boolean; const openCircuit: boolean) of object;

This Callback is triggered every time the error state changes (see GetErrorState).

Constants

const BRICKLET_THERMOCOUPLE_DEVICE_IDENTIFIER

This constant is used to identify a Thermocouple 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_THERMOCOUPLE_DEVICE_DISPLAY_NAME

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