This is the description of the MATLAB/Octave 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 MATLAB/Octave API bindings is part of their general description.
The example code below is Public Domain (CC0 1.0).
Download (matlab_example_simple.m)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 | function matlab_example_callback()
import com.tinkerforge.IPConnection;
import com.tinkerforge.BrickletVoltageCurrent;
HOST = 'localhost';
PORT = 4223;
UID = '555'; % Change to your UID
ipcon = IPConnection(); % Create IP connection
vc = BrickletVoltageCurrent(UID, ipcon); % Create device object
ipcon.connect(HOST, PORT); % Connect to brickd
% Don't use device before ipcon is connected
% Get current current and voltage (unit is mA and mV)
current = vc.getCurrent();
voltage = vc.getVoltage();
fprintf('Current: %g A\n', current/1000.0);
fprintf('Voltage: %g V\n', voltage/1000.0);
input('Press any key to exit...\n', 's');
ipcon.disconnect();
end
|
Download (matlab_example_callback.m)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 | function matlab_example_callback()
import com.tinkerforge.IPConnection;
import com.tinkerforge.BrickletVoltageCurrent;
HOST = 'localhost';
PORT = 4223;
UID = '555'; % Change to your UID
ipcon = IPConnection(); % Create IP connection
vc = BrickletVoltageCurrent(UID, ipcon); % Create device object
ipcon.connect(HOST, PORT); % Connect to brickd
% Don't use device before ipcon is connected
% Set Period for current callback to 1s (1000ms)
% Note: The callback is only called every second if the
% current has changed since the last call!
vc.setCurrentCallbackPeriod(1000);
% Register current callback to function cb_current
set(vc, 'CurrentCallback', @(h, e) cb_current(e));
input('Press any key to exit...\n', 's');
ipcon.disconnect();
end
% Callback function for current callback (parameter has unit mA)
function cb_current(e)
fprintf('Current: %g A\n', e.current/1000.0);
end
|
Download (matlab_example_threshold.m)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 | function matlab_example_threshold()
import com.tinkerforge.IPConnection;
import com.tinkerforge.BrickletVoltageCurrent;
HOST = 'localhost';
PORT = 4223;
UID = '555'; % Change to your UID
ipcon = IPConnection(); % Create IP connection
vc = BrickletVoltageCurrent(UID, ipcon); % Create device object
ipcon.connect(HOST, PORT); % Connect to brickd
% 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 function cb_reached
set(vc, 'CurrentCallback', @(h, e) cb_reached(e));
% Configure threshold for "greater than 1A" (unit is mA)
vc.setCurrentCallbackThreshold('>', 1*1000, 0);
input('Press any key to exit...\n', 's');
ipcon.disconnect();
end
% Callback for current greater than 1A
function cb_reached(e)
fprintf('Current is greater than 1A: %g \n', e.current/1000.0);
end
|
Download (octave_example_simple.m)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 | function octave_example_simple()
more off;
HOST = "localhost";
PORT = 4223;
UID = "555"; % Change to your UID
ipcon = java_new("com.tinkerforge.IPConnection"); % Create IP connection
vc = java_new("com.tinkerforge.BrickletVoltageCurrent", UID, ipcon); % Create device object
ipcon.connect(HOST, PORT); % Connect to brickd
% Don't use device before ipcon is connected
% Get current current and voltage (unit is mA and mV)
current = vc.getCurrent();
voltage = vc.getVoltage();
fprintf("Current: %g A\n", current/1000.0);
fprintf("Voltage: %g V\n", voltage/1000.0);
input("Press any key to exit...\n", "s");
ipcon.disconnect();
end
|
Download (octave_example_callback.m)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 | function octave_example_callback()
more off;
HOST = "localhost";
PORT = 4223;
UID = "555"; % Change to your UID
ipcon = java_new("com.tinkerforge.IPConnection"); % Create IP connection
vc = java_new("com.tinkerforge.BrickletVoltageCurrent", UID, ipcon); % Create device object
ipcon.connect(HOST, PORT); % Connect to brickd
% Don't use device before ipcon is connected
% Set Period for current callback to 1s (1000ms)
% Note: The callback is only called every second if the
% current has changed since the last call!
vc.setCurrentCallbackPeriod(1000);
% Register humidity callback to function cb_humidity
vc.addCurrentCallback(@cb_current);
input("Press any key to exit...\n", "s");
ipcon.disconnect();
end
% Callback function for current callback (parameter has unit mA)
function cb_current(e)
fprintf("Current: %g A\n", e.current/1000.0);
end
|
Download (octave_example_threshold.m)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 | function octave_example_threshold()
more off;
HOST = "localhost";
PORT = 4223;
UID = "555"; % Change to your UID
ipcon = java_new("com.tinkerforge.IPConnection"); % Create IP connection
vc = java_new("com.tinkerforge.BrickletVoltageCurrent", UID, ipcon); % Create device object
ipcon.connect(HOST, PORT); % Connect to brickd
% 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 function cb_reached
vc.addCurrentReachedCallback(@cb_reached);
% Configure threshold for "greater than 1A" (unit is mA)
vc.setCurrentCallbackThreshold(vc.THRESHOLD_OPTION_GREATER, 1*1000, 0);
input("Press any key to exit...\n", "s");
ipcon.disconnect();
end
% Callback for current greater than 1A
function cb_reached(e)
fprintf("Current is greater than 1A: %g \n", e.current/1000);
end
|
Generally, every method of the MATLAB bindings that returns a value can throw a TimeoutException. This exception gets thrown if the device did not respond. If a cable based connection is used, it is unlikely that this exception gets thrown (assuming nobody unplugs the device). However, if a wireless connection is used, timeouts will occur if the distance to the device gets too big.
Beside the TimeoutException there is also a NotConnectedException that is thrown if a method needs to communicate with the device while the IP Connection is not connected.
Since the MATLAB bindings are based on Java and Java does not support multiple return values and return by reference is not possible for primitive types, we use small classes that only consist of member variables. The member variables of the returned objects are described in the corresponding method descriptions.
The package for all Brick/Bricklet bindings and the IP Connection is com.tinkerforge.*
All methods listed below are thread-safe.
Creates an object with the unique device ID uid.
In MATLAB:
import com.tinkerforge.BrickletVoltageCurrent;
voltageCurrent = BrickletVoltageCurrent('YOUR_DEVICE_UID', ipcon);
In Octave:
voltageCurrent = java_new("com.tinkerforge.BrickletVoltageCurrent", "YOUR_DEVICE_UID", ipcon);
This object can then be used after the IP Connection is connected (see examples above).
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 CurrentCallback and set the period with setCurrentCallbackPeriod().
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 VoltageCallback and set the period with setVoltageCallbackPeriod().
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 PowerCallback and set the period with setPowerCallbackPeriod().
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:
Returns the configuration as set by setConfiguration().
The following constants are available for this function:
The returned object has the public member variables short averaging, short voltageConversionTime and short currentConversionTime.
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.
Returns the calibration as set by setCalibration().
The returned object has the public member variables int gainMultiplier and int gainDivisor.
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.
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.
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:
Changes the response expected flag for all setter and callback configuration functions of this device at once.
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.
The returned object has the public member variables String uid, String connectedUid, char position, short[] hardwareVersion, short[] firmwareVersion and int deviceIdentifier.
Sets the period in ms with which the CurrentCallback callback is triggered periodically. A value of 0 turns the callback off.
CurrentCallback is only triggered if the current has changed since the last triggering.
The default value is 0.
Returns the period as set by setCurrentCallbackPeriod().
Sets the period in ms with which the VoltageCallback callback is triggered periodically. A value of 0 turns the callback off.
VoltageCallback is only triggered if the voltage has changed since the last triggering.
The default value is 0.
Returns the period as set by setVoltageCallbackPeriod().
Sets the period in ms with which the PowerCallback callback is triggered periodically. A value of 0 turns the callback off.
PowerCallback is only triggered if the power has changed since the last triggering.
The default value is 0.
Returns the period as set by getPowerCallbackPeriod().
Sets the thresholds for the CurrentReachedCallback 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:
Returns the threshold as set by setCurrentCallbackThreshold().
The following constants are available for this function:
The returned object has the public member variables char option, int min and int max.
Sets the thresholds for the VoltageReachedCallback 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:
Returns the threshold as set by setVoltageCallbackThreshold().
The following constants are available for this function:
The returned object has the public member variables char option, int min and int max.
Sets the thresholds for the PowerReachedCallback 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:
Returns the threshold as set by setPowerCallbackThreshold().
The following constants are available for this function:
The returned object has the public member variables char option, int min and int max.
Sets the period in ms with which the threshold callbacks
are triggered, if the thresholds
keep being reached.
The default value is 100.
Returns the debounce period as set by setDebouncePeriod().
Callbacks can be registered to receive time critical or recurring data from the device. The registration is done with "set" function of MATLAB. The parameters consist of the IP Connection object, the callback name and the callback function. For example, it looks like this in MATLAB:
function cb_example(e)
fprintf('Parameter: %s\n', e.param);
end
set(device, 'ExampleCallback', @(h, e) cb_example(e));
Due to a difference in the Octave Java support the "set" function cannot be used in Octave. The registration is done with "add*Callback" functions of the device object. It looks like this in Octave:
function cb_example(e)
fprintf("Parameter: %s\n", e.param);
end
device.addExampleCallback(@cb_example);
It is possible to add several callbacks and to remove them with the corresponding "remove*Callback" function.
The parameters of the callback are passed to the callback function as fields of the structure e, which is derived from the java.util.EventObject class. The available callback names with corresponding structure fields 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.
Parameters: | current -- int |
---|
This callback is triggered periodically with the period that is set by setCurrentCallbackPeriod(). The parameter is the current of the sensor.
CurrentCallback is only triggered if the current has changed since the last triggering.
In MATLAB the set() function can be used to register a callback function to this callback.
In Octave a callback function can be added to this callback using the addCurrentCallback() function. An added callback function can be removed with the removeCurrentCallback() function.
Parameters: | voltage -- int |
---|
This callback is triggered periodically with the period that is set by setVoltageCallbackPeriod(). The parameter is the voltage of the sensor.
VoltageCallback is only triggered if the voltage has changed since the last triggering.
In MATLAB the set() function can be used to register a callback function to this callback.
In Octave a callback function can be added to this callback using the addVoltageCallback() function. An added callback function can be removed with the removeVoltageCallback() function.
Parameters: | power -- int |
---|
This callback is triggered periodically with the period that is set by setPowerCallbackPeriod(). The parameter is the power of the sensor.
PowerCallback is only triggered if the power has changed since the last triggering.
In MATLAB the set() function can be used to register a callback function to this callback.
In Octave a callback function can be added to this callback using the addPowerCallback() function. An added callback function can be removed with the removePowerCallback() function.
Parameters: | current -- int |
---|
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().
In MATLAB the set() function can be used to register a callback function to this callback.
In Octave a callback function can be added to this callback using the addCurrentReachedCallback() function. An added callback function can be removed with the removeCurrentReachedCallback() function.
Parameters: | voltage -- int |
---|
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().
In MATLAB the set() function can be used to register a callback function to this callback.
In Octave a callback function can be added to this callback using the addVoltageReachedCallback() function. An added callback function can be removed with the removeVoltageReachedCallback() function.
Parameters: | power -- int |
---|
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().
In MATLAB the set() function can be used to register a callback function to this callback.
In Octave a callback function can be added to this callback using the addPowerReachedCallback() function. An added callback function can be removed with the removePowerReachedCallback() function.
This constant is used to identify a Voltage/Current Bricklet.
The getIdentity() function and the EnumerateCallback callback of the IP Connection have a deviceIdentifier parameter to specify the Brick's or Bricklet's type.