Class: Tinkerforge::BrickDC

Inherits:
Device
  • Object
show all
Defined in:
lib/tinkerforge/brick_dc.rb

Overview

Drives one brushed DC motor with up to 28V and 5A (peak)

Constant Summary collapse

DEVICE_IDENTIFIER =

:nodoc:

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DEVICE_DISPLAY_NAME =

:nodoc:

'DC Brick'
CALLBACK_UNDER_VOLTAGE =

This callback is triggered when the input voltage drops below the value set by BrickDC#set_minimum_voltage. The parameter is the current voltage given in mV.

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CALLBACK_EMERGENCY_SHUTDOWN =

This callback is triggered if either the current consumption is too high (above 5A) or the temperature of the driver chip is too high (above 175°C). These two possibilities are essentially the same, since the temperature will reach this threshold immediately if the motor consumes too much current. In case of a voltage below 3.3V (external or stack) this callback is triggered as well.

If this callback is triggered, the driver chip gets disabled at the same time. That means, BrickDC#enable has to be called to drive the motor again.

.. note

This callback only works in Drive/Brake mode (see BrickDC#set_drive_mode). In Drive/Coast mode it is unfortunately impossible to reliably read the overcurrent/overtemperature signal from the driver chip.

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CALLBACK_VELOCITY_REACHED =

This callback is triggered whenever a set velocity is reached. For example: If a velocity of 0 is present, acceleration is set to 5000 and velocity to 10000, CALLBACK_VELOCITY_REACHED will be triggered after about 2 seconds, when the set velocity is actually reached.

.. note

Since we can’t get any feedback from the DC motor, this only works if the acceleration (see BrickDC#set_acceleration) is set smaller or equal to the maximum acceleration of the motor. Otherwise the motor will lag behind the control value and the callback will be triggered too early.

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CALLBACK_CURRENT_VELOCITY =

This callback is triggered with the period that is set by BrickDC#set_current_velocity_period. The parameter is the current velocity used by the motor.

CALLBACK_CURRENT_VELOCITY is only triggered after the set period if there is a change in the velocity.

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FUNCTION_SET_VELOCITY =

:nodoc:

1
FUNCTION_GET_VELOCITY =

:nodoc:

2
FUNCTION_GET_CURRENT_VELOCITY =

:nodoc:

3
FUNCTION_SET_ACCELERATION =

:nodoc:

4
FUNCTION_GET_ACCELERATION =

:nodoc:

5
FUNCTION_SET_PWM_FREQUENCY =

:nodoc:

6
FUNCTION_GET_PWM_FREQUENCY =

:nodoc:

7
FUNCTION_FULL_BRAKE =

:nodoc:

8
FUNCTION_GET_STACK_INPUT_VOLTAGE =

:nodoc:

9
FUNCTION_GET_EXTERNAL_INPUT_VOLTAGE =

:nodoc:

10
FUNCTION_GET_CURRENT_CONSUMPTION =

:nodoc:

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FUNCTION_ENABLE =

:nodoc:

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FUNCTION_DISABLE =

:nodoc:

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FUNCTION_IS_ENABLED =

:nodoc:

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FUNCTION_SET_MINIMUM_VOLTAGE =

:nodoc:

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FUNCTION_GET_MINIMUM_VOLTAGE =

:nodoc:

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FUNCTION_SET_DRIVE_MODE =

:nodoc:

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FUNCTION_GET_DRIVE_MODE =

:nodoc:

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FUNCTION_SET_CURRENT_VELOCITY_PERIOD =

:nodoc:

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FUNCTION_GET_CURRENT_VELOCITY_PERIOD =

:nodoc:

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FUNCTION_ENABLE_STATUS_LED =

:nodoc:

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FUNCTION_DISABLE_STATUS_LED =

:nodoc:

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FUNCTION_IS_STATUS_LED_ENABLED =

:nodoc:

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FUNCTION_GET_PROTOCOL1_BRICKLET_NAME =

:nodoc:

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FUNCTION_GET_CHIP_TEMPERATURE =

:nodoc:

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FUNCTION_RESET =

:nodoc:

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FUNCTION_GET_IDENTITY =

:nodoc:

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DRIVE_MODE_DRIVE_BRAKE =

:nodoc:

0
DRIVE_MODE_DRIVE_COAST =

:nodoc:

1

Constants inherited from Device

Device::RESPONSE_EXPECTED_ALWAYS_FALSE, Device::RESPONSE_EXPECTED_ALWAYS_TRUE, Device::RESPONSE_EXPECTED_FALSE, Device::RESPONSE_EXPECTED_INVALID_FUNCTION_ID, Device::RESPONSE_EXPECTED_TRUE

Instance Attribute Summary

Attributes inherited from Device

#callback_formats, #expected_response_function_id, #expected_response_sequence_number, #registered_callbacks, #uid

Instance Method Summary collapse

Methods inherited from Device

#dequeue_response, #enqueue_response, #get_api_version, #get_response_expected, #send_request, #set_response_expected, #set_response_expected_all

Constructor Details

#initialize(uid, ipcon) ⇒ BrickDC

Creates an object with the unique device ID uid and adds it to the IP Connection ipcon.



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# File 'lib/tinkerforge/brick_dc.rb', line 92

def initialize(uid, ipcon)
  super uid, ipcon

  @api_version = [2, 0, 0]

  @response_expected[FUNCTION_SET_VELOCITY] = RESPONSE_EXPECTED_FALSE
  @response_expected[FUNCTION_GET_VELOCITY] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_GET_CURRENT_VELOCITY] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_SET_ACCELERATION] = RESPONSE_EXPECTED_FALSE
  @response_expected[FUNCTION_GET_ACCELERATION] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_SET_PWM_FREQUENCY] = RESPONSE_EXPECTED_FALSE
  @response_expected[FUNCTION_GET_PWM_FREQUENCY] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_FULL_BRAKE] = RESPONSE_EXPECTED_FALSE
  @response_expected[FUNCTION_GET_STACK_INPUT_VOLTAGE] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_GET_EXTERNAL_INPUT_VOLTAGE] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_GET_CURRENT_CONSUMPTION] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_ENABLE] = RESPONSE_EXPECTED_FALSE
  @response_expected[FUNCTION_DISABLE] = RESPONSE_EXPECTED_FALSE
  @response_expected[FUNCTION_IS_ENABLED] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_SET_MINIMUM_VOLTAGE] = RESPONSE_EXPECTED_TRUE
  @response_expected[FUNCTION_GET_MINIMUM_VOLTAGE] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_SET_DRIVE_MODE] = RESPONSE_EXPECTED_FALSE
  @response_expected[FUNCTION_GET_DRIVE_MODE] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_SET_CURRENT_VELOCITY_PERIOD] = RESPONSE_EXPECTED_TRUE
  @response_expected[FUNCTION_GET_CURRENT_VELOCITY_PERIOD] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[CALLBACK_UNDER_VOLTAGE] = RESPONSE_EXPECTED_ALWAYS_FALSE
  @response_expected[CALLBACK_EMERGENCY_SHUTDOWN] = RESPONSE_EXPECTED_ALWAYS_FALSE
  @response_expected[CALLBACK_VELOCITY_REACHED] = RESPONSE_EXPECTED_ALWAYS_FALSE
  @response_expected[CALLBACK_CURRENT_VELOCITY] = RESPONSE_EXPECTED_ALWAYS_FALSE
  @response_expected[FUNCTION_ENABLE_STATUS_LED] = RESPONSE_EXPECTED_FALSE
  @response_expected[FUNCTION_DISABLE_STATUS_LED] = RESPONSE_EXPECTED_FALSE
  @response_expected[FUNCTION_IS_STATUS_LED_ENABLED] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_GET_PROTOCOL1_BRICKLET_NAME] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_GET_CHIP_TEMPERATURE] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_RESET] = RESPONSE_EXPECTED_FALSE
  @response_expected[FUNCTION_GET_IDENTITY] = RESPONSE_EXPECTED_ALWAYS_TRUE

  @callback_formats[CALLBACK_UNDER_VOLTAGE] = 'S'
  @callback_formats[CALLBACK_EMERGENCY_SHUTDOWN] = ''
  @callback_formats[CALLBACK_VELOCITY_REACHED] = 's'
  @callback_formats[CALLBACK_CURRENT_VELOCITY] = 's'
end

Instance Method Details

#disable ⇒ Object

Disables the driver chip. The configurations are kept (velocity, acceleration, etc) but the motor is not driven until it is enabled again.



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# File 'lib/tinkerforge/brick_dc.rb', line 250

def disable
  send_request(FUNCTION_DISABLE, [], '', 0, '')
end

#disable_status_led ⇒ Object

Disables the status LED.

The status LED is the blue LED next to the USB connector. If enabled is is on and it flickers if data is transfered. If disabled it is always off.

The default state is enabled.

.. versionadded

2.3.1$nbsp;(Firmware)



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# File 'lib/tinkerforge/brick_dc.rb', line 334

def disable_status_led
  send_request(FUNCTION_DISABLE_STATUS_LED, [], '', 0, '')
end

#enable ⇒ Object

Enables the driver chip. The driver parameters can be configured (velocity, acceleration, etc) before it is enabled.



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# File 'lib/tinkerforge/brick_dc.rb', line 244

def enable
  send_request(FUNCTION_ENABLE, [], '', 0, '')
end

#enable_status_led ⇒ Object

Enables the status LED.

The status LED is the blue LED next to the USB connector. If enabled is is on and it flickers if data is transfered. If disabled it is always off.

The default state is enabled.

.. versionadded

2.3.1$nbsp;(Firmware)



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# File 'lib/tinkerforge/brick_dc.rb', line 322

def enable_status_led
  send_request(FUNCTION_ENABLE_STATUS_LED, [], '', 0, '')
end

#full_brake ⇒ Object

Executes an active full brake.

.. warning

This function is for emergency purposes, where an immediate brake is necessary. Depending on the current velocity and the strength of the motor, a full brake can be quite violent.

Call BrickDC#set_velocity with 0 if you just want to stop the motor.



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# File 'lib/tinkerforge/brick_dc.rb', line 210

def full_brake
  send_request(FUNCTION_FULL_BRAKE, [], '', 0, '')
end

#get_acceleration ⇒ Object

Returns the acceleration as set by BrickDC#set_acceleration.



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# File 'lib/tinkerforge/brick_dc.rb', line 179

def get_acceleration
  send_request(FUNCTION_GET_ACCELERATION, [], '', 2, 'S')
end

#get_chip_temperature ⇒ Object

Returns the temperature in °C/10 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 an accuracy of +-15%. Practically it is only useful as an indicator for temperature changes.



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# File 'lib/tinkerforge/brick_dc.rb', line 360

def get_chip_temperature
  send_request(FUNCTION_GET_CHIP_TEMPERATURE, [], '', 2, 's')
end

#get_current_consumption ⇒ Object

Returns the current consumption of the motor in mA.



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# File 'lib/tinkerforge/brick_dc.rb', line 238

def get_current_consumption
  send_request(FUNCTION_GET_CURRENT_CONSUMPTION, [], '', 2, 'S')
end

#get_current_velocity ⇒ Object

Returns the current velocity of the motor. This value is different from BrickDC#get_velocity whenever the motor is currently accelerating to a goal set by BrickDC#set_velocity.



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# File 'lib/tinkerforge/brick_dc.rb', line 158

def get_current_velocity
  send_request(FUNCTION_GET_CURRENT_VELOCITY, [], '', 2, 's')
end

#get_current_velocity_period ⇒ Object

Returns the period as set by BrickDC#set_current_velocity_period.



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# File 'lib/tinkerforge/brick_dc.rb', line 310

def get_current_velocity_period
  send_request(FUNCTION_GET_CURRENT_VELOCITY_PERIOD, [], '', 2, 'S')
end

#get_drive_mode ⇒ Object

Returns the drive mode, as set by BrickDC#set_drive_mode.



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# File 'lib/tinkerforge/brick_dc.rb', line 297

def get_drive_mode
  send_request(FUNCTION_GET_DRIVE_MODE, [], '', 1, 'C')
end

#get_external_input_voltage ⇒ Object

Returns the external input voltage in mV. The external input voltage is given via the black power input connector on the DC Brick.

If there is an external input voltage and a stack input voltage, the motor will be driven by the external input voltage. If there is only a stack voltage present, the motor will be driven by this voltage.

.. warning

This means, if you have a high stack voltage and a low external voltage, the motor will be driven with the low external voltage. If you then remove the external connection, it will immediately be driven by the high stack voltage.



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# File 'lib/tinkerforge/brick_dc.rb', line 233

def get_external_input_voltage
  send_request(FUNCTION_GET_EXTERNAL_INPUT_VOLTAGE, [], '', 2, 'S')
end

#get_identity ⇒ Object

Returns the UID, the UID where the Brick is connected to, the position, the hardware and firmware version as well as the device identifier.

The position can be ‘0’-‘8’ (stack position).

The device identifier numbers can be found :ref:‘here <device_identifier>`. |device_identifier_constant|



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# File 'lib/tinkerforge/brick_dc.rb', line 382

def get_identity
  send_request(FUNCTION_GET_IDENTITY, [], '', 25, 'Z8 Z8 k C3 C3 S')
end

#get_minimum_voltage ⇒ Object

Returns the minimum voltage as set by BrickDC#set_minimum_voltage



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# File 'lib/tinkerforge/brick_dc.rb', line 271

def get_minimum_voltage
  send_request(FUNCTION_GET_MINIMUM_VOLTAGE, [], '', 2, 'S')
end

#get_protocol1_bricklet_name(port) ⇒ Object

Returns the firmware and protocol version and the name of the Bricklet for a given port.

This functions sole purpose is to allow automatic flashing of v1.x.y Bricklet plugins.



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# File 'lib/tinkerforge/brick_dc.rb', line 350

def get_protocol1_bricklet_name(port)
  send_request(FUNCTION_GET_PROTOCOL1_BRICKLET_NAME, [port], 'k', 44, 'C C3 Z40')
end

#get_pwm_frequency ⇒ Object

Returns the PWM frequency (in Hz) as set by BrickDC#set_pwm_frequency.



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# File 'lib/tinkerforge/brick_dc.rb', line 198

def get_pwm_frequency
  send_request(FUNCTION_GET_PWM_FREQUENCY, [], '', 2, 'S')
end

#get_stack_input_voltage ⇒ Object

Returns the stack input voltage in mV. The stack input voltage is the voltage that is supplied via the stack, i.e. it is given by a Step-Down or Step-Up Power Supply.



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# File 'lib/tinkerforge/brick_dc.rb', line 217

def get_stack_input_voltage
  send_request(FUNCTION_GET_STACK_INPUT_VOLTAGE, [], '', 2, 'S')
end

#get_velocity ⇒ Object

Returns the velocity as set by BrickDC#set_velocity.



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# File 'lib/tinkerforge/brick_dc.rb', line 151

def get_velocity
  send_request(FUNCTION_GET_VELOCITY, [], '', 2, 's')
end

#is_enabled ⇒ Object

Returns true if the driver chip is enabled, false otherwise.



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# File 'lib/tinkerforge/brick_dc.rb', line 255

def is_enabled
  send_request(FUNCTION_IS_ENABLED, [], '', 1, '?')
end

#is_status_led_enabled ⇒ Object

Returns true if the status LED is enabled, false otherwise.

.. versionadded

2.3.1$nbsp;(Firmware)



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# File 'lib/tinkerforge/brick_dc.rb', line 341

def is_status_led_enabled
  send_request(FUNCTION_IS_STATUS_LED_ENABLED, [], '', 1, '?')
end

#register_callback(id, &block) ⇒ Object

Registers a callback with ID id to the block block.



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# File 'lib/tinkerforge/brick_dc.rb', line 387

def register_callback(id, &block)
  callback = block
  @registered_callbacks[id] = callback
end

#reset ⇒ Object

Calling this function will reset the Brick. Calling this function on a Brick inside of a stack will reset the whole stack.

After a reset you have to create new device objects, calling functions on the existing ones will result in undefined behavior!



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# File 'lib/tinkerforge/brick_dc.rb', line 370

def reset
  send_request(FUNCTION_RESET, [], '', 0, '')
end

#set_acceleration(acceleration) ⇒ Object

Sets the acceleration of the motor. It is given in velocity/s. An acceleration of 10000 means, that every second the velocity is increased by 10000 (or about 30% duty cycle).

For example: If the current velocity is 0 and you want to accelerate to a velocity of 16000 (about 50% duty cycle) in 10 seconds, you should set an acceleration of 1600.

If acceleration is set to 0, there is no speed ramping, i.e. a new velocity is immediately given to the motor.

The default acceleration is 10000.



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# File 'lib/tinkerforge/brick_dc.rb', line 174

def set_acceleration(acceleration)
  send_request(FUNCTION_SET_ACCELERATION, [acceleration], 'S', 0, '')
end

#set_current_velocity_period(period) ⇒ Object

Sets a period in ms with which the CALLBACK_CURRENT_VELOCITY callback is triggered. A period of 0 turns the callback off.

The default value is 0.



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# File 'lib/tinkerforge/brick_dc.rb', line 305

def set_current_velocity_period(period)
  send_request(FUNCTION_SET_CURRENT_VELOCITY_PERIOD, [period], 'S', 0, '')
end

#set_drive_mode(mode) ⇒ Object

Sets the drive mode. Possible modes are:

  • 0 = Drive/Brake

  • 1 = Drive/Coast

These modes are different kinds of motor controls.

In Drive/Brake mode, the motor is always either driving or braking. There is no freewheeling. Advantages are: A more linear correlation between PWM and velocity, more exact accelerations and the possibility to drive with slower velocities.

In Drive/Coast mode, the motor is always either driving or freewheeling. Advantages are: Less current consumption and less demands on the motor and driver chip.

The default value is 0 = Drive/Brake.



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# File 'lib/tinkerforge/brick_dc.rb', line 292

def set_drive_mode(mode)
  send_request(FUNCTION_SET_DRIVE_MODE, [mode], 'C', 0, '')
end

#set_minimum_voltage(voltage) ⇒ Object

Sets the minimum voltage in mV, below which the CALLBACK_UNDER_VOLTAGE callback is triggered. The minimum possible value that works with the DC Brick is 6V. You can use this function to detect the discharge of a battery that is used to drive the motor. If you have a fixed power supply, you likely do not need this functionality.

The default value is 6V.



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# File 'lib/tinkerforge/brick_dc.rb', line 266

def set_minimum_voltage(voltage)
  send_request(FUNCTION_SET_MINIMUM_VOLTAGE, [voltage], 'S', 0, '')
end

#set_pwm_frequency(frequency) ⇒ Object

Sets the frequency (in Hz) of the PWM with which the motor is driven. The possible range of the frequency is 1-20000Hz. Often a high frequency is less noisy and the motor runs smoother. However, with a low frequency there are less switches and therefore fewer switching losses. Also with most motors lower frequencies enable higher torque.

If you have no idea what all this means, just ignore this function and use the default frequency, it will very likely work fine.

The default frequency is 15 kHz.



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# File 'lib/tinkerforge/brick_dc.rb', line 193

def set_pwm_frequency(frequency)
  send_request(FUNCTION_SET_PWM_FREQUENCY, [frequency], 'S', 0, '')
end

#set_velocity(velocity) ⇒ Object

Sets the velocity of the motor. Whereas -32767 is full speed backward, 0 is stop and 32767 is full speed forward. Depending on the acceleration (see BrickDC#set_acceleration), the motor is not immediately brought to the velocity but smoothly accelerated.

The velocity describes the duty cycle of the PWM with which the motor is controlled, e.g. a velocity of 3277 sets a PWM with a 10% duty cycle. You can not only control the duty cycle of the PWM but also the frequency, see BrickDC#set_pwm_frequency.

The default velocity is 0.



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# File 'lib/tinkerforge/brick_dc.rb', line 146

def set_velocity(velocity)
  send_request(FUNCTION_SET_VELOCITY, [velocity], 's', 0, '')
end