class Tinkerforge::BrickDC
Drives one brushed DC motor with up to 28V and 5A (peak)
Constants
- 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.The
CALLBACK_CURRENT_VELOCITY
callback is only triggered after the set period if there is a change in the velocity.- 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.
- 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.- 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, the
CALLBACK_VELOCITY_REACHED
callback 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.
Public Class Methods
Creates an object with the unique device ID uid
and adds it to the IP Connection ipcon
.
# File lib/tinkerforge/brick_dc.rb, line 108 def initialize(uid, ipcon) super uid, ipcon, DEVICE_IDENTIFIER, DEVICE_DISPLAY_NAME @api_version = [2, 0, 3] @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[FUNCTION_SET_SPITFP_BAUDRATE_CONFIG] = RESPONSE_EXPECTED_FALSE @response_expected[FUNCTION_GET_SPITFP_BAUDRATE_CONFIG] = RESPONSE_EXPECTED_ALWAYS_TRUE @response_expected[FUNCTION_GET_SEND_TIMEOUT_COUNT] = RESPONSE_EXPECTED_ALWAYS_TRUE @response_expected[FUNCTION_SET_SPITFP_BAUDRATE] = RESPONSE_EXPECTED_FALSE @response_expected[FUNCTION_GET_SPITFP_BAUDRATE] = RESPONSE_EXPECTED_ALWAYS_TRUE @response_expected[FUNCTION_GET_SPITFP_ERROR_COUNT] = RESPONSE_EXPECTED_ALWAYS_TRUE @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_WRITE_BRICKLET_PLUGIN] = RESPONSE_EXPECTED_FALSE @response_expected[FUNCTION_READ_BRICKLET_PLUGIN] = RESPONSE_EXPECTED_ALWAYS_TRUE @response_expected[FUNCTION_GET_IDENTITY] = RESPONSE_EXPECTED_ALWAYS_TRUE @callback_formats[CALLBACK_UNDER_VOLTAGE] = [10, 'S'] @callback_formats[CALLBACK_EMERGENCY_SHUTDOWN] = [8, ''] @callback_formats[CALLBACK_VELOCITY_REACHED] = [10, 's'] @callback_formats[CALLBACK_CURRENT_VELOCITY] = [10, 's'] @ipcon.add_device self end
Public Instance Methods
Disables the driver chip. The configurations are kept (velocity, acceleration, etc) but the motor is not driven until it is enabled again.
- .. warning
-
Disabling the driver chip while the motor is still turning can damage the driver chip. The motor should be stopped calling
BrickDC#set_velocity
with 0 before disabling the motor power. TheBrickDC#set_velocity
function will not wait until the motor is actually stopped. You have to explicitly wait for the appropriate time after calling theBrickDC#set_velocity
function before calling theBrickDC#disable
function.
# File lib/tinkerforge/brick_dc.rb, line 298 def disable check_validity send_request FUNCTION_DISABLE, [], '', 8, '' end
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$nbsp;(Firmware)
# File lib/tinkerforge/brick_dc.rb, line 492 def disable_status_led check_validity send_request FUNCTION_DISABLE_STATUS_LED, [], '', 8, '' end
Enables the driver chip. The driver parameters can be configured (velocity, acceleration, etc) before it is enabled.
# File lib/tinkerforge/brick_dc.rb, line 282 def enable check_validity send_request FUNCTION_ENABLE, [], '', 8, '' end
Enables the status LED.
The status LED is the blue LED next to the USB connector. If enabled is is on and it flickers if data is transfered. If disabled it is always off.
The default state is enabled.
- .. versionadded
-
2.3.1$nbsp;(Firmware)
# File lib/tinkerforge/brick_dc.rb, line 478 def enable_status_led check_validity send_request FUNCTION_ENABLE_STATUS_LED, [], '', 8, '' end
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.
# File lib/tinkerforge/brick_dc.rb, line 240 def full_brake check_validity send_request FUNCTION_FULL_BRAKE, [], '', 8, '' end
Returns the acceleration as set by BrickDC#set_acceleration
.
# File lib/tinkerforge/brick_dc.rb, line 205 def get_acceleration check_validity send_request FUNCTION_GET_ACCELERATION, [], '', 10, 'S' end
Returns the temperature 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.
# File lib/tinkerforge/brick_dc.rb, line 524 def get_chip_temperature check_validity send_request FUNCTION_GET_CHIP_TEMPERATURE, [], '', 10, 's' end
Returns the current consumption of the motor.
# File lib/tinkerforge/brick_dc.rb, line 274 def get_current_consumption check_validity send_request FUNCTION_GET_CURRENT_CONSUMPTION, [], '', 10, 'S' end
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
.
# File lib/tinkerforge/brick_dc.rb, line 182 def get_current_velocity check_validity send_request FUNCTION_GET_CURRENT_VELOCITY, [], '', 10, 's' end
Returns the period as set by BrickDC#set_current_velocity_period
.
# File lib/tinkerforge/brick_dc.rb, line 366 def get_current_velocity_period check_validity send_request FUNCTION_GET_CURRENT_VELOCITY_PERIOD, [], '', 10, 'S' end
Returns the drive mode, as set by BrickDC#set_drive_mode
.
# File lib/tinkerforge/brick_dc.rb, line 351 def get_drive_mode check_validity send_request FUNCTION_GET_DRIVE_MODE, [], '', 9, 'C' end
Returns the external input voltage. 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.
# File lib/tinkerforge/brick_dc.rb, line 267 def get_external_input_voltage check_validity send_request FUNCTION_GET_EXTERNAL_INPUT_VOLTAGE, [], '', 10, 'S' end
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 is the position in the stack from '0' (bottom) to '8' (top).
The device identifier numbers can be found :ref:`here <device_identifier>`. |device_identifier_constant|
# File lib/tinkerforge/brick_dc.rb, line 572 def get_identity send_request FUNCTION_GET_IDENTITY, [], '', 33, 'Z8 Z8 k C3 C3 S' end
Returns the minimum voltage as set by BrickDC#set_minimum_voltage
# File lib/tinkerforge/brick_dc.rb, line 323 def get_minimum_voltage check_validity send_request FUNCTION_GET_MINIMUM_VOLTAGE, [], '', 10, 'S' end
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.
# File lib/tinkerforge/brick_dc.rb, line 512 def get_protocol1_bricklet_name(port) check_validity send_request FUNCTION_GET_PROTOCOL1_BRICKLET_NAME, [port], 'k', 52, 'C C3 Z40' end
Returns the PWM frequency as set by BrickDC#set_pwm_frequency
.
# File lib/tinkerforge/brick_dc.rb, line 226 def get_pwm_frequency check_validity send_request FUNCTION_GET_PWM_FREQUENCY, [], '', 10, 'S' end
Returns the timeout count for the different communication methods.
The methods 0-2 are available for all Bricks, 3-7 only for Master Bricks.
This function is mostly used for debugging during development, in normal operation the counters should nearly always stay at 0.
- .. versionadded
-
2.3.3$nbsp;(Firmware)
# File lib/tinkerforge/brick_dc.rb, line 415 def get_send_timeout_count(communication_method) check_validity send_request FUNCTION_GET_SEND_TIMEOUT_COUNT, [communication_method], 'C', 12, 'L' end
Returns the baudrate for a given Bricklet port, see BrickDC#set_spitfp_baudrate
.
- .. versionadded
-
2.3.3$nbsp;(Firmware)
# File lib/tinkerforge/brick_dc.rb, line 445 def get_spitfp_baudrate(bricklet_port) check_validity send_request FUNCTION_GET_SPITFP_BAUDRATE, [bricklet_port], 'k', 12, 'L' end
Returns the baudrate config, see BrickDC#set_spitfp_baudrate_config
.
- .. versionadded
-
2.3.5$nbsp;(Firmware)
# File lib/tinkerforge/brick_dc.rb, line 401 def get_spitfp_baudrate_config check_validity send_request FUNCTION_GET_SPITFP_BAUDRATE_CONFIG, [], '', 13, '? L' end
Returns the error count for the communication between Brick and Bricklet.
The errors are divided into
-
ACK checksum errors,
-
message checksum errors,
-
framing errors and
-
overflow errors.
The errors counts are for errors that occur on the Brick side. All Bricklets have a similar function that returns the errors on the Bricklet side.
- .. versionadded
-
2.3.3$nbsp;(Firmware)
# File lib/tinkerforge/brick_dc.rb, line 464 def get_spitfp_error_count(bricklet_port) check_validity send_request FUNCTION_GET_SPITFP_ERROR_COUNT, [bricklet_port], 'k', 24, 'L L L L' end
Returns the stack input voltage. 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.
# File lib/tinkerforge/brick_dc.rb, line 249 def get_stack_input_voltage check_validity send_request FUNCTION_GET_STACK_INPUT_VOLTAGE, [], '', 10, 'S' end
Returns the velocity as set by BrickDC#set_velocity
.
# File lib/tinkerforge/brick_dc.rb, line 173 def get_velocity check_validity send_request FUNCTION_GET_VELOCITY, [], '', 10, 's' end
Returns true if the driver chip is enabled, false otherwise.
# File lib/tinkerforge/brick_dc.rb, line 305 def is_enabled check_validity send_request FUNCTION_IS_ENABLED, [], '', 9, '?' end
Returns true if the status LED is enabled, false otherwise.
- .. versionadded
-
2.3.1$nbsp;(Firmware)
# File lib/tinkerforge/brick_dc.rb, line 501 def is_status_led_enabled check_validity send_request FUNCTION_IS_STATUS_LED_ENABLED, [], '', 9, '?' end
Reads 32 bytes of firmware from the bricklet attached at the given port. The bytes are read starting at the position offset * 32.
This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.
# File lib/tinkerforge/brick_dc.rb, line 558 def read_bricklet_plugin(port, offset) check_validity send_request FUNCTION_READ_BRICKLET_PLUGIN, [port, offset], 'k C', 40, 'C32' end
Registers a callback with ID id
to the block block
.
# File lib/tinkerforge/brick_dc.rb, line 577 def register_callback(id, &block) callback = block @registered_callbacks[id] = callback end
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!
# File lib/tinkerforge/brick_dc.rb, line 536 def reset check_validity send_request FUNCTION_RESET, [], '', 8, '' end
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.
# File lib/tinkerforge/brick_dc.rb, line 198 def set_acceleration(acceleration) check_validity send_request FUNCTION_SET_ACCELERATION, [acceleration], 'S', 8, '' end
Sets a period with which the CALLBACK_CURRENT_VELOCITY
callback is triggered. A period of 0 turns the callback off.
# File lib/tinkerforge/brick_dc.rb, line 359 def set_current_velocity_period(period) check_validity send_request FUNCTION_SET_CURRENT_VELOCITY_PERIOD, [period], 'S', 8, '' end
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.
# File lib/tinkerforge/brick_dc.rb, line 344 def set_drive_mode(mode) check_validity send_request FUNCTION_SET_DRIVE_MODE, [mode], 'C', 8, '' end
Sets the minimum voltage, 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.
# File lib/tinkerforge/brick_dc.rb, line 316 def set_minimum_voltage(voltage) check_validity send_request FUNCTION_SET_MINIMUM_VOLTAGE, [voltage], 'S', 8, '' end
Sets the frequency of the PWM with which the motor is driven. 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.
# File lib/tinkerforge/brick_dc.rb, line 219 def set_pwm_frequency(frequency) check_validity send_request FUNCTION_SET_PWM_FREQUENCY, [frequency], 'S', 8, '' end
Sets the baudrate for a specific Bricklet port.
If you want to increase the throughput of Bricklets you can increase the baudrate. If you get a high error count because of high interference (see BrickDC#get_spitfp_error_count
) you can decrease the baudrate.
If the dynamic baudrate feature is enabled, the baudrate set by this function corresponds to the maximum baudrate (see BrickDC#set_spitfp_baudrate_config
).
Regulatory testing is done with the default baudrate. If CE compatibility or similar is necessary in your applications we recommend to not change the baudrate.
- .. versionadded
-
2.3.3$nbsp;(Firmware)
# File lib/tinkerforge/brick_dc.rb, line 436 def set_spitfp_baudrate(bricklet_port, baudrate) check_validity send_request FUNCTION_SET_SPITFP_BAUDRATE, [bricklet_port, baudrate], 'k L', 8, '' end
The SPITF protocol can be used with a dynamic baudrate. If the dynamic baudrate is enabled, the Brick will try to adapt the baudrate for the communication between Bricks and Bricklets according to the amount of data that is transferred.
The baudrate will be increased exponentially if lots of data is sent/received and decreased linearly if little data is sent/received.
This lowers the baudrate in applications where little data is transferred (e.g. a weather station) and increases the robustness. If there is lots of data to transfer (e.g. Thermal Imaging Bricklet) it automatically increases the baudrate as needed.
In cases where some data has to transferred as fast as possible every few seconds (e.g. RS485 Bricklet with a high baudrate but small payload) you may want to turn the dynamic baudrate off to get the highest possible performance.
The maximum value of the baudrate can be set per port with the function BrickDC#set_spitfp_baudrate
. If the dynamic baudrate is disabled, the baudrate as set by BrickDC#set_spitfp_baudrate
will be used statically.
- .. versionadded
-
2.3.5$nbsp;(Firmware)
# File lib/tinkerforge/brick_dc.rb, line 392 def set_spitfp_baudrate_config(enable_dynamic_baudrate, minimum_dynamic_baudrate) check_validity send_request FUNCTION_SET_SPITFP_BAUDRATE_CONFIG, [enable_dynamic_baudrate, minimum_dynamic_baudrate], '? L', 8, '' end
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
.
# File lib/tinkerforge/brick_dc.rb, line 166 def set_velocity(velocity) check_validity send_request FUNCTION_SET_VELOCITY, [velocity], 's', 8, '' end
Writes 32 bytes of firmware to the bricklet attached at the given port. The bytes are written to the position offset * 32.
This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.
# File lib/tinkerforge/brick_dc.rb, line 547 def write_bricklet_plugin(port, offset, chunk) check_validity send_request FUNCTION_WRITE_BRICKLET_PLUGIN, [port, offset, chunk], 'k C C32', 8, '' end