This is the description of the MQTT API bindings for the Performance DC Bricklet. General information and technical specifications for the Performance DC Bricklet are summarized in its hardware description.
An installation guide for the MQTT API bindings is part of their general description.
The example code below is Public Domain (CC0 1.0).
Download (example-configuration.txt)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 | # Change XYZ to the UID of your Performance DC Bricklet
setup:
publish '{"mode": "drive_coast"}' to tinkerforge/request/performance_dc_bricklet/XYZ/set_drive_mode
publish '{"frequency": 10000}' to tinkerforge/request/performance_dc_bricklet/XYZ/set_pwm_frequency # Use PWM frequency of 10 kHz
publish '{"acceleration": 4096, "deceleration": 4096}' to tinkerforge/request/performance_dc_bricklet/XYZ/set_motion # Slow ac-/deceleration (12.5 %/s)
publish '{"velocity": 32767}' to tinkerforge/request/performance_dc_bricklet/XYZ/set_velocity # Full speed forward (100 %)
publish '{"enabled": true}' to tinkerforge/request/performance_dc_bricklet/XYZ/set_enabled # Enable motor power
cleanup:
# If you are done, run this to clean up
# Stop motor before disabling motor power
publish '{"acceleration": 4096, "deceleration": 16384}' to tinkerforge/request/performance_dc_bricklet/XYZ/set_motion # Fast decceleration (50 %/s) for stopping
publish '{"velocity": 0}' to tinkerforge/request/performance_dc_bricklet/XYZ/set_velocity # Request motor stop
wait for 2s # Wait for motor to actually stop: velocity (100 %) / decceleration (50 %/s) = 2 s
publish '{"enabled": false}' to tinkerforge/request/performance_dc_bricklet/XYZ/set_enabled # Disable motor power
|
Download (example-callback.txt)
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 32 33 34 35 36 37 38 39 40 41 42 43 44 45 | # Change XYZ to the UID of your Performance DC Bricklet
setup:
# Use velocity reached callback to swing back and forth
# between full speed forward and full speed backward
subscribe to tinkerforge/callback/performance_dc_bricklet/XYZ/velocity_reached
if a message arrives
# message contains velocity as int
if velocity == 32767
print "Velocity: Full speed forward, now turning backward"
publish '{"velocity": -32767}' to tinkerforge/request/performance_dc_bricklet/XYZ/set_velocity
elseif velocity == -32767
print "Velocity: Full speed backward, now turning forward"
publish '{"velocity": 32767}' to tinkerforge/request/performance_dc_bricklet/XYZ/set_velocity
else
print "Error"
endif
endif
endsubscribe
publish '{"register": true}' to tinkerforge/register/performance_dc_bricklet/XYZ/velocity_reached # Register velocity_reached callback
# Enable velocity reached callback
publish '{"enabled": true}' to tinkerforge/request/performance_dc_bricklet/XYZ/set_velocity_reached_callback_configuration
# The acceleration has to be smaller or equal to the maximum
# acceleration of the DC motor, otherwise the velocity reached
# callback will be called too early
publish '{"acceleration": 4096, "deceleration": 4096}' to tinkerforge/request/performance_dc_bricklet/XYZ/set_motion # Slow acceleration (12.5 %/s)
publish '{"velocity": 32767}' to tinkerforge/request/performance_dc_bricklet/XYZ/set_velocity # Full speed forward (100 %)
# Enable motor power
publish '{"enabled": true}' to tinkerforge/request/performance_dc_bricklet/XYZ/set_enabled
cleanup:
# If you are done, run this to clean up
# Stop motor before disabling motor power
publish '{"acceleration": 4096, "deceleration": 16384}' to tinkerforge/request/performance_dc_bricklet/XYZ/set_motion # Fast decceleration (50 %/s) for stopping
publish '{"velocity": 0}' to tinkerforge/request/performance_dc_bricklet/XYZ/set_velocity # Request motor stop
wait for 2s # Wait for motor to actually stop: velocity (100 %) / decceleration (50 %/s) = 2 s
publish '{"enabled": false}' to tinkerforge/request/performance_dc_bricklet/XYZ/set_enabled # Disable motor power
|
All published payloads to and from the MQTT bindings are in JSON format.
If an error occures, the bindings publish a JSON object containing the error message as member _ERROR
.
It is published on the corresponding response topic: .../response/...
for .../request/...
and .../callback/...
for .../register/...
.
request/
performance_dc_bricklet/
<UID>/
set_enabled
¶Request: |
|
---|---|
Response: |
|
Enables/Disables the driver chip. The driver parameters can be configured (velocity, acceleration, etc) before it is enabled.
request/
performance_dc_bricklet/
<UID>/
get_enabled
¶Request: |
|
---|---|
Response: |
|
Returns true if the driver chip is enabled, false otherwise.
request/
performance_dc_bricklet/
<UID>/
set_velocity
¶Request: |
|
---|---|
Response: |
|
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 request/performance_dc_bricklet/<UID>/set_motion
), 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 request/performance_dc_bricklet/<UID>/set_pwm_frequency
.
request/
performance_dc_bricklet/
<UID>/
get_velocity
¶Request: |
|
---|---|
Response: |
|
Returns the velocity as set by request/performance_dc_bricklet/<UID>/set_velocity
.
request/
performance_dc_bricklet/
<UID>/
get_current_velocity
¶Request: |
|
---|---|
Response: |
|
Returns the current velocity of the motor. This value is different
from request/performance_dc_bricklet/<UID>/get_velocity
whenever the motor is currently accelerating
to a goal set by request/performance_dc_bricklet/<UID>/set_velocity
.
request/
performance_dc_bricklet/
<UID>/
set_motion
¶Request: |
|
---|---|
Response: |
|
Sets the acceleration and deceleration 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 and deceleration is set to 0, there is no speed ramping, i.e. a new velocity is immediately given to the motor.
request/
performance_dc_bricklet/
<UID>/
get_motion
¶Request: |
|
---|---|
Response: |
|
Returns the acceleration/deceleration as set by request/performance_dc_bricklet/<UID>/set_motion
.
request/
performance_dc_bricklet/
<UID>/
full_brake
¶Request: |
|
---|---|
Response: |
|
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 request/performance_dc_bricklet/<UID>/set_velocity
with 0 if you just want to stop the motor.
request/
performance_dc_bricklet/
<UID>/
get_pwm_frequency
¶Request: |
|
---|---|
Response: |
|
Returns the PWM frequency as set by request/performance_dc_bricklet/<UID>/set_pwm_frequency
.
request/
performance_dc_bricklet/
<UID>/
get_power_statistics
¶Request: |
|
---|---|
Response: |
|
Returns input voltage, current usage and temperature of the driver.
request/
performance_dc_bricklet/
<UID>/
set_thermal_shutdown
¶Request: |
|
---|---|
Response: |
|
Sets a temperature threshold that is used for thermal shutdown.
Additionally to this user defined threshold the driver chip will shut down at a temperature of 150°C.
If a thermal shutdown is triggered the driver is disabled and has to be
explicitly re-enabled with request/performance_dc_bricklet/<UID>/set_enabled
.
request/
performance_dc_bricklet/
<UID>/
get_thermal_shutdown
¶Request: |
|
---|---|
Response: |
|
Returns the thermal shutdown temperature as set by request/performance_dc_bricklet/<UID>/set_thermal_shutdown
.
request/
performance_dc_bricklet/
<UID>/
set_gpio_configuration
¶Request: |
|
---|---|
Response: |
|
Sets the GPIO configuration for the given channel.
You can configure a debounce and the deceleration that is used if the action is
configured as normal stop
. See request/performance_dc_bricklet/<UID>/set_gpio_action
.
request/
performance_dc_bricklet/
<UID>/
get_gpio_configuration
¶Request: |
|
---|---|
Response: |
|
Returns the GPIO configuration for a channel as set by request/performance_dc_bricklet/<UID>/set_gpio_configuration
.
request/
performance_dc_bricklet/
<UID>/
set_gpio_action
¶Request: |
|
---|---|
Response: |
|
Sets the GPIO action for the given channel.
The action can be a normal stop, a full brake or a callback. Each for a rising edge or falling edge. The actions are a bitmask they can be used at the same time. You can for example trigger a full brake and a callback at the same time or for rising and falling edge.
The deceleration speed for the normal stop can be configured with
request/performance_dc_bricklet/<UID>/set_gpio_configuration
.
The following symbols are available for this function:
For action:
request/
performance_dc_bricklet/
<UID>/
get_gpio_action
¶Request: |
|
---|---|
Response: |
|
Returns the GPIO action for a channel as set by request/performance_dc_bricklet/<UID>/set_gpio_action
.
The following symbols are available for this function:
For action:
request/
performance_dc_bricklet/
<UID>/
get_gpio_state
¶Request: |
|
---|---|
Response: |
|
Returns the GPIO state for both channels. True if the state is high
and
false if the state is low
.
request/
performance_dc_bricklet/
<UID>/
set_drive_mode
¶Request: |
|
---|---|
Response: |
|
Sets the drive mode. Possible modes are:
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 following symbols are available for this function:
For mode:
request/
performance_dc_bricklet/
<UID>/
get_drive_mode
¶Request: |
|
---|---|
Response: |
|
Returns the drive mode, as set by request/performance_dc_bricklet/<UID>/set_drive_mode
.
The following symbols are available for this function:
For mode:
request/
performance_dc_bricklet/
<UID>/
set_pwm_frequency
¶Request: |
|
---|---|
Response: |
|
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.
request/
performance_dc_bricklet/
<UID>/
set_error_led_config
¶Request: |
|
---|---|
Response: |
|
Configures the error LED to be either turned off, turned on, blink in heartbeat mode or show an error.
If the LED is configured to show errors it has three different states:
The following symbols are available for this function:
For config:
request/
performance_dc_bricklet/
<UID>/
get_error_led_config
¶Request: |
|
---|---|
Response: |
|
Returns the LED configuration as set by request/performance_dc_bricklet/<UID>/set_error_led_config
The following symbols are available for this function:
For config:
request/
performance_dc_bricklet/
<UID>/
set_cw_led_config
¶Request: |
|
---|---|
Response: |
|
Configures the CW LED to be either turned off, turned on, blink in heartbeat mode or if the motor turn clockwise.
The following symbols are available for this function:
For config:
request/
performance_dc_bricklet/
<UID>/
get_cw_led_config
¶Request: |
|
---|---|
Response: |
|
Returns the LED configuration as set by request/performance_dc_bricklet/<UID>/set_cw_led_config
The following symbols are available for this function:
For config:
request/
performance_dc_bricklet/
<UID>/
set_ccw_led_config
¶Request: |
|
---|---|
Response: |
|
Configures the CCW LED to be either turned off, turned on, blink in heartbeat mode or if the motor turn counter-clockwise.
The following symbols are available for this function:
For config:
request/
performance_dc_bricklet/
<UID>/
get_ccw_led_config
¶Request: |
|
---|---|
Response: |
|
Returns the LED configuration as set by request/performance_dc_bricklet/<UID>/set_ccw_led_config
The following symbols are available for this function:
For config:
request/
performance_dc_bricklet/
<UID>/
set_gpio_led_config
¶Request: |
|
---|---|
Response: |
|
Configures the GPIO LED to be either turned off, turned on, blink in heartbeat mode or the GPIO state.
The GPIO LED can be configured for both channels.
The following symbols are available for this function:
For config:
request/
performance_dc_bricklet/
<UID>/
get_gpio_led_config
¶Request: |
|
---|---|
Response: |
|
Returns the LED configuration as set by request/performance_dc_bricklet/<UID>/set_gpio_led_config
The following symbols are available for this function:
For config:
request/
performance_dc_bricklet/
<UID>/
get_spitfp_error_count
¶Request: |
|
---|---|
Response: |
|
Returns the error count for the communication between Brick and Bricklet.
The errors are divided into
The errors counts are for errors that occur on the Bricklet side. All Bricks have a similar function that returns the errors on the Brick side.
request/
performance_dc_bricklet/
<UID>/
set_status_led_config
¶Request: |
|
---|---|
Response: |
|
Sets the status LED configuration. By default the LED shows communication traffic between Brick and Bricklet, it flickers once for every 10 received data packets.
You can also turn the LED permanently on/off or show a heartbeat.
If the Bricklet is in bootloader mode, the LED is will show heartbeat by default.
The following symbols are available for this function:
For config:
request/
performance_dc_bricklet/
<UID>/
get_status_led_config
¶Request: |
|
---|---|
Response: |
|
Returns the configuration as set by request/performance_dc_bricklet/<UID>/set_status_led_config
The following symbols are available for this function:
For config:
request/
performance_dc_bricklet/
<UID>/
get_chip_temperature
¶Request: |
|
---|---|
Response: |
|
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 bad accuracy. Practically it is only useful as an indicator for temperature changes.
request/
performance_dc_bricklet/
<UID>/
reset
¶Request: |
|
---|---|
Response: |
|
Calling this function will reset the Bricklet. All configurations will be lost.
After a reset you have to create new device objects, calling functions on the existing ones will result in undefined behavior!
request/
performance_dc_bricklet/
<UID>/
get_identity
¶Request: |
|
---|---|
Response: |
|
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 at position 'z'.
The device identifier numbers can be found here. If symbolic output is not disabled, the device identifier is mapped to the corresponding name in the format used in topics.
The display name contains the Performance DC's name in a human readable form.
request/
performance_dc_bricklet/
<UID>/
set_emergency_shutdown_callback_configuration
¶Request: |
|
---|---|
Response: |
|
Enable/Disable register/performance_dc_bricklet/<UID>/emergency_shutdown
callback.
request/
performance_dc_bricklet/
<UID>/
get_emergency_shutdown_callback_configuration
¶Request: |
|
---|---|
Response: |
|
Returns the callback configuration as set by
request/performance_dc_bricklet/<UID>/set_emergency_shutdown_callback_configuration
.
request/
performance_dc_bricklet/
<UID>/
set_velocity_reached_callback_configuration
¶Request: |
|
---|---|
Response: |
|
Enable/Disable register/performance_dc_bricklet/<UID>/velocity_reached
callback.
request/
performance_dc_bricklet/
<UID>/
get_velocity_reached_callback_configuration
¶Request: |
|
---|---|
Response: |
|
Returns the callback configuration as set by
request/performance_dc_bricklet/<UID>/set_velocity_reached_callback_configuration
.
request/
performance_dc_bricklet/
<UID>/
set_current_velocity_callback_configuration
¶Request: |
|
---|---|
Response: |
|
The period is the period with which the register/performance_dc_bricklet/<UID>/current_velocity
callback is triggered periodically. A value of 0 turns the callback off.
If the value has to change-parameter is set to true, the callback is only triggered after the value has changed. If the value didn't change within the period, the callback is triggered immediately on change.
If it is set to false, the callback is continuously triggered with the period, independent of the value.
request/
performance_dc_bricklet/
<UID>/
get_current_velocity_callback_configuration
¶Request: |
|
---|---|
Response: |
|
Returns the callback configuration as set by
request/performance_dc_bricklet/<UID>/set_current_velocity_callback_configuration
.
Callbacks can be registered to receive
time critical or recurring data from the device. The registration is done
with the corresponding .../register/...
topic and an optional suffix.
This suffix can be used to deregister the callback later.
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.
register/
performance_dc_bricklet/
<UID>/
emergency_shutdown
¶Register Request: |
|
---|---|
Callback Response: |
|
A callback can be registered for this event by publishing to the .../register/performance_dc_bricklet/<UID>/emergency_shutdown[/<SUFFIX>]
topic with the payload "true".
An added callback can be removed by publishing to the same topic with the payload "false".
To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.
If the callback is triggered, a message with it's payload is published under the corresponding .../callback/performance_dc_bricklet/<UID>/emergency_shutdown[/<SUFFIX>]
topic for each registered suffix.
This callback is triggered if either the current consumption
is too high or the temperature of the driver chip is too high
(above 150°C) or the user defined thermal shutdown is triggered (see request/performance_dc_bricklet/<UID>/set_thermal_shutdown
).
n case of a voltage below 6V (input voltage) this
callback is triggered as well.
If this callback is triggered, the driver chip gets disabled at the same time.
That means, request/performance_dc_bricklet/<UID>/set_enabled
has to be called to drive the motor again.
register/
performance_dc_bricklet/
<UID>/
velocity_reached
¶Register Request: |
|
---|---|
Callback Response: |
|
A callback can be registered for this event by publishing to the .../register/performance_dc_bricklet/<UID>/velocity_reached[/<SUFFIX>]
topic with the payload "true".
An added callback can be removed by publishing to the same topic with the payload "false".
To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.
If the callback is triggered, a message with it's payload is published under the corresponding .../callback/performance_dc_bricklet/<UID>/velocity_reached[/<SUFFIX>]
topic for each registered suffix.
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 register/performance_dc_bricklet/<UID>/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 request/performance_dc_bricklet/<UID>/set_motion
) 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.
register/
performance_dc_bricklet/
<UID>/
current_velocity
¶Register Request: |
|
---|---|
Callback Response: |
|
A callback can be registered for this event by publishing to the .../register/performance_dc_bricklet/<UID>/current_velocity[/<SUFFIX>]
topic with the payload "true".
An added callback can be removed by publishing to the same topic with the payload "false".
To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.
If the callback is triggered, a message with it's payload is published under the corresponding .../callback/performance_dc_bricklet/<UID>/current_velocity[/<SUFFIX>]
topic for each registered suffix.
This callback is triggered with the period that is set by
request/performance_dc_bricklet/<UID>/set_current_velocity_callback_configuration
. The callback payload is the current
velocity used by the motor.
The register/performance_dc_bricklet/<UID>/current_velocity
callback is only triggered after the set period
if there is a change in the velocity.
register/
performance_dc_bricklet/
<UID>/
gpio_state
¶Register Request: |
|
---|---|
Callback Response: |
|
A callback can be registered for this event by publishing to the .../register/performance_dc_bricklet/<UID>/gpio_state[/<SUFFIX>]
topic with the payload "true".
An added callback can be removed by publishing to the same topic with the payload "false".
To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.
If the callback is triggered, a message with it's payload is published under the corresponding .../callback/performance_dc_bricklet/<UID>/gpio_state[/<SUFFIX>]
topic for each registered suffix.
This callback is triggered by GPIO changes if it is activated through request/performance_dc_bricklet/<UID>/set_gpio_action
.
New in version 2.0.1 (Plugin).
Internal functions are used for maintenance tasks such as flashing a new firmware of changing the UID of a Bricklet. These task should be performed using Brick Viewer instead of using the internal functions directly.
request/
performance_dc_bricklet/
<UID>/
set_bootloader_mode
¶Request: |
|
---|---|
Response: |
|
Sets the bootloader mode and returns the status after the requested mode change was instigated.
You can change from bootloader mode to firmware mode and vice versa. A change from bootloader mode to firmware mode will only take place if the entry function, device identifier and CRC are present and correct.
This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.
The following symbols are available for this function:
For mode:
For status:
request/
performance_dc_bricklet/
<UID>/
get_bootloader_mode
¶Request: |
|
---|---|
Response: |
|
Returns the current bootloader mode, see request/performance_dc_bricklet/<UID>/set_bootloader_mode
.
The following symbols are available for this function:
For mode:
request/
performance_dc_bricklet/
<UID>/
set_write_firmware_pointer
¶Request: |
|
---|---|
Response: |
|
Sets the firmware pointer for request/performance_dc_bricklet/<UID>/write_firmware
. The pointer has
to be increased by chunks of size 64. The data is written to flash
every 4 chunks (which equals to one page of size 256).
This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.
request/
performance_dc_bricklet/
<UID>/
write_firmware
¶Request: |
|
---|---|
Response: |
|
Writes 64 Bytes of firmware at the position as written by
request/performance_dc_bricklet/<UID>/set_write_firmware_pointer
before. The firmware is written
to flash every 4 chunks.
You can only write firmware in bootloader mode.
This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.
request/
performance_dc_bricklet/
<UID>/
write_uid
¶Request: |
|
---|---|
Response: |
|
Writes a new UID into flash. If you want to set a new UID you have to decode the Base58 encoded UID string into an integer first.
We recommend that you use Brick Viewer to change the UID.
request/
performance_dc_bricklet/
<UID>/
read_uid
¶Request: |
|
---|---|
Response: |
|
Returns the current UID as an integer. Encode as Base58 to get the usual string version.