MQTT - Silent Stepper Brick

This is the description of the MQTT API bindings for the Silent Stepper Brick. General information and technical specifications for the Silent Stepper Brick are summarized in its hardware description.

An installation guide for the MQTT API bindings is part of their general description.

Examples

The example code below is Public Domain (CC0 1.0).

Configuration

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
# Change XXYYZZ to the UID of your Silent Stepper Brick

setup:
    publish '{"current": 800}' to tinkerforge/request/silent_stepper_brick/XXYYZZ/set_motor_current  # 800mA
    
    publish '{"step_resolution": "8", "interpolation": true}' to tinkerforge/request/silent_stepper_brick/XXYYZZ/set_step_configuration  # 1/8 steps (interpolated)
    
    publish '{"velocity": 2000}' to tinkerforge/request/silent_stepper_brick/XXYYZZ/set_max_velocity  # Velocity 2000 steps/s
    
    # Slow acceleration (500 steps/s^2),
    # Fast deacceleration (5000 steps/s^2)
    publish '{"acceleration": 500, "deacceleration": 5000}' to tinkerforge/request/silent_stepper_brick/XXYYZZ/set_speed_ramping 
    
    
    
    publish '' to tinkerforge/request/silent_stepper_brick/XXYYZZ/enable  # Enable motor power
    
    publish '{"steps": 60000}' to tinkerforge/request/silent_stepper_brick/XXYYZZ/set_steps  # Drive 60000 steps forward

cleanup:
    # If you are done, run this to clean up
    publish '' to tinkerforge/request/silent_stepper_brick/XXYYZZ/disable 

Callback

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
# Change XXYYZZ to the UID of your Silent Stepper Brick

setup:
    # Use position reached callback to program random movement
    subscribe to tinkerforge/callback/silent_stepper_brick/XXYYZZ/position_reached
       if a message arives
            # message contains the current position as int
            generate random numbers r,
                    steps [1000;5000],
                    vel [200; 2000],
                    acc [100; 1000]
                and dec [100; 1000]
                
            if r is even
                # Driving forward        
            else
                # Driving backward
                set steps to -steps
            endif
            publish '{"acceleration": acc, "deceleration": dec}' to tinkerforge/request/silent_stepper_brick/XXYYZZ/set_speed_ramping
            publish '{"velocity": vel}' to tinkerforge/request/silent_stepper_brick/XXYYZZ/set_max_velocity
            publish '{"steps": steps}' to tinkerforge/request/silent_stepper_brick/XXYYZZ/set_steps
        endif
    endsubscribe
    
    publish '{"register": true}' to tinkerforge/register/silent_stepper_brick/XXYYZZ/position_reached # Register position_reached callback
    
    publish '{"step_resolution": "8", "interpolation": true}' to tinkerforge/request/silent_stepper_brick/XXYYZZ/set_step_configuration  # 1/8 steps (interpolated)
    publish '' to tinkerforge/request/silent_stepper_brick/XXYYZZ/enable  # Enable motor power
    publish '{"steps": 1}' to tinkerforge/request/silent_stepper_brick/XXYYZZ/set_steps  # Drive one step forward to get things going

cleanup:
    # If you are done, run this to clean up
    publish '' to tinkerforge/request/silent_stepper_brick/XXYYZZ/disable 

API

All published payload to an from the MQTT bindings is in the JSON format.

If an error occures, the bindings publish a JSON object containing the error message as attribute "_ERROR". It is published on the corresponding response topic: .../response/... for .../request/... and .../callback/... for .../register/....

Basic Functions

request/silent_stepper_brick/<UID>/set_max_velocity
Request payload:
 
  • velocity -- int

Sets the maximum velocity of the stepper motor in steps per second. This function does not start the motor, it merely sets the maximum velocity the stepper motor is accelerated to. To get the motor running use either request/silent_stepper_brick/<UID>/set_target_position, request/silent_stepper_brick/<UID>/set_steps, request/silent_stepper_brick/<UID>/drive_forward or request/silent_stepper_brick/<UID>/drive_backward.

request/silent_stepper_brick/<UID>/get_max_velocity
Response payload:
 
  • velocity -- int

Returns the velocity as set by request/silent_stepper_brick/<UID>/set_max_velocity.

request/silent_stepper_brick/<UID>/get_current_velocity
Response payload:
 
  • velocity -- int

Returns the current velocity of the stepper motor in steps per second.

request/silent_stepper_brick/<UID>/set_speed_ramping
Request payload:
 
  • acceleration -- int
  • deacceleration -- int

Sets the acceleration and deacceleration of the stepper motor. The values are given in steps/s². An acceleration of 1000 means, that every second the velocity is increased by 1000 steps/s.

For example: If the current velocity is 0 and you want to accelerate to a velocity of 8000 steps/s in 10 seconds, you should set an acceleration of 800 steps/s².

An acceleration/deacceleration of 0 means instantaneous acceleration/deacceleration (not recommended)

The default value is 1000 for both

request/silent_stepper_brick/<UID>/get_speed_ramping
Response payload:
 
  • acceleration -- int
  • deacceleration -- int

Returns the acceleration and deacceleration as set by request/silent_stepper_brick/<UID>/set_speed_ramping.

request/silent_stepper_brick/<UID>/full_brake

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/silent_stepper_brick/<UID>/stop if you just want to stop the motor.

request/silent_stepper_brick/<UID>/set_steps
Request payload:
 
  • steps -- int

Sets the number of steps the stepper motor should run. Positive values will drive the motor forward and negative values backward. The velocity, acceleration and deacceleration as set by request/silent_stepper_brick/<UID>/set_max_velocity and request/silent_stepper_brick/<UID>/set_speed_ramping will be used.

request/silent_stepper_brick/<UID>/get_steps
Response payload:
 
  • steps -- int

Returns the last steps as set by request/silent_stepper_brick/<UID>/set_steps.

request/silent_stepper_brick/<UID>/get_remaining_steps
Response payload:
 
  • steps -- int

Returns the remaining steps of the last call of request/silent_stepper_brick/<UID>/set_steps. For example, if request/silent_stepper_brick/<UID>/set_steps is called with 2000 and request/silent_stepper_brick/<UID>/get_remaining_steps is called after the motor has run for 500 steps, it will return 1500.

request/silent_stepper_brick/<UID>/drive_forward

Drives the stepper motor forward until request/silent_stepper_brick/<UID>/drive_backward or request/silent_stepper_brick/<UID>/stop is called. The velocity, acceleration and deacceleration as set by request/silent_stepper_brick/<UID>/set_max_velocity and request/silent_stepper_brick/<UID>/set_speed_ramping will be used.

request/silent_stepper_brick/<UID>/drive_backward

Drives the stepper motor backward until request/silent_stepper_brick/<UID>/drive_forward or request/silent_stepper_brick/<UID>/stop is triggered. The velocity, acceleration and deacceleration as set by request/silent_stepper_brick/<UID>/set_max_velocity and request/silent_stepper_brick/<UID>/set_speed_ramping will be used.

request/silent_stepper_brick/<UID>/stop

Stops the stepper motor with the deacceleration as set by request/silent_stepper_brick/<UID>/set_speed_ramping.

request/silent_stepper_brick/<UID>/set_motor_current
Request payload:
 
  • current -- int

Sets the current in mA with which the motor will be driven. The minimum value is 360mA, the maximum value 1640mA and the default value is 800mA.

Warning

Do not set this value above the specifications of your stepper motor. Otherwise it may damage your motor.

request/silent_stepper_brick/<UID>/get_motor_current
Response payload:
 
  • current -- int

Returns the current as set by request/silent_stepper_brick/<UID>/set_motor_current.

request/silent_stepper_brick/<UID>/enable

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

request/silent_stepper_brick/<UID>/disable

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

request/silent_stepper_brick/<UID>/is_enabled
Response payload:
 
  • enabled -- bool

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

request/silent_stepper_brick/<UID>/set_basic_configuration
Request payload:
 
  • standstill_current -- int
  • motor_run_current -- int
  • standstill_delay_time -- int
  • power_down_time -- int
  • stealth_threshold -- int
  • coolstep_threshold -- int
  • classic_threshold -- int
  • high_velocity_chopper_mode -- bool

Sets the basic configuration parameters for the different modes (Stealth, Coolstep, Classic).

  • Standstill Current: This value can be used to lower the current during stand still. This might be reasonable to reduce the heating of the motor and the Brick. When the motor is in standstill the configured motor phase current will be driven until the configured Power Down Time is elapsed. After that the phase current will be reduced to the standstill current. The elapsed time for this reduction can be configured with the Standstill Delay Time. The unit is in mA and the maximum allowed value is the configured maximum motor current (see request/silent_stepper_brick/<UID>/set_motor_current).
  • Motor Run Current: The value sets the motor current when the motor is running. Use a value of at least one half of the global maximum motor current for a good microstep performance. The unit is in mA and the maximum allowed value is the current motor current. The API maps the entered value to 1/32 ... 32/32 of the maximum motor current. This value should be used to change the motor current during motor movement, whereas the global maximum motor current should not be changed while the motor is moving (see request/silent_stepper_brick/<UID>/set_motor_current).
  • Standstill Delay Time: Controls the duration for motor power down after a motion as soon as standstill is detected and the Power Down Time is expired. A high Standstill Delay Time results in a smooth transition that avoids motor jerk during power down. The value range is 0 to 307ms
  • Power Down Time: Sets the delay time after a stand still. The value range is 0 to 5222ms.
  • Stealth Threshold: Sets the upper threshold for Stealth mode in steps/s. The value range is 0-65536 steps/s. If the velocity of the motor goes above this value, Stealth mode is turned off. Otherwise it is turned on. In Stealth mode the torque declines with high speed.
  • Coolstep Threshold: Sets the lower threshold for Coolstep mode in steps/s. The value range is 0-65536 steps/s. The Coolstep Threshold needs to be above the Stealth Threshold.
  • Classic Threshold: Sets the lower threshold for classic mode. The value range is 0-65536 steps/s. In classic mode the stepper becomes more noisy, but the torque is maximized.
  • High Velocity Shopper Mode: If High Velocity Shopper Mode is enabled, the stepper control is optimized to run the stepper motors at high velocities.

If you want to use all three thresholds make sure that Stealth Threshold < Coolstep Threshold < Classic Threshold.

The default values are:

  • Standstill Current: 200
  • Motor Run Current: 800
  • Standstill Delay Time: 0
  • Power Down Time: 1000
  • Stealth Threshold: 500
  • Coolstep Threshold: 500
  • Classic Threshold: 1000
  • High Velocity Shopper Mode: false
request/silent_stepper_brick/<UID>/get_basic_configuration
Response payload:
 
  • standstill_current -- int
  • motor_run_current -- int
  • standstill_delay_time -- int
  • power_down_time -- int
  • stealth_threshold -- int
  • coolstep_threshold -- int
  • classic_threshold -- int
  • high_velocity_chopper_mode -- bool

Returns the configuration as set by request/silent_stepper_brick/<UID>/set_basic_configuration.

Advanced Functions

request/silent_stepper_brick/<UID>/set_current_position
Request payload:
 
  • position -- int

Sets the current steps of the internal step counter. This can be used to set the current position to 0 when some kind of starting position is reached (e.g. when a CNC machine reaches a corner).

request/silent_stepper_brick/<UID>/get_current_position
Response payload:
 
  • position -- int

Returns the current position of the stepper motor in steps. On startup the position is 0. The steps are counted with all possible driving functions (request/silent_stepper_brick/<UID>/set_target_position, request/silent_stepper_brick/<UID>/set_steps, request/silent_stepper_brick/<UID>/drive_forward or request/silent_stepper_brick/<UID>/drive_backward). It also is possible to reset the steps to 0 or set them to any other desired value with request/silent_stepper_brick/<UID>/set_current_position.

request/silent_stepper_brick/<UID>/set_target_position
Request payload:
 
  • position -- int

Sets the target position of the stepper motor in steps. For example, if the current position of the motor is 500 and request/silent_stepper_brick/<UID>/set_target_position is called with 1000, the stepper motor will drive 500 steps forward. It will use the velocity, acceleration and deacceleration as set by request/silent_stepper_brick/<UID>/set_max_velocity and request/silent_stepper_brick/<UID>/set_speed_ramping.

A call of request/silent_stepper_brick/<UID>/set_target_position with the parameter x is equivalent to a call of request/silent_stepper_brick/<UID>/set_steps with the parameter (x - request/silent_stepper_brick/<UID>/get_current_position).

request/silent_stepper_brick/<UID>/get_target_position
Response payload:
 
  • position -- int

Returns the last target position as set by request/silent_stepper_brick/<UID>/set_target_position.

request/silent_stepper_brick/<UID>/set_step_configuration
Request payload:
 
  • step_resolution -- int (has symbols)
  • interpolation -- bool

Sets the step resolution from full-step up to 1/256-step.

If interpolation is turned on, the Silent Stepper Brick will always interpolate your step inputs as 1/256-step. If you use full-step mode with interpolation, each step will generate 256 1/256 steps.

For maximum torque use full-step without interpolation. For maximum resolution use 1/256-step. Turn interpolation on to make the Stepper driving less noisy.

If you often change the speed with high acceleration you should turn the interpolation off.

The default is 1/256-step with interpolation on.

The following symbols are available for this function:

for step_resolution:

  • "1" = 8
  • "2" = 7
  • "4" = 6
  • "8" = 5
  • "16" = 4
  • "32" = 3
  • "64" = 2
  • "128" = 1
  • "256" = 0
request/silent_stepper_brick/<UID>/get_step_configuration
Response payload:
 
  • step_resolution -- int (has symbols)
  • interpolation -- bool

Returns the step mode as set by request/silent_stepper_brick/<UID>/set_step_configuration.

The following symbols are available for this function:

for step_resolution:

  • "1" = 8
  • "2" = 7
  • "4" = 6
  • "8" = 5
  • "16" = 4
  • "32" = 3
  • "64" = 2
  • "128" = 1
  • "256" = 0
request/silent_stepper_brick/<UID>/get_stack_input_voltage
Response payload:
 
  • voltage -- int

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.

request/silent_stepper_brick/<UID>/get_external_input_voltage
Response payload:
 
  • voltage -- int

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

request/silent_stepper_brick/<UID>/set_spreadcycle_configuration
Request payload:
 
  • slow_decay_duration -- int
  • enable_random_slow_decay -- bool
  • fast_decay_duration -- int
  • hysteresis_start_value -- int
  • hysteresis_end_value -- int
  • sine_wave_offset -- int
  • chopper_mode -- int (has symbols)
  • comparator_blank_time -- int
  • fast_decay_without_comparator -- bool

Note: If you don't know what any of this means you can very likely keep all of the values as default!

Sets the Spreadcycle configuration parameters. Spreadcycle is a chopper algorithm which actively controls the motor current flow. More information can be found in the TMC2130 datasheet on page 47 (7 spreadCycle and Classic Chopper).

  • Slow Decay Duration: Controls duration of off time setting of slow decay phase. The value range is 0-15. 0 = driver disabled, all bridges off. Use 1 only with Comparator Blank time >= 2.

  • Enable Random Slow Decay: Set to false to fix chopper off time as set by Slow Decay Duration. If you set it to true, Decay Duration is randomly modulated.

  • Fast Decay Duration: Sets the fast decay duration. The value range is 0-15. This parameters is only used if the Chopper Mode is set to Fast Decay.

  • Hysteresis Start Value: Sets the hysteresis start value. The value range is 0-7. This parameter is only used if the Chopper Mode is set to Spread Cycle.

  • Hysteresis End Value: Sets the hysteresis end value. The value range is -3 to 12. This parameter is only used if the Chopper Mode is set to Spread Cycle.

  • Sine Wave Offset: Sets the sine wave offset. The value range is -3 to 12. This parameters is only used if the Chopper Mode is set to Fast Decay. 1/512 of the value becomes added to the absolute value of the sine wave.

  • Chopper Mode: 0 = Spread Cycle, 1 = Fast Decay.

  • Comparator Blank Time: Sets the blank time of the comparator. Available values are

    • 0 = 16 clocks,
    • 1 = 24 clocks,
    • 2 = 36 clocks and
    • 3 = 54 clocks.

    A value of 1 or 2 is recommended for most applications.

  • Fast Decay Without Comparator: If set to true the current comparator usage for termination of the fast decay cycle is disabled.

The default values are:

  • Slow Decay Duration: 4
  • Enable Random Slow Decay: 0
  • Fast Decay Duration: 0
  • Hysteresis Start Value: 0
  • Hysteresis End Value: 0
  • Sine Wave Offset: 0
  • Chopper Mode: 0
  • Comparator Blank Time: 1
  • Fast Decay Without Comparator: false

The following symbols are available for this function:

for chopper_mode:

  • "SpreadCycle" = 0
  • "FastDecay" = 1
request/silent_stepper_brick/<UID>/get_spreadcycle_configuration
Response payload:
 
  • slow_decay_duration -- int
  • enable_random_slow_decay -- bool
  • fast_decay_duration -- int
  • hysteresis_start_value -- int
  • hysteresis_end_value -- int
  • sine_wave_offset -- int
  • chopper_mode -- int (has symbols)
  • comparator_blank_time -- int
  • fast_decay_without_comparator -- bool

Returns the configuration as set by request/silent_stepper_brick/<UID>/set_basic_configuration.

The following symbols are available for this function:

for chopper_mode:

  • "SpreadCycle" = 0
  • "FastDecay" = 1
request/silent_stepper_brick/<UID>/set_stealth_configuration
Request payload:
 
  • enable_stealth -- bool
  • amplitude -- int
  • gradient -- int
  • enable_autoscale -- bool
  • force_symmetric -- bool
  • freewheel_mode -- int (has symbols)

Note: If you don't know what any of this means you can very likely keep all of the values as default!

Sets the configuration relevant for Stealth mode.

  • Enable Stealth: If set to true the stealth mode is enabled, if set to false the stealth mode is disabled, even if the speed is below the threshold set in request/silent_stepper_brick/<UID>/set_basic_configuration.
  • Amplitude: If autoscale is disabled, the PWM amplitude is scaled by this value. If autoscale is enabled, this value defines the maximum PWM amplitude change per half wave. The value range is 0-255.
  • Gradient: If autoscale is disabled, the PWM gradient is scaled by this value. If autoscale is enabled, this value defines the maximum PWM gradient. With autoscale a value above 64 is recommended, otherwise the regulation might not be able to measure the current. The value range is 0-255.
  • Enable Autoscale: If set to true, automatic current control is used. Otherwise the user defined amplitude and gradient are used.
  • Force Symmetric: If true, A symmetric PWM cycle is enforced. Otherwise the PWM value may change within each PWM cycle.
  • Freewheel Mode: The freewheel mode defines the behavior in stand still if the Standstill Current (see request/silent_stepper_brick/<UID>/set_basic_configuration) is set to 0.

The default values are:

  • Enable Stealth: true
  • Amplitude: 128
  • Gradient: 4
  • Enable Autoscale: true
  • Force Symmetric: false
  • Freewheel Mode: 0 (Normal)

The following symbols are available for this function:

for freewheel_mode:

  • "Normal" = 0
  • "Freewheeling" = 1
  • "CoilShortLS" = 2
  • "CoilShortHS" = 3
request/silent_stepper_brick/<UID>/get_stealth_configuration
Response payload:
 
  • enable_stealth -- bool
  • amplitude -- int
  • gradient -- int
  • enable_autoscale -- bool
  • force_symmetric -- bool
  • freewheel_mode -- int (has symbols)

Returns the configuration as set by request/silent_stepper_brick/<UID>/set_stealth_configuration.

The following symbols are available for this function:

for freewheel_mode:

  • "Normal" = 0
  • "Freewheeling" = 1
  • "CoilShortLS" = 2
  • "CoilShortHS" = 3
request/silent_stepper_brick/<UID>/set_coolstep_configuration
Request payload:
 
  • minimum_stallguard_value -- int
  • maximum_stallguard_value -- int
  • current_up_step_width -- int (has symbols)
  • current_down_step_width -- int (has symbols)
  • minimum_current -- int (has symbols)
  • stallguard_threshold_value -- int
  • stallguard_mode -- int (has symbols)

Note: If you don't know what any of this means you can very likely keep all of the values as default!

Sets the configuration relevant for Coolstep.

  • Minimum Stallguard Value: If the Stallguard result falls below this value*32, the motor current is increased to reduce motor load angle. The value range is 0-15. A value of 0 turns Coolstep off.
  • Maximum Stallguard Value: If the Stallguard result goes above (Min Stallguard Value + Max Stallguard Value + 1) * 32, the motor current is decreased to save energy.
  • Current Up Step Width: Sets the up step increment per Stallguard value. The value range is 0-3, corresponding to the increments 1, 2, 4 and 8.
  • Current Down Step Width: Sets the down step decrement per Stallguard value. The value range is 0-3, corresponding to the decrements 1, 2, 8 and 16.
  • Minimum Current: Sets the minimum current for Coolstep current control. You can choose between half and quarter of the run current.
  • Stallguard Threshold Value: Sets the level for stall output (see request/silent_stepper_brick/<UID>/get_driver_status). The value range is -64 to +63. A lower value gives a higher sensitivity. You have to find a suitable value for your motor by trial and error, 0 works for most motors.
  • Stallguard Mode: Set to 0 for standard resolution or 1 for filtered mode. In filtered mode the Stallguard signal will be updated every four full-steps.

The default values are:

  • Minimum Stallguard Value: 2
  • Maximum Stallguard Value: 10
  • Current Up Step Width: 0
  • Current Down Step Width: 0
  • Minimum Current: 0
  • Stallguard Threshold Value: 0
  • Stallguard Mode: 0

The following symbols are available for this function:

for current_up_step_width:

  • "1" = 0
  • "2" = 1
  • "4" = 2
  • "8" = 3

for current_down_step_width:

  • "1" = 0
  • "2" = 1
  • "8" = 2
  • "32" = 3

for minimum_current:

  • "Half" = 0
  • "Quarter" = 1

for stallguard_mode:

  • "Standard" = 0
  • "Filtered" = 1
request/silent_stepper_brick/<UID>/get_coolstep_configuration
Response payload:
 
  • minimum_stallguard_value -- int
  • maximum_stallguard_value -- int
  • current_up_step_width -- int (has symbols)
  • current_down_step_width -- int (has symbols)
  • minimum_current -- int (has symbols)
  • stallguard_threshold_value -- int
  • stallguard_mode -- int (has symbols)

Returns the configuration as set by request/silent_stepper_brick/<UID>/set_coolstep_configuration.

The following symbols are available for this function:

for current_up_step_width:

  • "1" = 0
  • "2" = 1
  • "4" = 2
  • "8" = 3

for current_down_step_width:

  • "1" = 0
  • "2" = 1
  • "8" = 2
  • "32" = 3

for minimum_current:

  • "Half" = 0
  • "Quarter" = 1

for stallguard_mode:

  • "Standard" = 0
  • "Filtered" = 1
request/silent_stepper_brick/<UID>/set_misc_configuration
Request payload:
 
  • disable_short_to_ground_protection -- bool
  • synchronize_phase_frequency -- int

Note: If you don't know what any of this means you can very likely keep all of the values as default!

Sets miscellaneous configuration parameters.

  • Disable Short To Ground Protection: Set to false to enable short to ground protection, otherwise it is disabled.
  • Synchronize Phase Frequency: With this parameter you can synchronize the chopper for both phases of a two phase motor to avoid the occurrence of a beat. The value range is 0-15. If set to 0, the synchronization is turned off. Otherwise the synchronization is done through the formula f_sync = f_clk/(value*64). In Classic Mode the synchronization is automatically switched off. f_clk is 12.8MHz.

The default values are:

  • Disable Short To Ground Protection: 0
  • Synchronize Phase Frequency: 0
request/silent_stepper_brick/<UID>/get_misc_configuration
Response payload:
 
  • disable_short_to_ground_protection -- bool
  • synchronize_phase_frequency -- int

Returns the configuration as set by request/silent_stepper_brick/<UID>/set_misc_configuration.

request/silent_stepper_brick/<UID>/get_driver_status
Response payload:
 
  • open_load -- int (has symbols)
  • short_to_ground -- int (has symbols)
  • over_temperature -- int (has symbols)
  • motor_stalled -- bool
  • actual_motor_current -- int
  • full_step_active -- bool
  • stallguard_result -- int
  • stealth_voltage_amplitude -- int

Returns the current driver status.

  • Open Load: Indicates if an open load is present on phase A, B or both. This could mean that there is a problem with the wiring of the motor. False detection can occur in fast motion as well as during stand still.
  • Short To Ground: Indicates if a short to ground is present on phase A, B or both. If this is detected the driver automatically becomes disabled and stays disabled until it is enabled again manually.
  • Over Temperature: The over temperature indicator switches to "Warning" if the driver IC warms up. The warning flag is expected during long duration stepper uses. If the temperature limit is reached the indicator switches to "Limit". In this case the driver becomes disabled until it cools down again.
  • Motor Stalled: Is true if a motor stall was detected.
  • Actual Motor Current: Indicates the actual current control scaling as used in Coolstep mode. The returned value is between 0 and 31. It represents a multiplier of 1/32 to 32/32 of the Motor Run Current as set by request/silent_stepper_brick/<UID>/set_basic_configuration. Example: If a Motor Run Current of 1000mA was set and the returned value is 15, the Actual Motor Current is 16/32*1000mA = 500mA.
  • Stallguard Result: Indicates the load of the motor. A lower value signals a higher load. Per trial and error you can find out which value corresponds to a suitable torque for the velocity used in your application. After that you can use this threshold value to find out if a motor stall becomes probable and react on it (e.g. decrease velocity). During stand still this value can not be used for stall detection, it shows the chopper on-time for motor coil A.
  • Stealth Voltage Amplitude: Shows the actual PWM scaling. In Stealth mode it can be used to detect motor load and stall if autoscale is enabled (see request/silent_stepper_brick/<UID>/set_stealth_configuration).

The following symbols are available for this function:

for open_load:

  • "None" = 0
  • "PhaseA" = 1
  • "PhaseB" = 2
  • "PhaseAB" = 3

for short_to_ground:

  • "None" = 0
  • "PhaseA" = 1
  • "PhaseB" = 2
  • "PhaseAB" = 3

for over_temperature:

  • "None" = 0
  • "Warning" = 1
  • "Limit" = 2
request/silent_stepper_brick/<UID>/set_time_base
Request payload:
 
  • time_base -- int

Sets the time base of the velocity and the acceleration of the Silent Stepper Brick (in seconds).

For example, if you want to make one step every 1.5 seconds, you can set the time base to 15 and the velocity to 10. Now the velocity is 10steps/15s = 1steps/1.5s.

The default value is 1.

request/silent_stepper_brick/<UID>/get_time_base
Response payload:
 
  • time_base -- int

Returns the time base as set by request/silent_stepper_brick/<UID>/set_time_base.

request/silent_stepper_brick/<UID>/get_all_data
Response payload:
 
  • current_velocity -- int
  • current_position -- int
  • remaining_steps -- int
  • stack_voltage -- int
  • external_voltage -- int
  • current_consumption -- int

Returns the following parameters: The current velocity, the current position, the remaining steps, the stack voltage, the external voltage and the current consumption of the stepper motor.

The current consumption is calculated by multiplying the Actual Motor Current value (see request/silent_stepper_brick/<UID>/set_basic_configuration) with the Motor Run Current (see request/silent_stepper_brick/<UID>/get_driver_status). This is an internal calculation of the driver, not an independent external measurement.

The current consumption calculation was broken up to firmware 2.0.1, it is fixed since firmware 2.0.2.

There is also a callback for this function, see register/silent_stepper_brick/<UID>/all_data callback.

request/silent_stepper_brick/<UID>/set_spitfp_baudrate_config
Request payload:
 
  • enable_dynamic_baudrate -- bool
  • minimum_dynamic_baudrate -- int

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 send/received and decreased linearly if little data is send/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 request/silent_stepper_brick/<UID>/set_spitfp_baudrate. If the dynamic baudrate is disabled, the baudrate as set by request/silent_stepper_brick/<UID>/set_spitfp_baudrate will be used statically.

The minimum dynamic baudrate has a value range of 400000 to 2000000 baud.

By default dynamic baudrate is enabled and the minimum dynamic baudrate is 400000.

New in version 2.0.4 (Firmware).

request/silent_stepper_brick/<UID>/get_spitfp_baudrate_config
Response payload:
 
  • enable_dynamic_baudrate -- bool
  • minimum_dynamic_baudrate -- int

Returns the baudrate config, see request/silent_stepper_brick/<UID>/set_spitfp_baudrate_config.

New in version 2.0.4 (Firmware).

request/silent_stepper_brick/<UID>/get_send_timeout_count
Request payload:
 
  • communication_method -- int (has symbols)
Response payload:
 
  • timeout_count -- int

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.

The following symbols are available for this function:

for communication_method:

  • "None" = 0
  • "USB" = 1
  • "SPIStack" = 2
  • "Chibi" = 3
  • "RS485" = 4
  • "WIFI" = 5
  • "Ethernet" = 6
  • "WIFIV2" = 7
request/silent_stepper_brick/<UID>/set_spitfp_baudrate
Request payload:
 
  • bricklet_port -- string
  • baudrate -- int

Sets the baudrate for a specific Bricklet port ('a' - 'd'). The baudrate can be in the range 400000 to 2000000.

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 request/silent_stepper_brick/<UID>/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 request/silent_stepper_brick/<UID>/set_spitfp_baudrate_config).

Regulatory testing is done with the default baudrate. If CE compatibility or similar is necessary in you applications we recommend to not change the baudrate.

The default baudrate for all ports is 1400000.

request/silent_stepper_brick/<UID>/get_spitfp_baudrate
Request payload:
 
  • bricklet_port -- string
Response payload:
 
  • baudrate -- int

Returns the baudrate for a given Bricklet port, see request/silent_stepper_brick/<UID>/set_spitfp_baudrate.

request/silent_stepper_brick/<UID>/get_spitfp_error_count
Request payload:
 
  • bricklet_port -- string
Response payload:
 
  • error_count_ack_checksum -- int
  • error_count_message_checksum -- int
  • error_count_frame -- int
  • error_count_overflow -- int

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.

request/silent_stepper_brick/<UID>/enable_status_led

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.

request/silent_stepper_brick/<UID>/disable_status_led

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.

request/silent_stepper_brick/<UID>/is_status_led_enabled
Response payload:
 
  • enabled -- bool

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

request/silent_stepper_brick/<UID>/get_protocol1_bricklet_name
Request payload:
 
  • port -- string
Response payload:
 
  • protocol_version -- int
  • firmware_version -- [int,int,int]
  • name -- string

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.

request/silent_stepper_brick/<UID>/get_chip_temperature
Response payload:
 
  • temperature -- int

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.

request/silent_stepper_brick/<UID>/reset

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!

request/silent_stepper_brick/<UID>/get_identity
Response payload:
 
  • uid -- string
  • connected_uid -- string
  • position -- string
  • hardware_version -- [int,int,int]
  • firmware_version -- [int,int,int]
  • device_identifier -- int (has symbols)
  • _display_name -- string

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 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 Silent Stepper's name in a human readable form.

Callback Configuration Functions

request/silent_stepper_brick/<UID>/set_minimum_voltage
Request payload:
 
  • voltage -- int

Sets the minimum voltage in mV, below which the register/silent_stepper_brick/<UID>/under_voltage callback is triggered. The minimum possible value that works with the Silent Stepper Brick is 8V. You can use this function to detect the discharge of a battery that is used to drive the stepper motor. If you have a fixed power supply, you likely do not need this functionality.

The default value is 8V.

request/silent_stepper_brick/<UID>/get_minimum_voltage
Response payload:
 
  • voltage -- int

Returns the minimum voltage as set by request/silent_stepper_brick/<UID>/set_minimum_voltage.

request/silent_stepper_brick/<UID>/set_all_data_period
Request payload:
 
  • period -- int

Sets the period in ms with which the register/silent_stepper_brick/<UID>/all_data callback is triggered periodically. A value of 0 turns the callback off.

request/silent_stepper_brick/<UID>/get_all_data_period
Response payload:
 
  • period -- int

Returns the period as set by request/silent_stepper_brick/<UID>/set_all_data_period.

Callbacks

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/silent_stepper_brick/<UID>/under_voltage
Request payload:
 
  • register -- bool
Response payload:
 
  • voltage -- int

A callback can be registered for this event by publishing to the .../register/silent_stepper_brick/<UID>/under_voltage[/<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/silent_stepper_brick/<UID>/under_voltage[/<SUFFIX>] topic for each registered suffix.

This callback is triggered when the input voltage drops below the value set by request/silent_stepper_brick/<UID>/set_minimum_voltage. The callback payload is the current voltage given in mV.

register/silent_stepper_brick/<UID>/position_reached
Request payload:
 
  • register -- bool
Response payload:
 
  • position -- int

A callback can be registered for this event by publishing to the .../register/silent_stepper_brick/<UID>/position_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/silent_stepper_brick/<UID>/position_reached[/<SUFFIX>] topic for each registered suffix.

This callback is triggered when a position set by request/silent_stepper_brick/<UID>/set_steps or request/silent_stepper_brick/<UID>/set_target_position is reached.

Note

Since we can't get any feedback from the stepper motor, this only works if the acceleration (see request/silent_stepper_brick/<UID>/set_speed_ramping) 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/silent_stepper_brick/<UID>/all_data
Request payload:
 
  • register -- bool
Response payload:
 
  • current_velocity -- int
  • current_position -- int
  • remaining_steps -- int
  • stack_voltage -- int
  • external_voltage -- int
  • current_consumption -- int

A callback can be registered for this event by publishing to the .../register/silent_stepper_brick/<UID>/all_data[/<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/silent_stepper_brick/<UID>/all_data[/<SUFFIX>] topic for each registered suffix.

This callback is triggered periodically with the period that is set by request/silent_stepper_brick/<UID>/set_all_data_period. The callback payload members are: the current velocity, the current position, the remaining steps, the stack voltage, the external voltage and the current consumption of the stepper motor.

register/silent_stepper_brick/<UID>/new_state
Request payload:
 
  • register -- bool
Response payload:
 
  • state_new -- int (has symbols)
  • state_previous -- int (has symbols)

A callback can be registered for this event by publishing to the .../register/silent_stepper_brick/<UID>/new_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/silent_stepper_brick/<UID>/new_state[/<SUFFIX>] topic for each registered suffix.

This callback is triggered whenever the Silent Stepper Brick enters a new state. It returns the new state as well as the previous state.

The following symbols are available for this function:

for state_new:

  • "Stop" = 1
  • "Acceleration" = 2
  • "Run" = 3
  • "Deacceleration" = 4
  • "DirectionChangeToForward" = 5
  • "DirectionChangeToBackward" = 6