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Common Uses with Examples

Kenneth MacCallum michael ganzert
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Running Vanilla FW on Nucleo446

The SFDQ firmware will run on an ST Nucleo446 board with no modifications.

Steps

  • Hook a jumper wire from the CN5.RX to pin CN10.21
  • Hook a jumper wire from the CN5.TX to CN10.33
  • Ensure CN2 jumpers are in place
  • Connect USB cable to PC
  • Program with ST-LINK software or other
  • Start the SFDQ Java app and connect as described in the following section.

Nucleo UART wiring

All of the following examples assume a vanilla SFDQ PCB which is being controlled by the Java application.

Connecting to a SFDQ

The first thing to do with the software is to connect to the SFDQ PCB. This is accomplished with either the ALIAS script command or the ALIASFIRST command. These script commands assign an alias to a particular SFDQ. An alias is a convenient name to identify the board with in your script.

Once the SFDQ is aliased, you will see the telemetry table updating.

Thermal Control with a Heater Resistor

This is useful if you want to control the temperature of something by attaching a power resistor. The resistor will be driven by a high power output and the temperature will be sensed using an NTC thermistor.

Steps

  • mount a 100R power resistor to a small aluminum block
  • wire the power resistor from CN106.3 to CN106.4
  • Make sure the VIN to VHS jumpers are installed
  • glue on a 10k NTC thermistor. You will need to know the thermsitor's beta value.
  • Wire the thermistor from CN113.2 (ADC15) to CN113.4 (ground)
  • hook a 10k reference resistor ifrom CN113.2 to CN113.1 (3V3).
  • power the SDFQ with 12V

Script Commands

//Closed loop thermal feedback example
//Configure thermistor sensing
GPIOPIN sfdq1 C5 0 //set pin as ADC input
ADC sfdq1 15 1.0 0.0 0.0 //setup adc channel
THERMISTORBETA sfdq1 0 15 3380.0 25.0 //setup thermistor to ADC channel 15 and beta of 3380
//now setup feedback
FEEDBACK sfdq1 0 2 0 1 0 false //setup feedback channel 0
FB_IN_LIMITS sfdq1 0 0.0 50.0 //setup input temperature limits to 5C to 50C
FB_OUT_LIMITS sfdq1 0 0.0 1.0 //setup output limits
FB_PID sfdq1 0 1.0 0.1 0.0 //this is a guess at the PID coefficients
TRAJECTORYNOW sfdq1 0 37.0 //set a feedback setpoint of 37C

Stepper Motor Control

This will setup a motor to position control with angle. Until the configuration is good, this can easily brown out.

Steps

  • Connect stepper motor to high power outputs 0-3
  • connect external power brick, or power supply through screw terminals
  • Make sure you have some bulk capacitance on the Vhs to GND - say 1000uF or more.

Script Commands

FEEDBACK SFDQ1 0 06 0 05 0 false //enable feedback controller in open-loop mode and stepper module as its output
STEPPER_PWM SFDQ1 0 1E-3 0.193 2 //enable stepper channel 0
FB_OUT_LIMITS SFDQ1 0 0 1 //allow output from 0 to 1 metre
FB_IN_LIMITS SFDQ1 0 0 1 //same input range
FB_PROP SFDQ1 0 1 //gain of one so the feedback controller will just pass the trajectory through

GRAPHTRAJ SFDQ1 0 "Trajectory" 1 //graph the trajectory
GRAPHSTEPPER SFDQ1 0 "" 0 1 //graph the stepper pos.

TRAJLIN SFDQ1 0 1 10 //now go linearly from 0 to 1 over 10 seconds
TRAJLIN SFDQ1 0 0.1 10 //and back again
TRAJECTORYGO //and GO!

Brushless Motor with Quadrature Encoder

Steps

  • Connect Encoder A,B and Z signals to pins A6, A7 and B0
  • Connect motor widings A, B, C to high power outputs 0, 1 and 2.

Script Commands

BAUD sfdq1 1500000 100 //increase baud rate to 1.5 Mbps
GPIOPIN sfdq1 A6 6 //Encoder A channel
GPIOPIN sfdq1 A7 6 //Encoder B channel
GPIOPIN sfdq1 B0 6 //Encoder Z channel
REGCONFIG sfdq1 20 2 0 0x44 //HW Encoder config register. Will publish to stream 4
REGCONFIG sfdq1 20 2 1 0 //HW Encoder offset register
REGCONFIG sfdq1 20 2 2 18e-3 //HW Encoder scale register. Will now output in degrees (0 to 360)
REGCONFIG sfdq1 20 2 3 20000 //HW Encoder counts per rev register
STREAM sfdq1 4 0x0a 0 0.002 //setup stream for encoder. 2ms sample time

FEEDBACK sfdq1 0 0x0a 4 03 0 false //enable feedback channel with input from stream 4 and output to brushless motor module
FB_IN_LIMITS sfdq1 0 NaN NaN //don't bother with input limits
FB_OUT_LIMITS sfdq1 0 -0.3 0.3 //limit output drive voltage to 30% of rail
FB_UNITS sfdq1 0 1 //use degrees for computation units. This enables circular math

FB_PID sfdq1 0 -0.01 -0.2 0.00000000 //configure a PI controller
BRUSHLESS sfdq1 A5 A4 A3 1 -15 0.5 //enable motor. Hall sensor inputs on pins A5, A4, A3
TRAJECTORYNOW sfdq1 0 170 //now go to 170 degrees

GRAPHSTREAM sfdq1 4 "Encoder" 1 //plot encoder position (angle in degrees)

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