parameters

WARNING: this information has been written in 2021, when pypilot version was 0.24 and Openplotter was 2.0. In 2023 these versions have by far been superceded and information in this chapter is most likely to be partly obsolete. Work in progress will be documented in the Workbook Release Notes.

The following list of parameters are limited to those that are saved in pypilot.conf.

ap.mode	default: compass; screen: Control
	Chosen autopilot mode (e.g. compass, gpc, wind, true wind); apparently this choice survives a restart.

ap.pilot	default: basic; screen: Gain screen
	Current choice of autopilot algorithm.

ap.pilot.*
	These are the gains for the different autopilots. See Gains

Tacking functionality
Basic idea when you hit tack
https://forum.openmarine.net/showthread.php?tid=1469&pid=7184#pid7184:

1. wait tack delay
2. change course to tack angle or opposite wind angle
3. move rudder at tack rate until it hits end of travel, or boat is tack threshold

ap.tack.angle	default: 100; screen: Configuration screen
	Degrees. In wind mode it is automatically determined from current course https://forum.openmarine.net/showthread.php?tid=1469&pid=7184#pid7184

ap.tack.count	default: 0; screen:
	Number of tacks made.

ap.tack.delay	default: 0; screen: Configuration screen
	How many seconds to wait to tack after hitting tack button https://forum.openmarine.net/showthread.php?tid=1469&pid=7184#pid7184

ap.tack.rate	default: 20; screen: Configuration screen
	How quickly to tack. Unit is degrees/sec. https://forum.openmarine.net/showthread.php?tid=1469&pid=7184#pid7184

ap.tack.threshold	default: 50; screen: Configuration screen
	When to revert back to normal filter. Unit is percentage. Typically half the tack angle but adjusting this would be useful to prevent overshoot. https://forum.openmarine.net/showthread.php?tid=1469&pid=7184#pid7184

apb.xte.gain	default: 300; screen: Client
	In GPS mode (when following an APB track), correct the track heading based on the XTE, multiplied by this gain. Example: track is north, but XTE is 0.05 left. Pypilot will steer 000 + 300 * 0.05 = 015 to go back to the track. https://forum.openmarine.net/showthread.php?tid=2078&pid=10805#pid10805

imu.accel.calibration	default: ; screen:

imu.accel.calibration.age	default: - ; screen:

imu.accel.calibration.locked	default: false; screen: Client

imu.accel.calibration.points	default: ; screen:

imu.alignmentQ	default: ; screen:
	This seems to be the result of the Boat is Level action, and it is a vector the points to the sky.

imu.compass.calibration	default: ; screen:

imu.compass.calibration.age	default: - ; screen: Calibration - Compass
	When this resets to 0, you know your compass just calibrated. I check this at the start of a trip, do a semi circle, wait until it resets.

imu.compass.calibration.locked	default: false; screen: Calibration - Compass
	Lock compass calibration, when you don't want any surprises.

imu.gyrobias	default: false; screen:

imu.heading_offset	default: 0; screen: Calibration screen
	When you installed your IMU in your boat, it did not have any reference to where north is. After telling pypilot that "Boat is level", this corrects the compass heading. Tweak it until the compass heading in the pypilot control screen equals the corrected heading read from your boat compass, or, with no current or drift, your COG.

imu.rate	default: 10; screen: Client
	Can be set to 10 or 20; apparently this has to do with update rate from the compass/imu. Unit is Hz: number of updates per second. https://forum.openmarine.net/showthread.php?tid=1849&pid=9756#pid9756

nmea.client	default: ; screen:

The following settings (rudder.*) result from the rudder calibration procedure https://pypilot.org/wiki/doku.php?id=calibration, in case you have a rudder feedback sensor. I'll leave it here because this might become topical with the advent of the 'absolute' pypilot algorithm.

rudder.nonlinearity	default: 0; screen: , EEPROM

rudder.offset	default: 0; screen: , EEPROM

rudder.range	default: 45; screen: Calibration screen, EEPROM

rudder.scale	default: 100; screen: , EEPROM

servo.amp_hours	default: 0; screen: Statistics
	Collective amp hours that the pypilot has used. Can be reset with the button Reset. Could be used for monitoring or optimising pypilot efficiency.

servo.compensate_current	default: false; screen: Client
	No references, does not seem to be used in the code.

servo.compensate_voltage	default: false; screen: Client
	According to the code of servo.py, this compensates the motor speed for fluctuating battery voltage (!).

servo.current.factor	default: 1; screen: Client, EEPROM
	You can fine tune the current reading with this one. Tricky thing to do - use pypilot_scope to plot servo.current, and be very quick reading an amp meter in the power supply line of pypilot while moving the motor; then calculate a factor.

servo.current.offset	default: 0; screen: Client, EEPROM
	See servo.current.factor. Offset, what can I say.

servo.disengage_on_timeout	default: true; screen:
	No references on forum.

servo.faults	default: 0; screen:
	Not visible in any screen, but apparently it counts the servo faults. That's a diagnostic

servo.gain	default: 1; screen: Client, EEPROM
	Effectively an overall gain, although it has to do with the servo speed. It defaults to 1, so changing to 2 or 3 will get much more response. The servo gain was added for extremely fast/slow motors and also a way to change wires. https://forum.openmarine.net/showthread.php?tid=1924&pid=9789#pid9789 https://forum.openmarine.net/showthread.php?tid=2657&pid=14394#pid14394

servo.max_controller_temp	default: 60; screen: Client, EEPROM
	In degrees C, when the NTC measures a temperature higher than this, it shuts down pypilot with an OVERTEMP servo flag. Saved me once, when I fried my H-Bridge.

servo.max_current

default: 7; screen: Configuration screen, EEPROM

If the current used by the motor exceeds the max_current, it will stop the motor and raise a FWD_FAULT or REV_FAULT flag. This also works as a rudimentary end-of-travel stall mechanism. If max_current is set too high, the overcurrent will not trigger if the motor stalls. If too low, it will trigger by mistake. Pypilot temporarily increases this value to get an engine 'unstuck' when it has reached the end of travel. https://forum.openmarine.net/showthread.php?tid=3361&pid=18829#pid18829 https://forum.openmarine.net/showthread.php?tid=2078&pid=19068#pid19068

servo.max_motor_temp	default: 60; screen: Client, EEPROM
	See servo.max_controller_temp.

servo.max_slew_speed	default: 18; screen: Configuration screen, EEPROM
	acceleration ( setting lower will reduce current spikes but also responsiveness, this setting can affect the servo.max_current setting) https://forum.openmarine.net/showthread.php?tid=3361&pid=18829#pid18829

servo.max_slew_slow	default: 28; screen: Configuration screen, EEPROM
	deceleration, see servo.max_slew_speed

servo.period	default: 0.4; screen: Configuration screen
	the minimum time the motor is moving in a certain direction or stopped, reducing will make shorter movements with less reaction time, but increasing will reduce the wear on the motor and avoid as many counter corrections. https://forum.openmarine.net/showthread.php?tid=3361&pid=18829#pid18829

servo.position.{d,i,p}	default: 0.02; screen: Client
	No references found on the forum. From the naming and code in servo.py it can be deduced that it is related to the PID control mechanism that brings the rudder into a certain position. I'll leave it here because this might become topical with the advent of the 'absolute' pypilot algorithm.

servo.speed.max	default: 100; screen: Configuration screen, EEPROM
	the maximum movement speed, usually always 100. If you had a 24 volt system and motor controller and 12 volt motor you could use 50 to avoid burning it out https://forum.openmarine.net/showthread.php?tid=3361&pid=18829#pid18829

servo.speed.min

default: 100; screen: Configuration screen, EEPROM

the minimum continuous speed. This can also generally be set to 100 to get the best performance. As it is reduced the noise of the ram decreases but generally at the expense of power consumption, especially on high friction drives. If this is too low, the efficiency is worse. How much worse depends on the type of motor and drive. For lead screws use 80-100, for more efficient drives like ball screws you can go down to 50. https://forum.openmarine.net/showthread.php?tid=3361&pid=18829#pid18829

servo.use_eeprom

default: true; screen:

Some servo settings, like rudder calibration, slew speeds, max current and a few others are stored on the motor controller's eeprom. This way the motor specific settings are not lost if you upgrade, and if you have two motor controllers and two motors you could use the backup one with different settings. Disables reading the values from the motor controller, if you change it to "False". If you do this and e.g. set the slew values in the config, they will be used and the motor controller will not be read. You might try this if you have trouble with the slew getting reverted. https://forum.openmarine.net/showthread.php?tid=3042&pid=16726#pid16726 https://forum.openmarine.net/showthread.php?tid=2212&pid=11625#pid11625 These eeprom parameters are the following, and they are also marked with EEPROM in the description: servo.max_current, servo.max_controller_temp, servo.max_motor_temp, servo.max_slew_speed, servo.max_slew_slow, servo.sensors.rudder.scale, servo.sensors.rudder.nonlinearity, servo.sensors.rudder.offset, servo.sensors.rudder.range, servo.current.factor, servo.current.offset, servo.voltage.factor, servo.voltage.offset, servo.speed.min, servo.speed.max, servo.gain, servo.clutch_pwm

servo.voltage.factor	default: 1; screen: Client, EEPROM
	This can be used to fine tune the voltage reading in the Statistics screen. If your controller voltage is beyond certain values, you will get a BAD_VOLTAGE server flag and your pypilot will not work. If the voltage is really way off, you have a bad configuration of your voltage divider resistors so you need to go back to the soldering iron.

servo.voltage.offset	default: 0; screen: Client, EEPROM
	See above: servo.voltage.factor

wind.offset	default: 0; screen: Configuration screen
	No references found on the forum.