When To Run Heater Pid Auto Tune
May 05, 2019 Get the current PID settings using the M503command. Your printer will return the current PID settings for the heatbed. Run the M303 E-1 S60 C8 command and wait for the process to finish. The message “PID Autotune start” will appear in the terminal. Your heatbed will start to gradually heat and get new readings. 12v heater carts measure 3-4 ohms and 24v carts measure 12-14 ohms. I did an online chat with Lukas and he is going to send me the 24v carts (I had ordered two complete MK3 hotend assemblies). So if your PID autotune fails with 'temp too high' measure the resistance of your heater carts to make sure you didn't accidentally get a 12v cart. Feb 15, 2017 A basic tutorial on how to perform a 'PID Tuning' on the Prusa Mk2 using Pronterface. Advanced Tuning: ESTEPS calibration and PID Control for your Tevo Tornado 3D. Auto PID Tuning.
This document provides a list of steps to help confirm the pinsettings in the Klipper printer.cfg file. It is a good idea to runthrough these steps after following the steps in theinstallation document.
During this guide, it may be necessary to make changes to the Klipperconfig file. Be sure to issue a RESTART command after every change tothe config file to ensure that the change takes effect (type 'restart'in the Octoprint terminal tab and then click 'Send'). It's also a goodidea to issue a STATUS command after every RESTART to verify that theconfig file is successfully loaded.
After searching over internet I found something about PID autotune, I runned 'M303 P0 S235 X0', after this the graphs looks much more stable. Those swings in the temp can run to a 'heater decoupled' error? PID (Proportional Integral Derivative) is the control algorithm the printers use for holding temperature. The parameters for this algorithm control how fast the printer reaches the set temperature and how well it holds that temperature once it gets there. Fortunately, the printer has an automatic way of tuning. Getting Started. Welcome to the TH3D P.I.D. Auto Tuning Guide! This will take you through the steps to P.I.D. Tune your printers hotend. If you have the new Unified Firmware you can go to Control Temperature PID Autotune Then set to 240 if you have a stock hotend and 250 if. Jan 17, 2012 You can tune again at a higher setpoint after confirming that tuning won’t cause the temperature to go too high. There is probably a time limit on the auto tune function, so very slow processes may not tune. Check the PID settings prior to and after tuning. If they do not change, the auto tuning process failed for one reason or another.
Verify temperature
Start by verifying that temperatures are being properly reported.Navigate to the Octoprint temperature tab.
Verify that the temperature of the nozzle and bed (if applicable) arepresent and not increasing. If it is increasing, remove power from theprinter. If the temperatures are not accurate, review the'sensor_type' and 'sensor_pin' settings for the nozzle and/or bed.
Verify M112
Navigate to the Octoprint terminal tab and issue an M112 command inthe terminal box. This command requests Klipper to go into a'shutdown' state. It will cause Octoprint to disconnect from Klipper -navigate to the Connection area and click on 'Connect' to causeOctoprint to reconnect. Then navigate to the Octoprint temperature taband verify that temperatures continue to update and the temperaturesare not increasing. If temperatures are increasing, remove power fromthe printer.
The M112 command causes Klipper to go into a 'shutdown' state. Toclear this state, issue a FIRMWARE_RESTART command in the Octoprintterminal tab.
Verify heaters
Navigate to the Octoprint temperature tab and type in 50 followed byenter in the 'Tool' temperature box. The extruder temperature in thegraph should start to increase (within about 30 seconds or so). Thengo to the 'Tool' temperature drop-down box and select 'Off'. Afterseveral minutes the temperature should start to return to its initialroom temperature value. If the temperature does not increase thenverify the 'heater_pin' setting in the config.
If the printer has a heated bed then perform the above test again withthe bed.
Verify stepper motor enable pin
Verify that all of the printer axes can manually move freely (thestepper motors are disabled). If not, issue an M84 command to disablethe motors. If any of the axes still can not move freely, then verifythe stepper 'enable_pin' configuration for the given axis. On mostcommodity stepper motor drivers, the motor enable pin is 'active low'and therefore the enable pin should have a '!' before the pin (forexample, 'enable_pin: !ar38').
Verify endstops
Manually move all the printer axes so that none of them are in contactwith an endstop. Send a QUERY_ENDSTOPS command via the Octoprintterminal tab. It should respond with the current state of all of theconfigured endstops and they should all report a state of 'open'. Foreach of the endstops, rerun the QUERY_ENDSTOPS command while manuallytriggering the endstop. The QUERY_ENDSTOPS command should report theendstop as 'TRIGGERED'.
If the endstop appears inverted (it reports 'open' when triggered andvice-versa) then add a '!' to the pin definition (for example,'endstop_pin: ^!ar3'), or remove the '!' if there is already onepresent.
If the endstop does not change at all then it generally indicates thatthe endstop is connected to a different pin. However, it may alsorequire a change to the pullup setting of the pin (the '^' at thestart of the endstop_pin name - most printers will use a pullupresistor and the '^' should be present).
Verify stepper motors
Use the STEPPER_BUZZ command to verify the connectivity of eachstepper motor. Start by manually positioning the given axis to amidway point and then run STEPPER_BUZZ STEPPER=stepper_x. TheSTEPPER_BUZZ command will cause the given stepper to move onemillimeter in a positive direction and then it will return to itsstarting position. (If the endstop is defined at position_endstop=0then at the start of each movement the stepper will move away from theendstop.) It will perform this oscillation ten times.
If the stepper does not move at all, then verify the 'enable_pin' and'step_pin' settings for the stepper. If the stepper motor moves butdoes not return to its original position then verify the 'dir_pin'setting. If the stepper motor oscillates in an incorrect direction,then it generally indicates that the 'dir_pin' for the axis needs tobe inverted. This is done by adding a '!' to the 'dir_pin' in theprinter config file (or removing it if one is already there). If themotor moves significantly more or significantly less than onemillimeter then verify the 'step_distance' setting.
Run the above test for each stepper motor defined in the configfile. (Set the STEPPER parameter of the STEPPER_BUZZ command to thename of the config section that is to be tested.) If there is nofilament in the extruder then one can use STEPPER_BUZZ to verify theextruder motor connectivity (use STEPPER=extruder). Otherwise, it'sbest to test the extruder motor separately (see the next section).
After verifying all endstops and verifying all stepper motors thehoming mechanism should be tested. Issue a G28 command to home allaxes. Remove power from the printer if it does not home properly.Rerun the endstop and stepper motor verification steps if necessary.
Verify extruder motor
To test the extruder motor it will be necessary to heat the extruderto a printing temperature. Navigate to the Octoprint temperature taband select a target temperature from the temperature drop-down box (ormanually enter an appropriate temperature). Wait for the printer toreach the desired temperature. Then navigate to the Octoprint controltab and click the 'Extrude' button. Verify that the extruder motorturns in the correct direction. If it does not, see thetroubleshooting tips in the previous section to confirm the'enable_pin', 'step_pin', and 'dir_pin' settings for the extruder.
Calibrate PID settings
Klipper supportsPID control for theextruder and bed heaters. In order to use this control mechanism it isnecessary to calibrate the PID settings on each printer. (PID settingsfound in other firmwares or in the example configuration files oftenwork poorly.)
To calibrate the extruder, navigate to the OctoPrint terminal tab andrun the PID_CALIBRATE command. For example: PID_CALIBRATE HEATER=extruder TARGET=170
At the completion of the tuning test run SAVE_CONFIG to update theprinter.cfg file the new PID settings.
If the printer has a heated bed and it supports being driven by PWM(Pulse Width Modulation) then it is recommended to use PID control forthe bed. (When the bed heater is controlled using the PID algorithm itmay turn on and off ten times a second, which may not be suitable forheaters using a mechanical switch.) A typical bed PID calibrationcommand is: PID_CALIBRATE HEATER=heater_bed TARGET=60
Next steps
This guide is intended to help with basic verification of pin settingsin the Klipper configuration file. Be sure to read thebed leveling guide. Also see the Slicersdocument for information on configuring a slicer with Klipper.
After one has verified that basic printing works, it is a good idea toconsider calibrating pressure advance.
It may be necessary to perform other types of detailed printercalibration - a number of guides are available online to help withthis (for example, do a web search for '3d printer calibration').
How PID Autotuning Works
To use PID autotuning, configure and deploy one of the PID autotuner blocks, Closed-Loop PID Autotuner or Open-Loop PID Autotuner.
Autotuning Process
The PID autotuner blocks work by performing a frequency-response estimation experiment. The blocks inject test signals into your plant and tune PID gains based on an estimated frequency response.
The following schematic diagram illustrates generally how a PID autotuner block fits into a control system.
Until the autotuning process begins, the autotuner block relays the control signal directly from u to the plant input at u+Δu. In that state, the module has no effect on the performance of your system.
When the autotuning process begins, the block injects a test signal at u out to collect plant input-output data and estimate frequency response in real time.
If you use the Open-Loop PID Autotuner block, the block opens the feedback loop between u and u+Δu for the duration of the estimation experiment. It injects into u+Δu a superposition of sinusoidal signals at frequencies [1/3, 1, 3, 10]ωc, where ωc is your specified target bandwidth for tuning. For nonintegrating plants, the block can also inject a step signal to estimate the plant DC gain. All test signals are injected on top of the nominal plant input, which is the value of the signal at u when the experiment begins.
If you use the Closed-Loop PID Autotuner block, the plant remains under control of the PID controller with its current gains during the experiment. Closed-loop tuning uses sinusoidal test signals at the frequencies [1/10,1/3, 1, 3, 10]ωc.
When the experiment ends, the block uses the estimated frequency response to compute PID gains. The tuning algorithm aims to balance performance and robustness while achieving the control bandwidth and phase margin that you specify. You can configure logic to transfer the tuned gains from the block to your PID controller, allowing you to validate closed-loop performance in real time.
Workflow for PID Autotuning
The following steps provide a general overview of the workflow for PID autotuning.
Incorporate a PID autotuner block into your system, as shown in the schematic diagram.
Configure the start/stop signal that controls when the tuning experiment begins and ends. You can use this signal to initiate the PID autotuning process at any time. When you stop the experiment, the block returns tuned PID gains.
Specify controller parameters such as controller type and the target bandwidth for tuning.
Configure experiment parameters such as the amplitudes of the perturbations injected during the frequency-response experiment.
Start the autotuning process using the start/stop signal, and allow it to run long enough to complete the frequency-response estimation experiment.
Stop the autotuning process. When the experiment stops, the autotuner computes and returns tuned PID gains.
Transfer the tuned gains from the block to your PID controller. You can then validate the performance of the tuned controller in Simulink® or in real time.
For detailed information on performing each of these steps, see:
See Also
Closed-Loop PID AutotunerOpen-Loop PID Autotuner