Z movement noise issue, for firmware specialist and detectives

Hi guys,

So I've been having a lot of trouble with Hexagon hotend on my Lulzbot TAZ 3. The tool head itself I got to work alright, but there is trobuble in the Z axis movement, after flashing firmware.

I will give you short sequence of events.
Please read it carefully if you want to help since I've been corresponding to a lot of people and lots of stuff are covered-

1. Installed toolhead
2. Flashed firmware for TAZ 5 with hexagon hotend (mistake)
3. Noticed wrong Z heights while printing (squashed prints)
4. Found and flashed proper firmware for TAZ 3 with hexagon hotend
5. Problem appears - [youtu.be]
6. Contacted support and tried all sorts of tweaks -loosening and retightening the screws, leveling X axis on both sides, changing value of Vmax Z from 8 down to 3
7. Flashed stock firmware which showed that motors work fine on it- [youtu.be]

The strangest thing is that the Support went and tested the firmware in question at their workstation on the same machine, and it worked correctly.

Here is one more video of my both motors working simultaneously on that problematic firmware- [youtu.be]
Please note that it gives a lot of speed to motors and I think it overshoots the distance. I keep giving it a 10mm movement and in my opinion it goes a lot more.
That's all I know.

I've been trying for a year now to get this Hexagon hotend of mine to work.
I am not giving up

What firmware are you using? In Marlin you only need to change the thermistor number if you're switching hotends, so everything else should stay the same.

Quote
AlexY
What firmware are you using? In Marlin you only need to change the thermistor number if you're switching hotends, so everything else should stay the same.

Hi,

firmware is Marlin - [devel.lulzbot.com]

I am not sure if thermistor is the only thing that needs changing. Beside maxtemp. they gave me to change some more things. I am not shure what for. Here are the lines they gave me:


"The firmware changes you need to make are going to be found in the file Configuration.h. Find the blocks below in the file and change the values to this:

#define TEMP_SENSOR_0 5
#define TEMP_SENSOR_1 5
#define TEMP_SENSOR_2 0
#define TEMP_SENSOR_BED 7

// When temperature exceeds max temp, your heater will be switched off.
// This feature exists to protect your hotend from overheating accidentally, but *NOT* from thermistor short/failure!
// You should use MINTEMP for thermistor short/failure protection.
#define HEATER_0_MAXTEMP 305
#define HEATER_1_MAXTEMP 250
#define HEATER_2_MAXTEMP 250
#define BED_MAXTEMP 150

You'll need to add an entry to the PID settings section, look for:

// PID settings:
// Comment the following line to disable PID and enable bang-bang.
#define PIDTEMP
#define BANG_MAX 127 // limits current to nozzle while in bang-bang mode; 255=full current
#define PID_MAX 127 // limits current to nozzle while PID is active (see PID_FUNCTIONAL_RANGE below); 255=full current
#ifdef PIDTEMP
//#define PID_DEBUG // Sends debug data to the serial port.
//#define PID_OPENLOOP 1 // Puts PID in open loop. M104/M140 sets the output power from 0 to PID_MAX
#define PID_FUNCTIONAL_RANGE 16 // If the temperature difference between the target temperature and the actual temperature
// is more then PID_FUNCTIONAL_RANGE then the PID will be shut off and the heater will be set to min/max.
#define PID_INTEGRAL_DRIVE_MAX 127 //limit for the integral term should be set under PID_MAX term
#define K1 0.96 //smoothing factor within the PID
#define PID_dT ((16.0 * 8.0)/(F_CPU / 64.0 / 256.0)) //sampling period of the temperature routine
// If you are using a preconfigured hotend then you can use one of the value sets by uncommenting it

and add:

// AO-Hex on 24V
#define DEFAULT_Kp 9.5
#define DEFAULT_Ki 0.63
#define DEFAULT_Kd 37.78 "

Try changing only the max temperature and thermistor number for now; keep the PID settings the same as before and verify that the Z-axis doesn't have problems. Afterwards you can run a PID autotune to get the temperature regulation calibrated.

Also, make sure that your z-axis steps per mm didn't accidentally change during the firmware upgrade.

Edited 1 time(s). Last edit at 09/26/2015 12:27PM by AlexY.

Quote
AlexY
Try changing only the max temperature and thermistor number for now; keep the PID settings the same as before and verify that the Z-axis doesn't have problems. Afterwards you can run a PID autotune to get the temperature regulation calibrated.

Also, make sure that your z-axis steps per mm didn't accidentally change during the firmware upgrade.

Thank you, I will try then to go step by step changing parameters in configuration.h
Do you know anything about the BANG BANG mode in my code above? It apparently limits the current to the nozzle. I've also changed this parameter as they had proposed. Maybe I am getting some surges because of it..

Hey t0bb, can you post the stock firmware that is working great for you?. I don't own a TAZ, but i had Repetier 0.92 on my firmware, and had to move to marlin, and got a similar issue.

I found that Marlin has merged the Max Acceleration from all steppers into a single value shared for them, this cause the Z axis (which requires more steps per unit) to overshoot and spind too fast, causing lot of noise and torque loss.

I had to step down this

#define DEFAULT_ACCELERATION          500    // X, Y, Z and E max acceleration in mm/s^2 for printing moves

to a lower value until i was satisfied with.

Hope this could help you.

EDIT:
P.S.: I don't know if that value can be split into a matrix row, as other values like this

#define DEFAULT_AXIS_STEPS_PER_UNIT   {100.5,100.5,800,800}  // default steps per unit for Ultimaker
#define DEFAULT_MAX_FEEDRATE          {800, 800, 3, 50}    // (mm/sec)
#define DEFAULT_MAX_ACCELERATION      {9000,9000,100,10000}    // X, Y, Z, E maximum start speed for accelerated moves. E default values are good for skeinforge 40+, for older versions raise them a lot.

Edited 1 time(s). Last edit at 09/26/2015 08:47PM by lynspyre.

Quote
lynspyre
Hey t0bb, can you post the stock firmware that is working great for you?. I don't own a TAZ, but i had Repetier 0.92 on my firmware, and had to move to marlin, and got a similar issue.

I found that Marlin has merged the Max Acceleration from all steppers into a single value shared for them, this cause the Z axis (which requires more steps per unit) to overshoot and spind too fast, causing lot of noise and torque loss.

I had to step down this

#define DEFAULT_ACCELERATION          500    // X, Y, Z and E max acceleration in mm/s^2 for printing moves

to a lower value until i was satisfied with.

Hope this could help you.

EDIT:
P.S.: I don't know if that value can be split into a matrix row, as other values like this

#define DEFAULT_AXIS_STEPS_PER_UNIT   {100.5,100.5,800,800}  // default steps per unit for Ultimaker
#define DEFAULT_MAX_FEEDRATE          {800, 800, 3, 50}    // (mm/sec)
#define DEFAULT_MAX_ACCELERATION      {9000,9000,100,10000}    // X, Y, Z, E maximum start speed for accelerated moves. E default values are good for skeinforge 40+, for older versions raise them a lot.

Hi lynspyre,

here is my stock firmware that works fine- [devel.lulzbot.com]
just open configuration.h file with wordpad

here is the troubled firmware in question- [devel.lulzbot.com]
also open configuration.h

What troubles me is that they tested it on the machine same as mine and it worked for them properly. Something happened with my machine while I was on the wrong advanced firmware for TAZ 5 (I am TAZ 3)
But again if something happened it should have made problems for me on the stock firmware later as well.... a bit confusing..

thanks for the insight though !

Edited 1 time(s). Last edit at 09/27/2015 04:34AM by t0bb.

Regarding my Z steps issue-

It seems long ago, when we flashed the wrong firmware (TAZ 5 rather then TAZ 3 I needed), we made some LCD changes and hit "store memory" option
Because of that, it keep the wrong z steps per mm inherited from TAZ 5. And no firmware ever overrode it. I had to manually enter LCD (by accident) and change those values manually to steps per mm which are adequate...

Beware of configuration changes you make!

Quote
t0bb

Hey t0bb, here is a list of thing i've seen on both firmwares

1. First thing i see in both firmwares is Baudrate don't know if that could cause problems, but, as i've read, it's better to use 250000.
2. None of the temps settings are similar or equals.
3. One endstop pullup not defined on working firmware; defined on problematic one.
4. Steppers feedrates not the same.
5. On problematic firmware it has an Y-axis offset set, you have to check it out.
6. Both have EEPROM defined, so when you set the correct Z-steps/mm use M500 to store data to EEPROM, this should solve wrong default steps/mm

That's all i can see you maybe need to check both, other than that, i don't see any disturbances.

Quote
t0bb

Quote
lynspyre
Hey t0bb, can you post the stock firmware that is working great for you?. I don't own a TAZ, but i had Repetier 0.92 on my firmware, and had to move to marlin, and got a similar issue.

I found that Marlin has merged the Max Acceleration from all steppers into a single value shared for them, this cause the Z axis (which requires more steps per unit) to overshoot and spind too fast, causing lot of noise and torque loss.

I had to step down this

#define DEFAULT_ACCELERATION          500    // X, Y, Z and E max acceleration in mm/s^2 for printing moves

to a lower value until i was satisfied with.

Hope this could help you.

EDIT:
P.S.: I don't know if that value can be split into a matrix row, as other values like this

#define DEFAULT_AXIS_STEPS_PER_UNIT   {100.5,100.5,800,800}  // default steps per unit for Ultimaker
#define DEFAULT_MAX_FEEDRATE          {800, 800, 3, 50}    // (mm/sec)
#define DEFAULT_MAX_ACCELERATION      {9000,9000,100,10000}    // X, Y, Z, E maximum start speed for accelerated moves. E default values are good for skeinforge 40+, for older versions raise them a lot.

Hi lynspyre,

here is my stock firmware that works fine- [devel.lulzbot.com]
just open configuration.h file with wordpad

here is the troubled firmware in question- [devel.lulzbot.com]
also open configuration.h

What troubles me is that they tested it on the machine same as mine and it worked for them properly. Something happened with my machine while I was on the wrong advanced firmware for TAZ 5 (I am TAZ 3)
But again if something happened it should have made problems for me on the stock firmware later as well.... a bit confusing..

thanks for the insight though !

try sublime text2, its a file reader, then get the Gcode exstention, or some other text reader that doesnt add invisable characters, it can feck up some programs that read the invasable text as program lines.

on your vid clip (i am a newbie at the mo) is that noise coming from your z motors? if it is theyre welllll out on the power..? just a thought, but..i am a begginer.