[3.5.0-beta.3] The engine brakes do not engage.

[dc42]

@Aitor

1. What firmware.versions are you running on each board?

2. Does the X axis fall just a little, or all the way to the bottom?

[Aitor]

Hello @dc42,

In reference to the first point:

M115 B0
FIRMWARE_NAME: RepRapFirmware for Duet 3 MB6HC FIRMWARE_VERSION: 3.5.0-beta.3 ELECTRONICS: Duet 3 MB6HC v1.02 or later FIRMWARE_DATE: 2023-04-14 11:28:15

M115 B1
Duet EXP3HC rev 1.02 or later firmware version 3.5.0-beta.3 (2023-04-13 18:42:24)

M115 B2
Duet EXP3HC rev 1.02 or later firmware version 3.5.0-beta.3 (2023-04-13 18:42:24)

In reference to the second point:

My Z-axis manages both the Y-axis and the X-axis, meaning that the bed remains stationary and does not move. The complete kinematics are based on spindles. For the Z-axis, all four motors are equipped with brakes to prevent them from falling. Normally, they do not completely collapse, but they may tilt towards the heavier side depending on the position of the Y-axis, which disrupts the linearity of the Z-axis.

If you have any additional questions, please feel free to reach out to me. Furthermore, if you require any videos or photos, I would be glad to provide them privately.

Best regards,
Aitor

[dc42]

@Aitor please provide your config.g file.

Regarding the brakes activating at the end of the first layer, please use M122 just before and just after this happens, to check whether the minimum reported VIN voltage drops appreciably at that time.

Please provide the GCode file that leads to this behaviour.

[Aitor]

Hello @dc42,

I apologize for the delay, this printer has been inaccessible and only today I've been able to have it at my disposal. Next, I provide you with my config.g . If you notice anything strange or incorrect, please do not hesitate to tell me. As soon as I have the printer operational, I will carry out the rest of the tests you have requested.

On the other hand, in an initial test I installed version beta4 and M84 still does not activate the motor brakes. The emergency stop, both from the PanelDue and the WebControl interface, also do not activate the motor brake in time.

Best regards,
Aitor

[Dutchprinting]

Hi Guys, @Aitor @dc42

Same here... Motor brakes do not engage when using M18 or M84. It seems like when you plug the power-cord in, the brakes get the 24V.

That is pretty dangerous in my set up as my Z-axis weighs around 350kg...

Also the M569.7 (configure brakes) does not support 2 brakes. so M569.7 C"out0" works fine, but M569.7 C"out0+out1" does not.
Also putting them in seperate M569.7 commands does not work.

The DWC, 1HCL expansion boards and MB6CH are on v3.4.6

Looking forward to a reply!

[jay_s_uk]

@Dutchprinting try 3.5 beta 4. There has been a lot of improvements to 1HCL in that version

[dc42]

@Dutchprinting why would you have two brakes on a single motor?

[Dutchprinting]

@dc42 Bc the brake on the motor is 4Nm, turns out it is too weak. Now i've put a 9Nm brake in between the motor and the gearbox. As the brake is embedded in the motor body i cannot remove it. I think i will just put boths brakes together in a connector on 1HCL out0.

@jay_s_uk After updating to 3.5 beta 4 i have the following problem :
it looks like the brakes dont get enough power, some boards do the tuning manuever well and some error and fail, i tried it with only the motor brake and the motor brake + new brake. The one's that do work engange when M18 is send, so thats progress...
i think my best option is to switch back to v3.4.6 and try with the double brakes.

Here is my config: (some parameters are still off due to testing)

M569.1 P50.0 T2 S200 C1000 R100 I0 ; Configure the 1HCL board
M569.1 P123.0 T2 S200 C1000 R30 I2000 ; Configure the 1HCL board
M569.1 P52.0 T2 S200 C1000 R30 I2000 ; Configure the 1HCL board
M569.1 P53.0 T2 S200 C1000 R30 I2000 ; Configure the 1HCL board
M569.1 P54.0 T2 S200 C1000 R30 I2000 ; Configure the 1HCL board

M569.7 P50.0 C"out0" S1 ; control the brake
M569.7 P123.0 C"out1" S1000 ; control the brake
M569.7 P52.0 C"out1" S200 ; control the brake
M569.7 P53.0 C"out1" S1000 ; control the brake
M569.7 P54.0 C"out0" S200 ; control the brake

M569 P50.0 S1 D4 ; physical drive 50.0 goes forwards
M569 P123.0 S1 D4 ; physical drive 51.0 goes forwards
M569 P52.0 S0 D4 ; physical drive 52.0 goes forwards
M569 P53.0 S0 D4 ; physical drive 53.0 goes forwards
M569 P54.0 S0 D4 ; physical drive 54.0 goes forwards
M569 P55.0 S1 D4 ; physical drive 55.0 goes forwards

M584 X52.0 Y50.0:54.0 Z123.0:53.0 E55.0 ; set drive mapping / :54.0
M92 X25.64 Y25.64 Z25.64 E25.64 ; set steps per mm (vention 125mm per full rotation / 200 steps = 1.6)
M350 X32 Y32 Z32 I0 ; Set microstepping mode
M566 X900.00 Y900.00 Z100.00 E120.00 ; set maximum instantaneous speed changes (mm/min)
M203 X8000.00 Y8000.00 Z4000.00 E100.00 ; set maximum speeds (mm/min)
M201 X300.00 Y300.00 Z300.00 E250.00 ; set accelerations (mm/s^2)
M906 X6000 Y6000 Z6000 E800 I100 ; set motor currents (mA) and motor idle factor in per cent
M917 X10 Y10 Z100 ;0.71 ; set closed loop axes to have current of 10 percent
M84 S1 ; Set idle timeout in seconds

---

And for a reference, this is the printer i'm building:

[Dutchprinting]

@dc42 Unfortunately i cannot edit the post above. I have tested alot more and have things sort of working now.

i'm on 3.5 beta 4. The only thing is that the brakes do not engage when M18 of M84 is send.
i can rotate the motor by hand when M18 is send. When i send M17 the motor enables and holds its torque ofcourse.

With the weight of the gantry in mind i could move it to a sort of 'stand' to rest on and then turn the power off.
The brakes will also save me in the case of a power failure.

The thing is... after a power failure, When i power the system back up, the motors AND brakes are not engaged. So the gantry drops down.

So my question is... is there a way to disable out0 at startup, and only enable when the motor is enabled? (1HCL)

@jay_s_uk i'm guessing DC knows best but maybe you can chip in?

[dc42]

@Dutchprinting have you checked that all boards in your system are running RRF 3.5.0-beta.4 ?

[Dutchprinting]

@dc42 Yes, all of them run the the 3.5 beta 4. i double checked with M115. Also the DWC and mainboard 6ch are on 3.5 beta 4

[Dutchprinting]

@dc42 Quick update, printer is running and printing, the 3,5 beta 4 runs perfectly in open loop mode. Before shutdown i switch to closed-loop (without tuning maneuvre) to engage the brakes and shutdown the system, at startup they also begin in closed loop so the gantry doesnt drop down.

Cant get the Nema34's tuned tho... it gives weird oscilations and sounds with the standard settings. also the tuning maneuvre gives incostistent values and errors.

Would love some help on this topic. bc my printer has small inconsistencies in open-loop and i want to run in closed loop.

Kind regards!

[dc42]

@Dutchprinting said in [3.5.0-beta.3] The engine brakes do not engage.:

Before shutdown i switch to closed-loop (without tuning maneuvre) to engage the brakes and shutdown the system

Are you saying that the brakes work if you shut down in closed loop mode, but not if you shut down in open loop mode?

[Dutchprinting]

@dc42 That is correct. When shutting down in open-loop mode what happens is: (in this order)

1. Power off by hand (unplugging power cord) or emergency stop by DWC
2. motors lose currect (lose their holding torque) and gantry moves down.
3. after a slight delay (0.5sec) brakes engage bc of loss of power and stop the gantry from falling further down.

When the gantry weight was still 250kg's the brakes couldnt stop the downward movement and it continued to fall down.
Now we have 2x 100kg's counterweights and the ''weight'' of the gantry is now 50kg's. So now they can stop it when it falls. But that doesnt happen anymore as long as i do the shutdown procedure.

Startup procedure:

1. At startup it runs the config file wich contains M569 P50.0 S0 D4. (closed-loop without tuning maneuvre so brakes are engaged)
2. after that i manually run a startup macro: M569 P50.0 S0 D0 and run open loop mode.

Shutdown procedure:

1. Run macro wich only contains 5x M569 P50.0 S0 D4. for all the motors (to engage the brakes again)
2. Power off (unplug the cord)

.
NOTE: When updating the boards to new firmware, the motors lose holding torque AND the brakes are dis-engage. wich makes the gantry fall down too. i dont know if its in open-loop or closed loop when starting the update, but i could replicate this if you like.