So, I had the right idea how the axis should work, and after the 7:th combination and switched x & y motor connections I finally found the right settings!
Thank you so much for your patience and great answers to me who´s just starting to understand the in´s & out´s of Duet and reprapfirmware!
I'm still not clear about whether RepRapFirmware can turn the stepper motors off when they've been idle for long enough; in fact I'd prefer the firmware to automatically turn the ATX supply off and on when needed, but I realize that "when needed" is a little complicated given that steppers lose microsteps when powered down and hotends can jam if the heatsink is not cooled when it needs it. So for the moment I have G-code to cool the hot end and then shut down ATX power at the end of a successful print; cancelled prints require the user to shut down by hand.
By default, RRF reduces motor current to 30% of normal when all motors have been idle for 30 seconds. The percentage and the timeout can be adjusted using the M906 command.
You can write a macro file to cool the hot end down and then turn the ATX PSU off.
In a future version of RRF, I intend to add the facility to move all motors slightly to a position that corresponds to how they will power up again. That should reduce the risk of the motors jumping steps when you power off and on.
Some people swear by it (sandblasted glass that is) I'll let you know how I get on. I haven't tried printing on plain glass - it's just that the instructions for my original RRP Mendel recommended Kapton tape and I've become fairly proficient at fitting it, so I've carried on. That's with a 200mm square bed and as the new one is 400mm square, I think I'll need to do something different.
I tried your probe with ground side up and ground side down. The trigger height is different but it works OK for me. Maybe it's the extra thickness (mine is 6mm)??
1. Switch the bed back to bang-bang control, using the B1 parameter in the M307 command.
2. Try connecting the LED strip directly to your power supply instead of to VIN. That avoids the resistance of the leads from the PSU to the Duet causing voltage drop at the Duet when the bed heater turns on.
3. Use a better-regulated power supply (probably in conjunction with (2) above).
4. If your 12V PSU has sufficient extra power capacity. turn up its voltage to 14V, then use a 12V low dropout regulator to provide a better-regulated 12V supply for the LEDs.
5. Use a separate PSU for the LEDs, or a separate PSU for the bed heater.
6. In a future firmware revision I may make the bed heater PWM configurable, then you will be able to turn it up to 70Hz or greater, high enough for the eye not to see.
As others have said, running two "normal" fans from the same PWM fan channel is fine.
The FET user is the PMV40UN2R is rated to ~4A, however that should be derated significantly to take into account the PWM switching losses and to reduce the max temp the FET gets to so 1A should be safe. Given that most fans that would be used for this are <0.2A your configuration should be fine.
Thank you Tony, I knew something didn't feel right about my numbers! Let's hope I can squeak more than 55% efficiency out of that board..
The LattePanda is definitely interesting - I have not yet played with one, the Kickstarter reviews are so-so, so we'll see how it turns out. I do plan on printing a case for a 7 inch LCD/touchscreen. If the dimensions work out correctly I will mount that and the PanelDue drawer style under the printer and be able to slide them out when needed.. more often than not I'm sure with will be accessing the Windows side of the Panda via RDP if it's powerful enough to run simplify.
For KiCAD you need to use at least version 4.0.2. The custom parts are in the distribution on Github, you might need to point your libraries path at that, I thought it was relative within the project but maybe its not.
Adding the ability to trigger a pause using one of the expansion header pins would be useful, we cant replace the erase button though because if invalid firmware is uploaded to a board, erase is required to reset the board so valid firmware can be uploaded via USB.
I read you all and this fully answer my question. I guess 25V shall be fine.
What is a typical pumping voltage when breaking up to 3-4 volts?
I guess it depends on how well the powersupply regulation electronics can sink reverse current and of the stepper inertia and inductance.
We had a problem like this on one of our electronics and we had to change the regulator to cope with it.
As Tim says, the limitation is the stepper drivers, which are rated at 30V when the motors are powered, and motors pump energy into the supply rail when they are decelerating. The other components are rated at 35V or more. A future revision of the firmware will disable the drivers if the bus voltage exceeds about 29V.
Is there a reason why you want to use more than 25V?
The remote power on/off facility on the Meanwell PSUs appears to be compatible with the implementation on ATX PSUs, so it ought to be work with the Duet WiFi PS_ON output.
For the lower current connections such as PT100, you can use a JST style 2.54 connector pin. There are different types from 2 pins to 20 pins and they have a locking feature to prevent accidental demates. There is no point in routing the PT100 and hot end on same connector unless you split the hot end into multiple pins to reduce the current through each pin. If the connector is rated for high current, it would be large, and vice versa for smaller connector. You always way to keep the high current connection on a different connector.
Phil 51C at 2A, with your lower ambient temp and airflow does not sound unreasonable compared to our results. That's for doing the additional tests, it will be interesting to see in 6 months time when your ambient temp is slightly different!