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.
edit: added a page to the wiki that links to the source files:
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.
Good thing about the psu on!
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!
Will do a total rewire near hotend for more modular handling.
Was very happy with my board. Fixing the SMD mosfet i can probably do, but not a chance with the SAM3XE…
As I wrote before i could take a black/blue as the replacement (#257)
Getting all shaky not being able to print
And I just got the bed calibrated almost perfectly too
I presume you have a single hot end, also with a PT100, and the dual PT100 daughter board. In which case, you have a spareb PT100 channel anyway. Why not connect both the thermistor and the PT100? You will be able to switch between them in firmware.
@ DC42. Yes, that's what I was planning to do.
@All. Thanks for the info and tips guys.
One solution is to feed mains to the PSU via the NO contacts of a relay. Also connect a mains-rated NO push button in parallel with the relay contacts. Connect the relay coil between the PS_ON output of the Duet and either +5V or +12V. Don't forget the flyback diode across the relay coil.
In config.g put command M80 near the start, to turn the relay on. To start the printer, press the push button and hold it until the relay turns on. Then you can use command M81 to turn the printer of. This can be done in your end gcode. Don't forget to put a G4 delay command before it, to allow the hot end fan to cool the hot end down first.
One disadvantage of this approach is that whenever you do a software reset, the printer will turn off.