Easier to use Software

fcwilt

That's an interesting proposition.

Using signal busses has the potential of significantly reducing the writing in 3D printers.

I don't think the concept is flawed - just, perhaps, the current firmware which handles the CAN bus.

While my speculation is just that, speculation, it would help to explain why the current firmware (3.2.2) works fine on non-CAN based systems but seems to have problems, as reported by @deckingman, with regards to print quality on CAN based systems.

Frederick

zapta

@fcwilt, it may be tricky to control steppers that need to coordinated but sit on different bus nodes. Would be interesting to hear from dc42@ what the challenges are and if the introduction of a bus degrades degrades significantly the time shift and jitter between the steppers.

The good news is that the movement control is done in open loop and can be planned ahead such that each node just need to perform the plan assigned to it with perfect timing relative to the system's time ticks.

Wireless earplugs have a similar challenge, they need to provide perfect phase matching through two different wireless nodes.

DaBit

The CAN bus was made for stuff like this. There is only a delay in the transmission, and unlike many other serial physical layers that delay is fixed and known. So it is fairly trivial to synchronise a clock over all the CAN-connected boards, down to microsecond level. Once we have a synchronised clock, we have synchronised motion.

I cannot look in the head of the developers, but I am fairly certain that clock synchronisation was the first thing implemented and thoroughly tested since it is so vital.

dc42

@deckingman said in Easier to use Software:

Here are some of pics of a little case I just printed using a simple single input hot end and with pressure advance disabled. It's bloody awful - like the first print ever produced on a crap machine by a rank amateur.

You've declined my suggestion of starting a new thread about this, so I don't know whether you are serious about wanting us to help resolve this. But if you are, then this is what I suggest:

You haven't told us what the perimeter print speed was, or the filament, or the hot end temperature; but the bad corners look to me like the filament taking shortcuts due to printing over-temperature or with poor print cooling, and possibly too fast. Maybe worth printing a temperature tower?
If you install firmware 3.3beta1 then the improved diagnostics in that release will tell us precisely whether the synchronisation of moves over the CAN bus has contributed to the poor print quality.
Leave pressure advance and DAA disabled until we have yout machine printing reasonably without them. Then we can look at the effect of enabling them.

droftarts

@JayJay said in Easier to use Software:

I have (and continue to have) issues if I install RRF3 on my Duet-2 board (but not with RRF2) and have niggly issues on my Duet-3 mini 5+ with RRF3, ... and i just stopped using my 6HC board as its a complete waste of time.

I can’t see any obvious threads from you reporting problems. If there are, please link them, or please start a thread and we’ll try and get any issues sorted out. This may involve posting your config files for each firmware version, though, so we have at least a baseline to work from.

Ian