What is the influence of a lower BAUDrate?
I am using a BAUDrate of 115200 since I cannot make a connection to my printer with the advised 250000 rate. Are there any downsides or limits I reach earlier given by the lower BAUDrate?
Are you experiencing any issues that you suspect could be related to the baud rate, or are you just asking in general? :)
Baud rate for 3d printers has diminishing return on speed. Your printer can only go so fast. The computer sending the data goes a lot of waiting for your printer to catch up. At 115200 is so fast going above that isn't going to make a great deal of difference unless your printer is super fast.
Baud rate is the rate at which information is transferred in a communication channel, given as a number of bits per second (bps). So a baud rate of 250000 is capable of transferring a maximum of 250000 bits per second (31250 bytes/s). When working with serial ports, both ends of the communication line will have to "talk" with the same speed - the same baud rate - to understand each other.
So when using a baud rate of 11520 you will theoretically be limited to transfer data with about half the speed of 25000. If you are transferring large amounts of data, this might be a limiting factor for your application, but if you are not pushing the limits of your serial port, it probably won't matter at all.
@darthpixel, I think you bring up some good points on the effect of low baud rate, though! :)
So this depends mainly on instructions/time. ist there a general rule of thumb, lets say, 'if your mordel is with lots of directional changes, you can only go to speed xx mm/s', or single cases which have been documented? (I'd also be interested in the downvote reasons, - this is an excellent answer)
I don't think you're likely to lower the baud rate to the point where it's slower than the actual machine. Lower baud rates can be a good thing if there's a lot of noise in the signal, such as can happen with cheap cables. It's like talking more slowly to help someone understand you. I prefer to simply use the SD card on my printer and take my PC out of the equation.
@kamuro, on some delta printers you will notice a significant lag if you try to navigate the menus while the printer is doing calculation intensive moves, in my case due to a limited CPU. :) John, the increased S/N-ratio is very interesting! Thanks for sharing. I also stopped printing from USB as you don't need additional variables with 3D printers at the moment.. :)
Thanks for the insight. Delta printers and sloggish LCD response is a known issue with non-32bit Arduino processors. Quintessentially I take that I don't need to worry about the lower BAUDrate if I stay under 200mm/s and super complicated models I guess ;)
hey guys - delta calculations and lag of LCD has nothing to low baudrate I suppose, hasn't it? It's a result of managing everything by small cpu. Or - more precisely - it's a result of slow cpu and wrong (or lack of) interrupts processing I would say.
@darthpixel, that is true, although some might suspect it is related if one does not know what baud rate is! ;-)
@kamuro, I doubt you will ever have to worry about the baud rate if it just is related to streaming gcode over USB: the calculations for moving the printhead are performed by the printers hardware and not your computer (the gcode is interpreted differently by each individual printer/firmware)!
...and that's why we have to choose a firmware for which the gcode will be generated
@TormodHaugene: I know, it's only for transmitting the gcode. But if we never need to worry about it, why was a non-standard BAUDrate chosen to begin with and not the standard 115200?
@kamuro, that is a good question. Apparently you can squeeze out baud 2000000 from 16MHz Arduinos (note the hack in the last post), although the reference states a max of 115200. On the other hand, baud 250000 is apparently used in the DMX, which there even is a external Arduino library for.