6HC feed rate control

marlyman

Hi Guys, Im having unbelievable trouble setting the duet 3 6hc up with speed control problems. My config.g has the m203 set to 3500, and the feed rate for move button at 2500. so thats the controls sorted. however g0 command run at 82.5mm/s, g1 commands are running at 50mm/s, homing all command are running at 50mm/sec but the feed rate is set at 30mm/min, my home x is set to run at 1800 but its moving at 30mm/sec. i just ran a toolpath set to 3000mm/min and the speed shot up to 58mm/sec
any ideas?

gloomyandy

I think it would help if you explained a little more about what exactly it is you are doing (so what commands are you issuing and how are you issuing them), what you expect to happen and what exactly happens (so for instance how do you know what speed a move is actually operating at). It would also probably make it easier for folks to help you if you posted your config.g file and a few details of the printer/machine that you are trying to control.

Oh and you stated that...

my home x is set to run at 1800 but its moving at 30mm/sec

Well 1800mm/min (which is the units typically used to set the feedrate of a move) is 30mm/sec so it looks like that is operating as intended.

dc42

@marlyman are you by any chance running a CoreXY machine with CNC or laser mode selected? If so:

G1 moves should always occur at the feed rate you selected in the F parameter, provided that you don't hit the limits implied by M203
G0 moves will run as fast as possible, in line with the NIST specification. [In FDM mode, G0 moves are also controlled by the F parameter.]
M203 on a CoreXY machine specifies the speed for pure X and pure Y moves. The speed for diagonal moves will be lower, because RRF allows for the fact that whereas pure X and pure Y moves share the load equally between the two motors, diagonal moves place more load on one motor than the other.

That said, some of the speeds you report don't look right. Homing moves at 1800mm/min will indeed proceed at 30mm/sec. G1 X or Y moves with F parameter 3000 should give you 50mm/sec unless the M203 limits force a lower speed.

With M203 set to 3500 for both X and Y, G0 moves in the X and Y directions should run at 58.3mm/sec. Diagonal moves will be slower.

marlyman

@gloomyandy @dc42 thank you for your posts. im now in the clear. please mark solved.