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DC42 buffering gcode Host controller development

Posted by D9ve 
DC42 buffering gcode Host controller development
March 16, 2016 02:26PM

What would be the best method to send multiple gcode commands to the duet that help eliminates jitter and utilizes the gcode buffer (I'm developing a custom Host controller)?

The problem I am experiencing and current method:
Currently after every G1 command sent I wait for an "ok." reply from the firmware before sending the next command.

approx 10ms between each character received
approx 150ms between each command sent (depending on distance travelled)

command example: G1 Xn.nnn Yn.nnn Zn.nnn En.nnn:n.nnn:n.nnn:n.nnn S1

I know that there is a gcodeBuffer, although i'm not 100% sure how to use it correctly and am hoping this will eliminate some of the start/stops (stutter) between each new coordinate.

The error I am trying to eliminate the jittering/stuttering between each new line segments/ command sent, ie it seems the printer decelerates and stops (very very briefly) between each command sent ( the repetitive force causes the printer to shunt a little across the table, but not step out). This error is very prominent on curve or even a straight lines that has several points along them.

An ideal solution:
Ideally for each polyline I have coordinates for (upto 200 commands), I would like to put into the buffer (if this is the correct technique to dampen/eliminate/minimise the delay/stop/start), it would be great if the firmware can "plan" this route as to only truly accelerate and decelerate fully at the end of each route (polyline).

Any thought or advice would be greatly appreciated.

Thank you

Re: DC42 buffering gcode Host controller development
March 16, 2016 05:04PM
There is no need to wait for OK when sending gcodes to a Duet. The native USB port provides flow control at the driver level.

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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