The Gcode Sender widget will send a command to the serial port by default. You can optionally have it send the command to the 3D Viewer to have it move the toolhead in a simulation run. If you are going to run a real CNC job make sure to send the commands to the serial port.

When Playing or Stepping Send Gcode Commands To

When Clicking A Gcode Row Send Gcode Commands To

Pre-Upload Gcode to SPJS (Version 1.4 or higher of Serial Port JSON Server required)

Pre-Uploading gives the buffer a bunch of lines to work from to make sure you never starve your buffer. 100 lines is reasonable, but if you have a lot of small Gcode moves like in 3D printing a higher number may work. Up to 25,000 lines can be pre-loaded.

Multi-Line Upload Mode

How many lines to upload for each send to the Serial Port JSON Server. Since we're running in a browser and the user could be on a remote connection, sending 1 line at a time to the SPJS could be too slow based on your type of Gcode and the speed of your network connection. 3D prints for example are 100's of 1,000's of lines of gcode with tiny movements. Since each send to the SPJS requires a receipt to ensure ordering, this roundtrip latency can slow things down. One way to tackle this is to send multiple lines at a time. A good value is 50, but you can go up 20,000 if you'd like.

Delay Per Gcode Upload Event (i.e. per line)

The default is now 1000 ms delay, i.e. 1 second and to use Multi-Line upload with roughly 50 lines. 100 lines is also fairly normal now. The reason this new default is recommended is that it seems to put the least load on the browser so there are less round-trips to the Serial Port JSON Server. This setting also seems to stay ahead of the CNC controller nicely with most Gcode, so there's a constant set of available lines for the CNC controller to process.

If you are running version 1.4 or higher of the Serial Port JSON Server and you connected to your CNC controller with a buffer flow algorithm other than default (i.e. you chose the "tinyg" buffer algorithm when you connected to your TinyG), you can set this value as low as 5ms. In practice, a setting such as 20ms seems to do the trick. The reason is, the SPJS can now queue up to 25,000 lines of Gcode (which can be higher if for some reason you want 1,000,000 lines to queue. Just download the Github project and compile.).

In version 1.4 and up, the server will directly manage the planner buffer rather than the browser. You may notice that significantly more lines of Gcode are sent in to the server than where your CNC controller is actually at. You don't necessarily want too many lines sent in, but you want to make sure there's a really good buffer of lines as well. A good rule of thumb is to have the Serial Port JSON Server have 500 lines of Gcode in its buffer, i.e. this Gcode widget is 500 lines ahead of where the CNC controller is actually at.

For controlling a serial port device without a buffer flow algorithm, you should use a setting like a 200ms delay between the sending of each Gcode line. However, if you are seeing that the CNC controller is being starved of commands, and thus you are getting slow/choppy machining (especially on very small moves), you can lower this value by modifying this value here or forking this widget. The minimum value is 0. Be warned though, that by setting this value too low you can overflow the buffer and lose lines of Gcode which of course will destroy your milling job.

You can also raise this value if you are finding your computer is too slow to process everything and you are seeing that commands are being sent too quickly and overflowing the planner buffer. The main method of flow control is to get back a /plannerpause from the CNC controller widget. That makes the Gcode widget stop sending until it sees a /plannerresume. If there is contention in processing this command, increasing the delay per line gives time for your CPU to process the command. Values like 200ms have been seen to work quite well for ensuring there is ample time on slower processors. However, a delay like 500ms can also result in very slow commands to your CNC controller during small moves.

One final note, is that if you are running ChilPeppr on the same machine as your Serial Port JSON Server, you could find that you can run your job faster with less of a ms delay per line. Connecting over localhost is very fast and no packet loss will occur.

Play/Pause/Stop Feedhold/Resume/Flush

Tool Change (M6)

To send Gcode after pausing, add it here. This can be for moving to a tool change position.

To send Gcode before unpausing, add it here. This can be for moving back to the original position.

Definition of G-code to send as probe command in tool change dialog:

Pre-Process Gcode