Sender Software#
There are 3 main options for interfacing with your CNC machine. A dedicated sender software, a design package, or an offline controller.
Dedicated sender software#
A dedicated sender software has only one purpose - to operate the CNC machine. It will provide the best experience if you only need to execute your existing G-code files.
Such software will show the current machine state, tool position, and other information.
It will have UI for moving the machine in space (jogging) and perform actions like loading and running a G-code file, Z probing, adjusting the machine configuration. You will get a text console where you can type direct commands for the machine and view the results.
Often you will see a 3D view that displays the toolpaths from the loaded file as well as the current progress during jobs.
Popular programs are Candle, OpenBuilds CONTROL, UGS, gSender.
Design packages#
A design package lets you design your models and toolpaths and then send them to the machine.
The sender functionality of the package can be limited. That’s because it is not the main focus of the software, and also needs to support multiple firmware platforms besides Grbl.
The main benefit here is the tight integration of the end-to-end workflow. You can do all of your work without leaving the software.
Popular such packages are VCarve, Carbide Create, Easel, Lightburn.
Offline controller#
An offline controller is a piece of hardware that connects directly to the control box. You load the G-code on it using a memory card.
Sometimes a controller can be built into the control box itself
A major limitation of most controllers that are included with hobby machines is that they have a small screen and limited functionality.
Of course there are more expensive devices that have larger screens, physical buttons, and more features like Wi-Fi connectivity.
An offline controller has two main benefits. First, you don’t need a PC to be close by, like in a garage or a workshop setting. And second, it reduces the errors from electromagnetic interference because of the close proximity to the machine.
On the other hand, having to save the G-code to a memory card could be a major issue when iterating on a project. This is less of a problem if you have a file that is production-ready and you want to run it multiple times.
Which one is best?#
My recommendation is to always start with a dedicated sender software when you first assemble and configure the machine. Such program is specifically designed for Grbl and offers superior troubleshooting capabilities. You get direct access to every setting and you will see meaningful error messages when things go wrong.
Once you get everything working, you can switch to something else that fits your workflow best.
My personal workflow is to create models and toolpaths in Fusion 360, export the G-code file, and use OpenBuilds CONTROL as a sender.
PC sender and offline controller together#
As a general rule, do not, ever, run a sender software and an offline controller at the same time. They share the same serial channel to the motion controller. As they both can send commands at the same time, the commands will get corrupted.
However, just like you can cross the streams in extreme situations, there are cases where this can be beneficial.
Imagine that you are having a problem that only happens with the offline controller. Maybe the Z probe doesn’t work. Or jogging a certain axis is misbehaving. The offline controller has limited ability to respond to errors.
If you have a PC sender connected at the same time, it will receive the same error information and could display it in a more meaningful way. Do not execute any operations from the PC. Only use it for display. Keep a close eye on the machine in case it starts acting erratically so you can stop it immediately.