I determined that a Mach 3 CNC pendant wasn’t going to work in LinuxCNC with merely configuration file changes, so I started looking at other pendant options. I found this bare-bones option(*) that had only a few controls and no display screen, and almost every single function is broken out into its own physical wire. This fits very well with the LinuxCNC model built on the idea every I/O is a pin. Even when it’s not literally a pin on a parallel port, there’s a logical pin underneath for LinuxCNC configuration.
And while looking at these pendants designed for hard wiring, I found a controller that bundles such a pendant with a complete self-contained CNC controller unit. It is more capable than Grbl on an Arduino, but less than full LinuxCNC on a PC. It calls itself an offline motion controller system(*), running software from Digital Dream Automation. At a quoted maximum pulse rate of 500 kHz, it significantly outperforms Arduino Grbl which is reported to top out at around 30 kHz. This unit can also read G-Code from a USB flash drive, eliminating the need to have a separate computer running some sort of G-Code sender program to Grbl. A nice self-contained (I guess that’s what they meant by “offline”?) system.
Minor problem: G-code visualization options on such a little screen seems to be limited to 2D plots, giving up one of three axes. I’ve seen old CNC with the same limitation so it’s not a huge deal, but it is less than what we can do with modern PC-based systems.
Moderate problem: How would I generate G-code for these units? This particular unit’s owner’s manual explains firmware updates would be downloaded from ddcnc.com, and that’s how I found Digital Dream and presumably they are the author of software running on these units. Unfortunately, a quick search for Digital Dream on Fusion 360 post processor library came up empty. I don’t know how owners of DDCNC-based controllers like this one generates their G-code programs. The user manual has a list of supported commands, but I’m not familiar enough with the various styles to recognize if DDCNC uses the same set of code as something else.
Major problem: Buying such a product instead of setting up LinuxCNC comes with a drawback: I can’t dig into the code and learn how CNC controllers work under the hood. And that is the primary point of my CNC controller explorations. If someone asks me for a ready-made upgrade over Grbl on Arduino or ESP32, I’m happy to let them know these controllers exist. But for myself, I’ll resume my LinuxCNC explorations.
(*) Disclosure: As an Amazon Associate I earn from qualifying purchases.