By Tom Benedict
Photos by Author
Most CNC control software uses step & direction signals to control the axis motors on the machine. The controller that came with my Taig CNC mill does not use step & direction signals so this has limited what software I can use. And because the Taig CNC controller requires two parallel ports to control all four axes on my mill, this has limited what computer hardware I can use as well.
But no more! A fellow by the name of Peter Homann sells an add-on board called the TurboTaig that fixes both of these problems by converting the Taig controller to step & direction. This allows the Taig-owner to use a wider variety of software and will drive all four axes from a single parallel port.
This was enough to sell me on the idea, but the TurboTaig adds several other features as well. It has inputs for limit switches, relay outputs for spindle and coolant, and it can be configured to use other accessories like a digitizing touch probe and a spindle indexer for CNC threading.
Peter sells the TurboTaig from his web site. He is located in Australia, but he also distributes to the US and deals in US currency as well. I contacted Peter, bought the board, and waited anxiously for it to come.
A few days later a small box arrived, postmarked from Australia. Inside was the board, a manual, eight LEDs, and connectors for all the jumpers on the board. The manual is written clearly and covers the entire installation process. It is available as a PDF on Peter's web site, so you can read it before tackling this project.
The TurboTaig board fits inside the Taig controller. Installing the board requires you to drill and tap four holes inside the enclosure. Since metal chips and electronics don't mix well this involved partially disassembling the guts of the controller. None of the work required is outside the skill set of the typical home shop machinist, but it does take a little time and care. The picture shows the board mounted in my controller box.
My first impressions were very good. As advertised, I was able to drive all four axes out of a single parallel port. I was concerned that I wouldn't be able to drive the axes as fast as with my old setup, but this fear was completely unfounded. The motor characteristics did not change at all and I was able to keep the motor parameters I already had set up in my software.
Initially I didn't have anything wired up to take advantage of the added functionality of the board, but I remedied that as soon as I could. In addition to letting the computer know if an axis has over-run a limit, the board includes LEDs to indicate the status of the limit switches as well. It also has LEDs to indicate the status of each of the relay outputs. It only made sense that my first project should be a new faceplate for my controller. This would allow me to install the LEDs and add additional jacks for limit switches, relays, and everything else the board offered. The picture shows the new faceplate on my controller.
I have been using the TurboTaig board on my mill for several months now and still have only good things to say about it. If you've got a Taig mill and would like to use step & direction software with it, you might give the TurboTaig a look.