Home

March 2011, the rt-stepper software is now based on the EMC2 project at www.linuxcnc.org. This means the rt-stepper software now supports 4-axis, complete gcode interpreter, trajectory planner, GUI front-end, Backploting and more. The best part is since the rt-stepper dongle provides the real time step pulses, you can now run EMC2 on Linux, Mac and Windows.

Eckler Software offers a unique USB solution for CNC controllers with the rt-stepper USB-to-Parallel dongle. Users can use the rt-stepper dongle to convert a parallel port CNC controller into a USB CNC controller. Designers can integrate the rt-stepper dongle hardware into there own CNC controller.

Most CNC controllers are designed to be driven with a PC parallel port. Unfortunately parallel ports are thing of the past and many new PCs have no parallel port. Commercial USB-to-Parallel dongles do exist, but these dongles are designed for printers not CNC controllers. CNC controllers require XYZ step/direction signals. With the rt-stepper dongle you can now drive XYZ step/direction signals over the USB bus.

Driving a CNC controller with a PC parallel port requires a real time OS otherwise the stepper motors can loose synchronization. With the rt-stepper dongle this restriction is removed. The rt-stepper dongle provides the real time stepper motor control which means you can now use your favorite OS such as Linux, Mac or Windows. Each dongle provides a step resolution of 46,875 Hz.

Most commercial gcode interpreters do NOT support laptops with parallel port chipsets. This is not a problem with the rt-stepper dongle. You can use any Linux, Mac or Windows laptop or netbook with USB support. Laptops can provide dedicated CNC setups with minimal investment and work space.

The rt-stepper software (rtstepper_emc) is open source. Starting with version 1.7 the software is based on the EMC2 open source project at www.linuxcnc.org. There are two processes that run on the PC - TkMini and milltask. TkMini is a GUI front-end program that communicates through the milltask to the dongle. The milltask process performs the gcode translation, trajectory planning and rt-stepper IO. Together they act as a real time stepper motor gcode virtual machine. Both manual and auto CNC operations are supported.

TkMini main screen is showed below, for more screen shots see the rt-stepper External Reference Specification (ERS).

The rt-stepper software supports the same gcode interpreter as EMC2. See the "Gcode Overview" section at www.linuxcnc.org for program syntax, parameters, expressions, binary operators, functions and looping constructs. See the ERS for rt-stepper specific features and instructions.

I started using EMC back in 2002. I developed this product after using EMC for several years with my Sherline CNC mills. EMC worked great, but requires a PC with a real-time kernel and a parallel port to control the mill. Now I have the best of both worlds EMC2 based software with no real-time kernel requirements.

I have two mills and two CNC controllers - Camtronics and Xylotex. I now use the rt-stepper software exclusively. I can use the latest notebooks, which have no parallel port, with my old CNC controllers.

I first introduced the rt-stepper dongle back in 2009 with my own small terminal program that ran a small subset of CNC gcodes. I have no plans for new development on the rt-stepper classic software, but rt-stepper classic software is still available on the download page.

Currently I'm eating my own "dog food" with this product. This means I actually use rt-stepper to build the USB-to-parallel dongle. Both the dongle PCB and case are milled with rt-stepper. You don't get a feel for a product unless you use it.

I used Eagle CAD to develop and build the PCB. The engraving software I used for the case is called engrave-11-inline. Engrave-11-inline is a good example of using a real programming language, in this case python, to develop gcode output.

The rt-stepper dongle hardware is based on the Microchip PIC182455 processor. If you are board designer and would like to integrate the dongle hardware into your own application. I am willing to sell you preprogrammed pic chips for your application. Based on my sublicense agreement with Microchip this arrangement works best because each pic chip must be programmed with unique USB descriptors (ie: pid/vid, serial number, product ID).

Be sure to use the rt-stepper dongle as your reference design with your application. Because any hardware or software support would be based on the dongle only. Please email me for more information.