This is a demonstration to give an example on how to use Linux with the current support for Time Sensitive Networking (TSN) as an industrial endpoint. For this purpose the components of this demonstration form a converged network use case in an industrial setting.
The Use Case Demonstration is aimed at the AccessTSN Endpoint Image and is tested with but should also work independently from the image.
This work is a result of the AccessTSN-Project. More information on the project as well as contact information are on the project's webpage: https://accesstsn.com
The AccessTSN Industrial Use Case Demo consists of multiple Git-projects, each holding the code to one component of the demonstration. This is the repository for the CNC control. It includes a module for Machinekit which writes control values from the Machinekit-HAL to a shared memory and the other way around. It also includes a setup for a 3-Axis mill as a demo machine. This setup is based on an example mill offered my LinuxCNC.
The main repository for AccessTSN Industrial Use Case Demo can be found on Github: https://github.com/iswunistuttgart/AccessTSN_Industrial_Use_Case_Demo
Currently only Debian or a debian derived Linux distribution is supported to run Machinekit and LinuxCNC. For correct execution and performance a real-time extension is also necessary. This project was tested with rt-preempt. It is recommended to use the AccessTSN Endpoint Image as a base.
The supplied configuration for LinuxCNC, called "AccessTSN 3axis Demo machine" uses a graphical user interface. The AccessTSN Endpoint Image does not include support for GUIs or a window manager. This needs to be installed as prerequisite. To keep the setup lightweight the XFCE4 desktop environment is recommended. It can be installed using apt:
sudo apt install xfce4
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Clone or download this project and its submodule to the destination folder on your hard drive.
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Install Machinekit-HAL for rt-preempt (and it's dependencies) either using the build package at https://cloudsmith.io/~machinekit/repos/machinekit-hal/packages/ or compile from source (https://github.com/machinekit/machinekit-hal)
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Install the LinuxCNC-EMC from the Machinekit Repository (and it's dependencies) either using the build package at https://cloudsmith.io/~machinekit/repos/emcapplication/packages/ or compile from source (https://github.com/machinekit/EMCApplication). Make sure to use compatible versions of Machinekit-HAL and EMCApplication. Tests were conducted with Machinekit-HAL version 0.4.20868-1 and EMCApplication version pre0.23585 installed from packages (https://dl.cloudsmith.io/public/machinekit/machinekit-hal/deb/debian/pool/buster/main/m/ma/machinekit-hal-rt-preempt_0.4.20868-1.gitca75c54aa~buster_amd64.deb and https://dl.cloudsmith.io/public/machinekit/emcapplication/deb/debian/pool/buster/main/e/em/emcapplication_2.9.0~pre0.23585.git42bf973af~buster_amd64.deb).
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Copy the accesstsn.3axis subdirectory to the linuxcnc/configs/ subdirectory in your home directory
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Compile and install the Machinekit-Component accesstsnshm.comp
Change to this projects folder
Compile and install the AccessTSN-Machinekit-Component (this needs root privileges):sudo comp --install accesstsnshm.comp
For easier setup the steps 2 through 5 of the manual installation above have been automated in the included install.sh script. This simplifies the installation to the following two steps/commands:
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Clone or download this project and its submodule to the destination folder on your hard drive.
git clone --recursive https://github.com/iswunistuttgart/AccessTSN_Industrial_Use_Case_Demo_CNC.git -
Execute install.sh from the AccessTSN Industrial Use Case Demo CNC directory. The script uses the sudo command so you will be asked for your password.
./install.shIf you want to run the script form a different place you can specify the path to the AccessTSN Industrial Use Case Demo CNC directory on the command line:
./install.sh <path-to-AccessTSN-CNC-project-directory>
The CNC Application can be started using the commandline. Either directly specify the AccessTSN 3Axis Demo Machine
linuxcnc ~/linuxcnc/accesstsn.3axis/accesstsn_3axis.ini
or start the CNC Application without arguments
linuxcnc
and use the LinuxCNC Configuration Selector (GUI) to chose the AccessTSN 3Axis machine.
Note: It is not possible to run the CNC Application with root privileges.
The AccessTSN Machinekit Component is a Machinekit HAL Component which supplies the interface between the shared memory used in the AccessTSN Industrial Use Case Demo and die Machinekit HAL. For the development of the AccessTSN Machinekit Component the HAL Component generator is used. For information on the Machinekit HAL please see the Machinekit documentation (for writing HAl Components: http://www.machinekit.io/docs/hal/comp/). The functions readin and writeout of the HAL component are periodically executed and with each execution data from the shared memory is copied to the Machinekit HAL and vice versa. The component makes the Shared Memory Data available to the Machinekit HAL through its "pins".
With this project a demo configuration for LinuxCNC is provided which represents a basic 3-axis milling machine. This AccessTSN 3Axis Demo Machine is aimed to be used together with the other projects of the AccessTSN Industrial Use Case. Therefore the values of the configuration match those of the axis simulation in the DriveControl project. The AccessTSN 3Axis Demo Machine can be found in the accesstsn.3axis subdirectory. This demo configuration is based on the 3 Axis example included in the LinuxCNC project. The (simulated) hardware setup is specified in the accesstsn_3axs.hal file. There the AccessTSN Machinekit Component is used to interface with multiple Shared Memories which are used for data exchange between the different applications of the AccessTSN Industrial Use Case Demo. The HAL-file also specifies the other connections between the various HAL components. The AccessTSN 3Axis Demo machine uses simulated limit and home switches. The behavior and position of those switches is specified in hallib/simulated_limits.hal. The parameters of the machine are specified in the accesstsn_3axs.ini file. The basic parameters of the Demo Machine are listed in table 1:
| Parameter | Value |
|---|---|
| Unit | mm |
| Cycle Time (task controller) | 0.001 s |
| Cycle Time (servo task) | 1 ms |
| Number of Axis | 3 (all identical) |
| Axis Setup | XYZ |
| Min position | -300 mm |
| Max position | 300 mm |
| Home position | 0 mm |
| Max velocity | 1 mm/s |
| Max acceleration | 508 mm/s² |
| Tool change position | (0,0,300) |
Table 1: Basic parameters of AccessTSN 3 Axis Demo Machine
The available milling tools are specified in the accesstsn_sim.tbl file. This can be extended if necessary. The chosen milling tool only has influence on the generated tool path and therefore on the set-point values, so no other parts of the AccessTSN Industrial Use Case Demo are affected by changes to this file. Table 2 lists the by default available milling tools.
| Toolnumber | Magazin position | Length in Z direction (mm) | Diameter (mm) | Description |
|---|---|---|---|---|
| T1 | P1 | 0.511 | 3 | 3mm end mill |
| T2 | P4 | 0.1 | 1.5 | 1.5mm end mill |
| T3 | P3 | 1.273 | 5 | 5mm tap mill |
| T4 | P2 | 10 | 16 | 16mm mill |
| T5 | P5 | 25 | 25 | 25mm mill |
| T6 | P6 | 6 | 6 | Tool6 |
Table 2: Default milling tools
Further information can be found in the Machinekit and LinuxCNC documentations.