rtbessential2d

Radar Test Bench - Essential 2D Control Library

Preconditions

Please ensure that the following tools are installed and appropriately advertised via the PATH environment variable.

Linux

• gcc (apt install build-essential)
• CMake (apt install cmake)

Windows

• MSVC (Microsoft Visual C++ or Microsoft C++ Build Tools) compiler toolchain
• make (install choco and then install make with choco install make)
• CMake

Hardware

• Radar Test Bench - Essential 2D

Build

git clone --recurse-submodules https://github.com/dspace-group/rtbessential2d.git

cd rtbessential2d/
mkdir build
cd build

cmake ..
cmake --build .

Example

>>> import pyrtb as Pyrtb
>>> pyrtb = Pyrtb.Pyrtb('build/librtbessential2dctl.so')
>>> pyrtb.Get_interfaces()
[{'name': 'enp0s31f6', 'desc': 'enp0s31f6'}, {'name': 'enx00116b683f83', 'desc': 'enx00116b683f83'}]

>>> pyrtb.Start("enx00116b683f83")
Nanotec Electronic GmbH - N5 EtherCAT Drive, slave 2 set, retval = 39
Nanotec Electronic GmbH - N5 EtherCAT Drive, slave 3 set, retval = 39
Slaves in SAFE_OP
Start working loop...done
Slaves in OP
0

>>> ms = pyrtb.Get_motor_status()
>>> print(ms[0]) # motor 1
Motor control:
- Control word: 31
   Switch on: On
   Enable voltage: On
   Quick stop: On
   Enable operation: On
   Fault reset: Off
   Halt: Off
   Begin on time: Off
- Target position: 0
- Motor drive submode select: 65
   CL/OL: On
   VoS: Off
   Brake: Off
   Current Reduction: Off
   AutoAl: Off
   Torque: Off
   BLDC: On
   Slow : Off
- Modes of operation: 6, 'homing mode'
Motor status:
- Status word: 5687
   Ready to switch on: On
   Switched on: On
   Operation enabled: On
   Fault: Off
   Voltage enabled: On
   Quick stop: On
   Switch on disabled: Off
   Warning: Off
   Remote: On
   Target reached: On
   Internal limit active: Off
- Modes of operation display: 6, 'homing mode'
- Position: 0
- Velocity: 0

>>> pyrtb.Enable_enpo()
0

Python wrapper functions

• pyrtb = Pyrtb.Pyrtb(path) Initialize Python pyrtb wrapper with the path to the shared library (.so or .dll)
• pyrtb.Get_state() Returns the current state of the library (0: Initialized, 1: Starting, 2: Started)
• pyrtb.Get_interfaces() Returns a list of interfaces (names and descriptions)
• pyrtb.Start(interface_name) Start EtherCAT Master on the given interface
• pyrtb.Stop() Stops EtherCAT Master
• pyrtb.Get_detected_slaves() Returns a list with the detected EtherCAT Slaves
• pyrtb.Set_correction_factor(cf_m1, cf_m2, offset_m1, offset_m2) Set correction factors and offsets for motor1 and motor2
• pyrtb.Set_angles(az, el) Set azimuth and elevation (in deg)
• pyrtb.Get_angles() Returns a (azimuth, elevation) tuple
• pyrtb.Enable_enpo() Enable (or disable with False as argument) motor controller enpo. Motors won't move if enpo isn't enabled. After initialization enpo is disabled.
• pyrtb.Set_operation_mode(om) Switch operation mode to homing (6) or to positioning (1)
• pyrtb.Ack_error() Reset motor errors
• pyrtb.Enable_homing() Enable homing
• pyrtb.Get_motor_status() Return list with status objects for for motor1 and motor2. (print(pyrtb.Get_motor_status()[0]))
• pyrtb.Get_simulation_time() Return list with the current simulation time and the current simulation step. The values are updated only when the EtherCAT network is in operation.

Cooking recipe

1. Build library as documented above
2. Start a Python interpreter and load the wrapper with import pyrtb as Pyrtb. If your user doesn't have the rights to control the Ethernet interface of your computer, then start the Python interpreter with elevated user rights (Windows: Run as Administrator, Linux: sudo python)
3. Create a wrapper object and load the shared library with >>> pyrtb = Pyrtb.Pyrtb('../build/librtbessential2dctl.so')
4. List the available interfaces with >>> pyrtb.Get_interfaces()
5. Start EtherCAT Master. E.g. with >>> pyrtb.Start('eth0')
6. Check whether RTB EtherCAT Slaves were found with >>> pyrtb.Get_detected_slaves()
7. Use pyrtb.Enable_enpo(), pyrtb.Set_correction_factor(), pyrtb.Set_angles(az, el), pyrtb.Enable_homing() to write your application.
8. Use pyrtb.Ack_error(), pyrtb.Get_motor_status(), pyrtb.Get_simulation_time() for debugging purposes.

NOTE: To set the angles, first disable enpo (pyrtb.Enable_enpo(False)), set the operation mode to positioning (pyrtb.Set_operation_mode(1)), enable enpo (pyrtb.Enable_enpo(True)) and pyrtb.Set_angles(az, el).

Dependencies

This work depends on SOEM(License), a simple open EtherCAT Master Library. SOEM on Windows depends on WinPCap or Npcap. Note that neither WinPCap nor Npcap are open source software.

Windows

• WinPCap or Npcap

Acknowledgement

Powered by dSPACE TargetLink and SOEM.