Remote control interface protocol for low level control

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1. Overview
2. Configuring low level control
3. Protocol commands

99% of all customers don't use this, but use Protocol v2 instead! This is a special mode where you send directional force and receive current position. You loose all other functionality.

To understand the protocol and be able to avoid pitfalls, please read "General information" before attempting to build packets.

Overview

The CLS system consisting of yokes / cyclics and pedals is intended to be used over CLS2Sim with supported flight simulation software.
If unsupported software is used, CLS2Sim has no way of communicating the steering values to the simulation.
Remote Control allows a 3rd-party application to define directional force on all axes of the CLS hardware, while receiving position information for said axes.
Using this, unsupported software can communicate with CLS2Sim and its hardware over a 3rd-party application.

Configuration

To use this feature. "Low level Control" in the connection settings window must be checked.
All other commands as well as all other CLS2Sim functionality will be deactivated!




If low level control is active, the main window will look like the image below.

Active/Passive mode

Active axes will use received forces to actively move into a direction defined by using positive or negative values for force.

Passive axes will want to remain at their position and use received forces to set their friction. (example: Collective)

Protocol

Packet format

CLS low level control for single seat

CLS low level control for dual seat

Example python script for using dual seat low level control

"""
Copyright 2021 Brunner Elektronik AG

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

----------------------------------------

CLS2Sim 3.20 or newer required.
Python 3.X required.

Example script to demonstrate low level control mode in a dual seat setup.

For packet information see:
https://cls2sim.brunner-innovation.swiss/RCInterface.htm
https://cls2sim.brunner-innovation.swiss/lowlevelcontrol.htm
"""

import socket
import struct
import time

timeout = 8

# Create a UDP socket
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)

# Set TTL to 5 to allow jumping over routers
sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, 5)

# Set socket timeout
sock.settimeout(timeout)

# IP address of machine running CLS2Sim
host = '127.0.0.1'
# Default UDP port configured in CLS2Sim
port = 15090

# Initialize variables
force = [0,0,0,0,0,0,0,0]
pos = [0,0,0,0,0,0,0,0]

# set maximum force
maxForce = 2000

# main loop
while True:
    # calculate new forces
    for i in range(0,8):
        force[i] = int((pos[i] - 0.5) * maxForce * 2)

    # Construct a packet consisting of one unsigned integer (command) and 8 signed integers (force data)
    request = struct.pack('<Iiiiiiiii', 0xAE, force[0], force[1], force[2], force[3], force[4], force[5], force[6], force[7]), (host, port)
    # Send packet
    sock.sendto(request)
    
    # Receive response
    response, address = sock.recvfrom(8192)
    # Read current positions from response, one unsigned integer(command) and 8 floats (position data)
    result, pos[0], pos[1], pos[2], pos[3], pos[4], pos[5], pos[6], pos[7] = struct.unpack('<Iffffffff', response)
    
    # Print force for aileron pilot and aileron copilot axes
    print(force[2], force[3])

    # wait at least 1 ms
    time.sleep(0.001)