Custom Profile Demo

custom_profile_demo

Minimal example of a custom device profile. It binds a user-defined profile (demo::A6ExtendedProfile, a subclass of ecdev::CiA402DriveProfile) to a StepperOnline A6 servo, brings the bus up, prints the drive's current actual position once, and shuts down.

It demonstrates the whole custom-profile lifecycle without any motion:

• Extend, don't reimplement. A6ExtendedProfile subclasses the built-in CiA402DriveProfile (which is not final) and overrides only what it needs, chaining to the base. Because the subclass inherits asMotion(), the Axis facade keeps working unchanged. To expose an extra vendor PDO variable you override readInputs (and optionally resolveTopology) and snapshot your object into your own atomics -- see the commented template in main.cpp.
• Static factory. A6ExtendedProfile::make maps ProfileSelectionInput to a profile instance; main() passes it to makeIdentityProfileFactory (same role as ecdev::makeCiA402DriveProfile).
• Register for one run. main.cpp pushes a factory onto NetworkConfig::extra_profile_factories, which is considered ahead of the built-in device classes, so no static registration or whole-archive linking is needed.
• Reach it from the app. The application recovers the custom type from Axis::deviceProfile() without RTTI -- this is an RT system, so it guards on the unique profileName() and static_casts once at setup (no dynamic_cast), then uses its extra API.

Requirements

This demo uses CiA402DriveProfile subclassing and DeviceFacade::deviceProfile(), which are part of the LXMASTER profile-extension API. You need an installed LXMASTER package that includes those (rebuild + cmake --install from the LXMASTER source tree if your installed package predates them).

Build

cmake -B build
cmake --build build -j

If LXMASTER is installed to a non-default prefix, point CMake at it with -DCMAKE_PREFIX_PATH=/your/prefix.

Run

1. Generate an ENI for your bus (lxmaster eni gen -h) and set the path in kEniPath in main.cpp (or edit it to read from argv).
2. Ensure LXMASTER_RT_IFACE is set (via lxmaster host setup).
3. Run on the RT host (e.g. lxmaster run custom_profile_demo, or the binary directly with the appropriate privileges).

Expected output is one line reporting the bound custom profile and one line with the axis actual position, then Done.

Source: main.cpp

#include <chrono>
#include <cstdint>
#include <cstring>
#include <iostream>
#include <memory>
#include <thread>
#include <vector>

#include <lxmaster/lxmaster.hpp>

// Direct device-layer headers (installed with the package) for binding a custom profile.
#include "devices/cia402_drive_profile.hpp"
#include "devices/identity_profile.hpp"
#include "devices/profile_registry.hpp"

/**
 * Minimal custom device profile for the StepperOnline A6 servo.
 *
 * It extends the built-in `ecdev::CiA402DriveProfile` (which is not `final`) instead of
 * reimplementing the motion contract. Because the subclass inherits `asMotion()`, the `Axis`
 * facade keeps working unchanged -- the application still commands/reads motion through `Axis`.
 *
 * As shipped this subclass only renames the profile (to prove a custom class is in use). To expose
 * an EXTRA vendor PDO variable -- some object the ENI maps beyond the standard CiA402 set -- override
 * the lifecycle methods below and CHAIN to the base, e.g.:
 *
 *   void readInputs(const ecdev::ProcessImage& image, bool wkc, bool op) override {
 *     CiA402DriveProfile::readInputs(image, wkc, op);  // base motion snapshot first
 *     std::int32_t v = 0;
 *     if (wkc && image.readI32(extra_ref_, &v)) extra_.store(v, std::memory_order_release);
 *   }
 *
 * The application reaches this subclass through `axis->deviceProfile()` (see main() below).
 */
namespace demo {

class A6ExtendedProfile : public ecdev::CiA402DriveProfile {
public:
  using CiA402DriveProfile::CiA402DriveProfile;

  const char* profileName() const override { return "a6-custom"; }

  /** Build from registry selection input (mirrors `ecdev::makeCiA402DriveProfile`). */
  static std::unique_ptr<ecdev::IDeviceProfile> make(const ecdev::ProfileSelectionInput& in) {
    ecdev::CiA402DriveProfile::Config cfg;
    cfg.op_mode = in.op_mode;
    cfg.auto_fault_reset_and_recover = in.auto_fault_reset_and_recover;
    cfg.startup_fault_autoreset = in.startup_fault_autoreset;
    return std::make_unique<A6ExtendedProfile>(cfg);
  }

  // Extra vendor PDO state would live here (resolved ref + lock-free snapshot):
  // private:
  //   ecdev::PdoEntryRef extra_ref_{};
  //   std::atomic<std::int32_t> extra_{0};
};

}  // namespace demo

/**
 * Minimal custom-profile demo.
 *
 * Binds `demo::A6ExtendedProfile` to the StepperOnline A6 servo, brings the bus up, prints the
 * drive's current actual position once, and shuts down. Registration is via
 * `NetworkConfig::extra_profile_factories`; the bound profile is reached through
 * `Axis::deviceProfile()`.
 *
 * Edit kEniPath to point at an ENI generated for your bus (`lxmaster eni gen -h`).
 */
namespace {

constexpr std::uint32_t kA6VendorId = 0x00400000;
constexpr std::uint32_t kA6ProductCode = 0x00000715;
constexpr const char* kEniPath = "/home/user/myenifolder/myenifile.xml";

}  // namespace

int main() {
  lxmaster::NetworkConfig cfg = lxmaster::NetworkConfig::defaults();

  if (cfg.bus.ifname.empty()) {
    std::cerr << "No EtherCAT interface: set LXMASTER_RT_IFACE in /etc/profile.d/lxmaster-config.sh "
                 "(run lxmaster host setup first).\n";
    return 1;
  }

  cfg.eni.eni_path = kEniPath;

  cfg.extra_profile_factories.push_back(ecdev::makeIdentityProfileFactory(
      ecdev::DeviceIdentityMatch{kA6VendorId, kA6ProductCode}, demo::A6ExtendedProfile::make,
      "cia402:a6-custom"));

  lxmaster::EcNetwork net(cfg);

  if (!net.prepare()) {
    std::cerr << "EcNetwork::prepare() failed: " << net.lastError() << "\n";
    return 1;
  }

  std::vector<lxmaster::Axis*> axes = net.axes();
  if (axes.empty()) {
    std::cerr << "ENI produced no motion axes (is the A6 present and mapped in the ENI?).\n";
    return 1;
  }

  lxmaster::Axis* drive = axes.front();
  drive->setDriveMode(lxmaster::DriveOpMode::Csp);
  drive->configure();

  if (!net.start()) {
    std::cerr << "EcNetwork::start() failed: " << net.lastError() << "\n";
    return 1;
  }

  // RTTI-free downcast: this is an RT system, so guard on the unique profileName() and static_cast
  // (done once here at setup, not on any cyclic path).
  ecdev::IDeviceProfile* prof = drive->deviceProfile();
  if (prof != nullptr && std::strcmp(prof->profileName(), "a6-custom") == 0) {
    auto* mine = static_cast<demo::A6ExtendedProfile*>(prof);
    std::cout << "Custom profile in use: " << mine->profileName() << "\n";
  }

  std::this_thread::sleep_for(std::chrono::milliseconds(50));

  std::cout << "Axis '" << drive->name() << "' actual position = " << drive->actualPosition()
            << " counts\n";

  net.stop();
  std::cout << "Done.\n";
  return 0;
}