Hi, when using the `RobotiqGripper` interface from **ur_rtde**, the gripper reports a native device range of **0–255**, but the actual reachable position appears to be lower (around **230** in my case). When commanding `move(255)`, the gripper stops around **230** and never reaches the expected maximum value. This creates inconsistencies when working with: * `UNIT_DEVICE` * `UNIT_NORMALIZED` * `UNIT_MM` because the library assumes a full **0–255** device range. --- # Environment ``` OS: Ubuntu 24.04.3 LTS ROS: ROS2 Jazzy ur_rtde: 1.6.0 Robot: Universal Robots UR10e Gripper: Robotiq 2F-140 Connection: Robotiq URCap socket interface ``` --- # Minimal Reproducible Example ```cpp #include <ur_rtde/robotiq_gripper.h> #include <iostream> #include <thread> #include <chrono> using namespace ur_rtde; int main() { std::cout << "Robotiq range test" << std::endl; RobotiqGripper gripper("123.45.67.89", 63352, true); gripper.connect(); std::cout << "Activating gripper..." << std::endl; gripper.activate(); // Use raw device units gripper.setUnit(RobotiqGripper::POSITION, RobotiqGripper::UNIT_DEVICE); // Print configured range int min_native, max_native; gripper.getNativePositionRange(min_native, max_native); std::cout << "Configured native range: " << min_native << " - " << max_native << std::endl; std::cout << std::endl; // Try to close completely std::cout << "Commanding position 255..." << std::endl; gripper.move(255, 50, 50, RobotiqGripper::WAIT_FINISHED); std::this_thread::sleep_for(std::chrono::milliseconds(200)); // Read raw device position int pos = gripper.getVar("POS"); std::cout << "Requested position: 255" << std::endl; std::cout << "Reported position: " << pos << std::endl; if (pos != 255) { std::cout << "WARNING: position never reaches 255" << std::endl; } std::cout << std::endl; gripper.open(); std::cout << "Disconnecting..." << std::endl; gripper.disconnect(); return 0; } ``` --- # Observed Output ``` Configured native range: 0 - 255 Commanding position 255... RobotiqGripper::move: 255 Requested position: 255 Reported position: 230 WARNING: position never reaches 255 ``` --- # Expected Behaviour If the reported native range is **0–255**, commanding `move(255)` should result in a final reported position of **255**. --- # Actual Behaviour The gripper stops around **230**, even though the reported range is **0–255**. --- # Additional Notes This behaviour suggests that the actual physical range of the gripper may be smaller than the nominal device range. However, since the library reports a full **0–255** range through `getNativePositionRange()`, it can lead to incorrect scaling when using the higher-level unit conversions (`UNIT_NORMALIZED` or `UNIT_MM`). # Question Is this behaviour expected for the Robotiq gripper when using the URCap socket interface? In other words, is it normal that the gripper never reaches the full device value `255` even though `getNativePositionRange()` reports a range of `0–255`? If this is the intended behaviour, should users assume that the effective maximum position is lower than 255 and handle the scaling manually when using `UNIT_DEVICE`, `UNIT_NORMALIZED`, or `UNIT_MM`? Alternatively, could this indicate that I am misusing the interface or missing some configuration or calibration step? Any clarification on the correct interpretation of the device position range would be greatly appreciated.