Hello there, I have a Robotiq 2F-85 attached to a UR3e robot, the robot is connected to my laptop via a wired ethernet network. I'm using python code very similar to a different post to control the gripper over a socket connection, link and minimal code example below. I can set target position, speed, force etc without issue, I can read back the actual position, gripper status etc, BUT: when I try to read the motor current, it always returns zero, regardless of whether or not the gripper is holding something. Any idea what might be the problem? Is there some action that must be taken for the motor current to be written to its respective register?

Code source:
https://dof.robotiq.com/discussion/2420/control-robotiq-gripper-mounted-on-ur-robot-via-socket-communication-python

Code:

robotiq2f_tcp.py

import socket
import time


class Robotiq2F85TCP:

    def __init__(self, host_ip: str, port: int = 63352) -> None:
        self.host_ip = host_ip
        self.port = port

    def _communicate(self, command: str) -> str:
        """Helper function to communicate with gripper over a tcp socket.
        Args:
            command (str): The GET/SET command string.
        """
        with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
            try:
                s.connect((self.host_ip, self.port))
                s.sendall(("" + str.strip(command) + "\n").encode())

                data = s.recv(2 ** 10)
                return data.decode()[:-1]
            except Exception as e:
                raise (e)

    def activate_gripper(self):
        """Activates the gripper, sets target position to "Open" and sets GTO flag."""
        self._communicate("SET ACT 1")
        while not self._communicate("GET STA") == "STA 3":
            time.sleep(0.01)

        # initialize gripper
        self._communicate("SET GTO 1")  # enable Gripper
        self.target_position = 0
        self.speed = 255
        self.force = 0

from robotiq2f_tcp import Robotiq2F85TCP

robotiq = Robotiq2F85TCP("10.42.0.162")

# activate and wait for 4sec for calibration procedure (gripper opens and closes)
robotiq.activate_gripper())
time.sleep(4)

print(robotiq._communicate("GET COU"))

The force parmeter will the define the current threshold which will stop the motor. The more force you have the more will be the threshold.
The gripper is looking for a pick of current. Once this pick is detected the current is set to 0 if the force is 0 or few mA if the force is more than 0.
After grip, the current is the same whatever the value of the force parameter.
With a force parameter at more than 1 the gripper always try to close to keep fingers as close as possible from each others. That is way the motor consum few mA.