Overview
This article addresses a specific system failure where the Web App reports "0 Slaves Connected" and the control box's green LED is flashing irregularly. This combination typically indicates that the controller's logic is active, but it cannot establish a handshake or provide power to the robot arm's communication chain.
System Symptoms
LED Feedback: The green LED on the control box is not stable (blinking or flickering instead of solid).
Arm Power: The end effector (flange) LED is completely inactive.
Control Box: Shows error with the amount of active slaves (all slaves are missing).
Diagnostic Steps
1. Emergency Stop (E-Stop) & Reset Verification
Before testing internal components, ensure the hardware safety circuit is physically closed. A pressed E-Stop will prevent the power-on handshake.
Check the Physical Button: Ensure the emergency push button (on the teach pendant or control box) is fully released. Rotate the button to ensure it "pops" out.
Toggle the State: Even if it appears released, press it down firmly and release it again to ensure the internal contacts are properly seated.
Emergency button released
Emergency button pressed
2. Cable & Connector Inspection
An unstable LED can be caused by a "high-resistance" connection or intermittent data flow.
Pin Integrity: Inspect the heavy-duty cable for pin corrosion, bent pins, or loose seating.
3. Voltage Isolation Test
Because the green LED is unstable, this might indicate a problem with the power supplied to the cobot.
Check Control Box Output: Use a multimeter to measure the voltage at the heavy-duty connector pins.
Target Voltage: You must confirm a stable 48V DC. If the voltage is fluctuating in sync with the green LED, the internal Power Supply Unit (PSU) or control board is faulty.
4. First Joint (Slave 1) Verification
If the controller is failing to see any slaves, the break is usually at the very beginning of the chain (the base of the robot).
Remove the cover of the first joint.
Measure the voltage difference between the red and black wires at the screw terminals.
Caution: Ensure you do not touch the robot chassis or the board directly during this measurement to prevent a potential short circuit.
