HMI Errors and Communication Faults

Problem

The HMI shows an error or communication message, loses values or screens, or fails to start with the controller. Machine behavior may continue or stop depending on where the fault sits.

Possible Causes

1. Communication cable or connector fault between HMI and controller.
2. Controller or HMI stuck in an abnormal state after a power event.
3. Electrical noise or grounding conditions affecting communication.
4. Power interruption during operation.
5. Parameter or project mismatch after a component replacement.

What to Check

• STEP 1Record the exact error text.Photograph the screen including any code — never clear it before recording.
• STEP 2Check cables and connectors.Verify the communication cable is seated at both ends and undamaged, including its route away from power cables.
• STEP 3Restart per the machine manual.Follow the documented restart sequence for the HMI and controller — order matters.
• STEP 4Review recent electrical work.Check whether nearby electrical changes coincide with the fault's first appearance.
• STEP 5Check for a replacement event.If the HMI or controller was replaced, verify parameter and project sets were transferred completely.

Corrective Actions

• Reseat and secure communication cabling; keep it routed per the original layout.
• Bring the documented restart procedure to the panel so it is followed exactly.
• Never load or edit controller projects without authorization from Path Pack.
• Escalate with the photographed error text and the sequence that leads to it.